## v9.10

Version 9.10, released on June 24, 2023.
List of changes with respect to version 9.8.
<!-- Release notes updated on July 11, 2023. -->

Many thanks to the contributors to the ABINIT project between
September 2022 and April 2023 (with some late contributions until June 2023).
These release notes
are relative to modifications/improvements of ABINIT v9.10 with respect to v9.8.
<!-- Merge requests up to and including MR919. Also, MR923 to MR925 and MR928 are taken into account. -->

The list of contributors includes:
J. Abreu, F. Akhmetov (Radioteddy on github), J.-M. Beuken, A. Blanchet, F. Bruneval, M. Cote, M. Giantomassi, X. Gonze, B. Guster, P. Kesterner,
L. Mac Enulty, M. Mignolet, D.D. O'Regan, S. Rostami,
M. Royo, A. Sasani, M. Stengel, M. Torrent, M. Verstraete, A. Zabalo, J. Zwanziger.

It is worthwhile to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

### **A.** Important remarks and warnings. 

**A.1** The names of several tutorial files have been changed to make them easier to understand. "gspw" is now "paral_bandpw", "ucrpa" is now "ucalc_crpa",
"depes" is now "eph_tdep_legacy", "eph" is now "eph_legacy", "ffield" is now "polarization". The tutorial "udet" relying on an old utility
is now superceded by the tutorial "lruj", see section [B.3](#v9.10.B.3). The name of the topic CRPA has been changed to [[topic:CalcUJ]].

**A.2** The default value for [[dosdeltae@anaddb]] has been changed from 1 cm-1 to 0.2 cm-1, 
and the default value for [[dossmear@anaddb]] has been changed from 5 cm-1 to 1 cm-1.
Also, the default values for [[dosdeltae@atdep]] has been changed from 4.5d-6 to 0.2 cm-1.
This is to allow default calculations of thermal expansion using abipy to be more stable numerically.

By S. Rostami and X. Gonze (commit 8b7697502c)

* * *

### **B.** Most noticeable achievements

<!-- **B.1** Low-scaling GW and RPA implementations 

A cubic scaling real space imaginary time algorithm for GW and RPA has been implemented.
See the theory in [[cite:Liu2016]] and related references. It relies on the minimax time-frequency grids
available in the GreenX library (reference to be provided).
At present: only norm-conserving pseudopotentials can be used, restriction to non-magnetic materials,
and without spin-orbit coupling.
Still, different types of flows and algorithms (including self-consistency) are available, see [[gwr_task]].

Activate it using [[optdriver]]=6, and specify [[gwr_task]].

New input variables : [[gwr_task]], [[gwr_chi_algo]], [[gwr_sigma_algo]],
[[gwr_np_kgts]], [[gwr_ucsc_batch]], [[gwr_ntau]], 
[[gwr_boxcutmin]], [[gwr_max_hwtene]], [[gwr_rpa_ncut]], [[gwr_nstep]]. Also, [[gwr_tolqpe]] replaces the obsolete gw_toldfeig input variable.

Tests are provided in the newly created subdirectory tests/gwr, see tests 01 to 07 (not yet activated).
See also test:paral_78 and test:paral_79 (not yet activated).

By M. Giantomassi (MR875, MR907)
-->

**B.1** Orbital magnetization 

The computation of the orbital magnetization and chemical shielding
(in the converse method, that is, with a nuclear dipole moment added)
has been implemented, as described and tested in
[[cite:Zwanziger2023]].  This implementation works for insulators and
metals, with [[nspinor]]=1 and 2. However it works with PAW only, not
with NC pseudopotentials.  Lamb shielding is treated. The PAW atomic
dataset generator "Atompaw" has been updated accordingly to compute
and output the Lamb shielding in xml files.

See [[test:v9_44]], [[test:v9_140]], [[test:v9_141]], [[test:v9_142]], [[test:v9_143]], and [[test:nuc_4]],
with input variables [[orbmag]], [[nucdipmom]], [[lambsig]].

The [[tutorial:nuc| tutorial on properties at nuclei]] has been modified to present such computations.

By J. Zwanziger, M. Torrent and X. Gonze (MR895, 904, 917).


**B.2** Natural optical activity tensor, linear response to a vector potential (orbital magnetic field linear response) and other modifications of the longwave driver.

Computation of the natural optical activity tensor can be performed via the input variable [[lw_natopt]].
This is demonstrated with the test [[test:lw_8]]. 
The topic [[topic:longwave]] has been upgraded.

In addition, the computation of the linear response to a vector potential in the long-wavelength limit 
has been implemented via minimal modifications of the routines that calculate second derivatives 
of wavefunctions with respect to wavevector as explained in [[cite:Zabalo2022]].
See test [[test:v9_146]], and input variable [[rf2_dkdk]] with value 2.
Related test [[test:v9_147]].

These are by-products of large modifications of the longwave driver, mimicking the structure of the nonlinear one.
Other improvements related to the large modifications:
i) the number of source code lines has been reduced.
ii) the number of I/O operations has been reduced.
iii) symmetries are now used in order to calculate only linearly independent components of the tensors. This also reduces the number of linear-response functions to precalculate.
iv) the whole structure is now more general, thus facilitating the implementation of future spatial dispersion quantities.

Also, the new input variable [[ffnl_lw]] has been introduced. It allows to reduce memory footprint at the expense of CPU time.

Finally, a bug has been removed (when all KB energies are negative), and a test introduced [[test:v9_145]].

By Miquel Royo, Asier Zabalo and Massimiliano Stengel (MR913).

<a name="v9.10.B.3"></a>
**B.3** Linear response computation of the U and J parameters

The old utility "ujdet" to compute the U and J parameters in DFT+U with the linear response method [[cite:Cococcioni2005]]
has been replaced by the new "lruj" utility. The workflow is different.
The [[tutorial:lruj]] has been written, with three corresponding tests, [[test:lruj_1]], [[test:lruj_2]], [[test:lruj_3]].
See also the input variables [[pawujv]]. The tutorial and corresponding tests "ujdet" have been suppressed.
The tests v5_38, v5_39, v5_40, v6_41 have been suppressed, and replaced by [[test:v9_105]], 
[[test:v9_106]], [[test:v9_107]], [[test:v9_108]], [[test:v9_109]]. This is also documented in [[topic:CalcUJ]].

By Lorien Mac Enulty with help from David D. O'Regan (MR905, 912).

**B.4** Cumulant method for spectral function

The computation of the electronic spectral function with electron-phonon coupling included is now enabled using the cumulant method.
See [[cite:Nery2018]] and [[cite:Abreu2022]] and other related publications.

Activate it using [[eph_task]]=9 when [[optdriver]] == 7.
New input variable: [[tolcum]].
See the [[test:v9_60]].

By J. Abreu with help from M. Giantomassi (MR 907)


**B.5** Support for norm-conserving pseudopotentials in UPF2 format

Abinit can now read NC pseudos in UPF2 format (both scalar and relativistic version) thanks to the UPF parser imported from quantum espresso and an additional
routine used to convert FR pseudos from (j,kappa) to scalar + SOC term taken from oncvpsp.

The total energy computed with UPF pseudos does not perfectly agree with the one obtained with the corresponding psp8 pseudos.
Most of the difference originates from the value of epsatm $$ \int r^2 (V(r)+\frac{Zv}{r}) dr$$ as the local part in the UPF file is tabulated
on a much larger radial mesh. This should not represent a serious issue as long as total energy calculations are performed with the same pseudopotentials.
Forces, stress tensor and KS eigenvalues are in much better agreement in the systems investigated so far.

See the [[test:v9_130]] and [[test:v9_131]]

By M. Giantomassi (MR896)

**B.6** Initialization of the wavefunctions using atomic orbitals

For pseudopotentials that contain the information about atomic local orbitals, like the UPF2 format, the wavefunctions
inside ABINIT can be initialized from the Hilbert space spanned by such set of functions,
using the input variable [[wfinit]]=2.

See test [[test:v9_130]].

By M. Giantomassi (MR896)

**B.7** Temperature-dependent XC functionals (free energy), using libXC

The following temperature-dependent XC functionals from libXC are now available: 
LDA T-dependent functionals from [[cite:Karasiev2014]], with [[ixc]]=-269, from [[cite:Karasiev2018]],
with [[ixc]]=-318, and from [[cite:Groth2017]], with [[ixc]]=-577.
Previously, the IIT temperature-dependent Free Energy functional of [[cite:Ichimaru1987]], with [[ixc]]=50
had been coded, but not documented. Documentation is delivered in the present release.

See [[test:libxc_22]].

By M. Torrent (MR901)

**B.8** Atomic orbital magnetic moment inside PAW spheres

Implementation of atom-by-atom orbital magnetization integration inside the PAW spheres. 
x, y and z components are printed. Decomposition on p, d and f orbitals is also done. 
Works only for PAW+U+SOC (and nspden=4). 
Works also for orbitals where no U is specified. 
New input flag [[prt_lorbmag]]. See test [[test:v9_112]]. Mentioned in [[topic:AtomCentered]].

By A. Sasani & E. Bousquet (MR915).


**B.9** High-temperature DFT: Improvements of the Extended First-Principles Molecular Dynamic (ExtFPMD) calculations.

[[useextfpmd]]=1 now computes contributions using Fermi gas DOS (which was found to be more stable for pure and mixtures). 
Old [[useextfpmd]]=1 is now [[useextfpmd]]=4 (tests were changed accordingly)

[[useextfpmd]]=10 controls the Hybrid Thomas-Fermi / Kohn-Sham scheme see [[cite:Hollebon2022]].
This model aims at reducing further the needed number of bands at high temperature compared to Extended FPMD. 
No documentation is available since it is work in progress.

Added a new input variable [[extfpmd_nbdbuf]] which specifies the number of bands to use for the buffer if [[useextfpmd]] /= 0.
Among the total number of bands, last [[extfpmd_nbdbuf]] bands
occupation will be set to 0, and ExtFPMD model will take charge of computing
electronic contributions starting from [[nband]] - [[extfpmd_nbdbuf]].
In some cases, setting this input variable to a positive number can solve
convergency problems due to high variations of electron density within the SCF cycle.
Moreover, setting [[extfpmd_nbdbuf]] = [[nband]] should theoretically give
access to Fermi gas orbital free calculations (not tested yet).
This fix has been proposed on the forum by Thomas Gawne (University of Oxford, UK)

By A. Blanchet (MR883 and MR916)


<!--
**B.11** Interface to coupled-cluster CC4S calculations.

The writing of the file needed as input for computations with the CC4S package, <https://manuals.cc4s.org/user-manual>, 
allowing to perform coupled-cluster calculations (e.g. CCSD), perturbative triples (and more), can be activated using [[optdriver]]=6 and [[gwr_task]]="CC4S".
See test test:gwr_07 (not yet activated)..

By M. Giantomassi (MR 875, 907)
-->

* * *

### **C.** Changes for the developers (including information about compilers)

**C.1** Improvement of gfortran handling.

Previously Abinit did not add the specific flags for gfortran 12, similar to gfortran 11, because this new version was not anticipated in config/hints/ .
The logic has been changed in config/hints, the default being the newest version.
The old gfortran versions 7, 8 and 9 are treated as specific cases.
So, ABINIT is working with gfortran 12 & 13.

By F Bruneval, with adaptation to gfortran 12 by JM Beuken and to gfortran 13 by M Torrent (MR914, MR919),

**C.2** A new bot for memory profiling has been added to the test farm, named scope_gnu_12.2_mpich .

By JM Beuken (MR888)

* * *

### **D.**  Other changes (or on-going developments, not yet finalized)

**D.1** Low-scaling GW and RPA implementations
The implementation of a cubic scaling real space imaginary time algorithm for GW and RPA is on-going.
By M. Giantomassi (MR875, MR907)

**D.2** Interface to coupled-cluster CC4S calculations.

The implementation of writing a file needed as input for computations with the CC4S package, <https://manuals.cc4s.org/user-manual>, 
is working, but not yet in production.
By M. Giantomassi (MR 875, 907)

**D.2** Coulomb interaction with 2D cut-off is now working for the total energy and forces.
This has been tested agains Quantum Espresso implementation. However, stresses are still incorrect.
New test [[test:v9_132]].
By B. Guster, with help from X. Gonze (MR908).

**D.3** Implemented forces and stresses using "gemm" programming model.
This will later allow computing forces/stresses on GPU.
By M. Torrent (MR886 and 887).

**D.4**
Added [[prteig]]=2, in order to print EIG.nc file at each timestep (using already used for other variables TIMx suffix). 
(No test - should be added).
By A. Blanchet (MR916).

**D.5**
Allow for band-by-band decomposition of the STM density, using negative values of [[prtstm]].
See test [[test:v4_46]].
By X. Gonze (MR880).

**D.6**
Several improvements for recognition of parallel netcdf for macbookpro and the Zenobe Belgian supercomputer.
By M. Verstraete (MR876).

**D.7**
Improve the initialization of paral_kgb/wfoptalg/istwfk.
By M. Torrent (MR918).

**D.8**
New units are recognized by the input file parser: "meV" (for millielectron-volt);  "S", "Sec" or "Second"; "Kelvin".
By M. Giantomassi (commit 692a4ee0c6) and X. Gonze (commit 39801af30).

**D.9**
New tests of the band parallelism in DFPT: [[test:paral_65]] and [[test:paral_66]].
By M. Giantomassi (commit 31e8aa66d8).

**D.10** Improved developer documentation, section .
[How to add a new test](https://docs.abinit.org/developers/developers_howto/#how-to-add-a-new-test-in-the-test-suite).
By X. Gonze (commit dabc1b905).

**D.11** Fixed typo in CITATION.cff.
By P. Kesteneer (MR910). 

**D.12** New topic [[topic:AtomCentered]] created.
By X. Gonze (commit 425e8c)

**D.13** Improvements of tutorials base3.md and gw1.md in order to better avoid students to commit mistakes.
By X. Gonze (commits 1d56e983f and dfd207458) 

**D.14** In m_phgamma.F90, spin-resolved calculations for the case prteliash==3 did not work correctly 
since phonon linewidths were calculated for spin=1 only. spin>=2 values are filled by NaNs. This small addition fixes the issue.
Also, a minot format fix.
By F. Akhmetov (Radioteddy on Github). commit bd76768 on abinit github, but directly ported to the trunk/release-9.10 branch.

**D.15** Fix parser problem. The input would not be parsed correctly when more than one environment variable is present in the input file.
By M. Mignolet (MR 928 backported to ABINITv9.10)

**D.16** Improvements of documentation for spinmagntarget and occopt, in the case of ferromagnetic insulators.
Improvements of documentation for rfasr, asr and chneut. Fix timing issues for Fock.
Update doc about the change from npkpt to np_spkpt. Cross refer between U(J) tutorials
By X. Gonze (several commits)

* * *


## v9.8

Version 9.8, released on December 23, 2022.
List of changes with respect to version 9.6.
<!-- Release notes updated on March 15, 2023. -->

Many thanks to the contributors to the ABINIT project between
October 2021 and August 2022, and some late contributions up to April 2023 ! These release notes
are relative to modifications/improvements of ABINIT v9.8 with respect to v9.6.
<!-- Merge requests up to and including MR874. Also, MR881, 882, 885, 891, 892, 894, 897, 898, 899, 900, 902, 903, 911, are taken into account. -->

The list of contributors includes:
B. Amadon, G. Antonius, L. Baguet, S. Bandyopadhyay, L. Bastogne, J.-M. Beuken, J. Bieder, A. Blanchet, 
F. Bottin, J. Bouchet, E. Bousquet, F. Brieuc, V. Brousseau-Couture, N. Brouwer, F. Bruneval, M. Cote, 
C. Espejo, Ph. Ghosez, M. Giantomassi, O. Gingras, X. Gonze, B. Guster, P. Kesterner, 
R. Outerovich, Ch. Paillard, M. Royo, A. Sasani, B. Sataric, M. Schmitt, F. Soubiran, 
M. Torrent, M. Verstraete, He Xu, J. Zwanziger.

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

### **A.** Important remarks and warnings. Also, hotfixes for v9.8.3 (A.4 to A.10).

**A.1** Warning: the input variables prtefg and prtfc have been renamed [[nucefg]] and [[nucfc]].

By J. Zwanziger (MR850)

**A.2**
Within PAW in ABINIT, the ZORA relativistic factor for all PAW+spin-orbit coupling has been corrected:
A ^2 was missing for the 1/(1-(v/c)^2) factor.
This changes slightly all the PAW+SOC results (because the factor is very small), without any influence on physical results. 
However, previous results cannot be anymore obtained.

By M. Torrent (MR849)

**A.3**
The default value for [[rfdir]] is now (1 1 1), instead of (0 0 0).  
The one of [[rfatpol]] is now (1 [[natom]]), instead of (1 1).

By X. Gonze (MR852)

**A.4** The default values of dossmear (@anaddb) and dosdeltae (@anaddb and @atdep) have changed, to smaller values, to improve default accuracy.

By X. Gonze 

**A.5**
Correction and cleaning of DFT+U with magnetism ([[nspden]]=4), following the merge 881.
Introduce [[optdcmagpawu]] input to control different choices of DC term (for tests and code comparisons, not useful for production).
Versions before 9.8 is equivalent to [[optdcmagpawu]]=1 (no magnetism in the DC term). Now the default is 3 (magnetism in the DC term). Some refs are changed accordingly.
Change of the tests v9/76,77 and 78 for better precision. Add the tests v9/88 and 89 to tests the combination of PAW+U with different [[pawxcdev]].

By L. Baguet (MR898)

**A.6**
Some users have reported that with the new [[optcell]]=4,5 or 6 option, the calculation
continues when the criterion should be already reached. For example, with [[optcell]]=5 (relaxing b only), the
xx component of the stress could still be large but shouldn't be checked. This has been fixed.

By Xu He (MR897)

**A.7**
More fix on the generation of symmetry-adapted terms in Multibinit. A more complete set of terms are now generated, with improved time and memory performance. 

By Xu He and A. Sasani (MR899)

**A.8**
m4 detection netcdf(-f) //: AC_RUN_IFELSE hangs with some compilers then switch to AC_LINK_IFELSE

By JM Beuken (MR900)

**A.9**
Several improvements for external libs: FFTW3 thread safety, openBLAS multithreading, netCDF Fortran parallel

By M. Torrent, with patch from P. Kesteneer (MR902)

**A.10**
Several fixes, including documentation for icutcoul and related input variables

By. X. Gonze (MR903)

* * *

### **B.** Most noticeable achievements

**B.1** Lattice Wannier functions can be computed, using the SCDM-k algorithm, or the projected Wannier function algorithm.

The [[tutorial:lattice_wannier]] has been written to teach how to construct such lattice Wannier functions. 
They are used in localized bases for atomic distortions. 
One typical use case is to build an effective Hamiltonian of collective, localized, atomic displacements (see the next achievement). 

A script (compare_phbands.py) to compare phonon/LWF band structures is added to the scripts/post_processing directory.

Related input variables : 
[[lwfflag@anaddb]],
[[lwf_anchor_ibands@anaddb]],
[[lwf_anchor_proj@anaddb]],
[[lwf_anchor_qpt@anaddb]],
[[lwf_disentangle@anaddb]],
[[lwf_mu@anaddb]],
[[lwf_ngqpt@anaddb]],
[[lwf_nwann@anaddb]],
[[lwf_projector@anaddb]],
[[lwf_sigma@anaddb]].

Related topic [[topic:LWFModel]].
See tests [[test:lwf_1]], [[test:v9_110]], and [[test:v9_111]].

This feature is still under heavy development. The current version should be regarded as a "technology preview". 

By He Xu (MR844)

**B.2** Lattice Wannier function dynamics is available inside the second-principle engine MULTIBINIT.

Once Lattice Wannier functions are available, they can be used with different dynamical algorithm to deduce heat capacity, susceptibility, structural phase transition, critical temperature, instead of doing standard molecular dynamics with all atoms.
Related input variables :
[[lwf_constraint@multibinit]],
[[lwf_dt@multibinit]],
[[lwf_dynamics@multibinit]],
[[lwf_init_state@multibinit]],
[[lwf_init_hist_fname@multibinit]],
lwf_mc_avg_amp@multibinit,
[[lwf_nctime@multibinit]],
[[lwf_ntime@multibinit]],
[[lwf_pot_fname@multibinit]],
[[lwf_taut@multibinit]],
lwf_temperature@multibinit,
[[lwf_temperature_end@multibinit]],
[[lwf_temperature_nstep@multibinit]],
[[lwf_temperature_start@multibinit]],
[[lwf_var_temperature@multibinit]].

See the tutorial [[tutorial:lwf_model]] and related tests.

This feature is still under heavy development. The current version should be regarded as a "technology preview". 

By He Xu (MR851)

**B.3** Numerous miscellaneous improvements of the second-principle engine MULTIBINIT.

Hybrid Monte-Carlo Mover with NPT ensemble ([[ionmov]]=25).

MULTIBINIT can now be used without 'files' file, as the main ABINIT or ANADDB. 
Related input variables [[latt_pot_fname@multibinit]], [[latt_harm_pot_fname@multibinit]], 
[[latt_anharm_pot_fname@multibinit]], [[latt_training_set_fname@multibinit]], 
[[latt_test_set_fname@multibinit]], [[spin_pot_fname@multibinit]], [[spin_init_hist_fname@multibinit]], [[slc_pot_fname@multibinit]],
[[outdata_prefix@multibinit]].

The MULTIBINIT tutorial has been improved. In particular, it is now starting with a global introduction ([[tutorial:multibinit]]).  

The following MULTIBINIT features and input variables have been introduced :
define oblique supercells ([[ncellmat@multibinit]]), print Goal-Function values in CSV format ([[prt_GF_csv@multibinit]]), 
impose the seed for MULTIBINIT spin/LWF dynamics to obtain reproducible results ([[randomseed@multibinit]]),
specify three weights for Energy, Forces and Stresses in the calculation of the Goal Function ([[bound_factors@multibinit]]),
specify three weights for Energy, Forces and Stresses in the calculation of the Goal Function during the fit process ([[fit_factors@multibinit]]),
specify three weights for Energy, Forces and Stresses in the calculation of the Goal Function during the optimization process ([[opt_factors@multibinit]]),
specify the relative penalty for the determination of bounding coefficient values ([[bound_penalty@multibinit]]),
activate the generation of pure displacement coefficients ([[fit_dispterms@multibinit]]), 
specify the number of anharmonic coefficients per symmetric irreducible atom to add during fit process ([[fit_ncoeff_per_iatom@multibinit]]),
specify the number of coefficients imposed with fixed value as in the input xml during the fit process for the mode
([[fit_nimposecoeff@multibinit]]),
specify the indices of the imposed coefficients with fixed coefficient value during the fit process for the model ([[fit_imposecoeff@multibinit]]),

See the tests in which these input variables are used. 

By He Xu, M. Schmitt, A. Sasani, L. Bastogne, S. Bandyopadhyay, and P. Ghosez (MR812, 851, 868, 894)


**B.4** The TDEP formalism implemented in ABINIT (aTDEP), allowing to compute temperature-dependent phonon band structures,
 has been made more robust, and tested extensively. One tutorial ([[tutorial:atdep1]]) is now available.
See the thirty-seven tests from [[test:atdep_01]] to [[test:atdep_37]] and the tests mentioned in the 
tutorial [[tutorial:atdep1]]. Related publication, see [[cite:Bottin2020]].

By F. Bottin, J. Bieder and J. Bouchet (MR 836).


**B.5** 
The conducti utility can treat Spin-Orbit Coupling for transport properties (within PAW) : conductivity, XANES, transport coefficients, ...
See [[cite:Brouwer2021]].
The writing of documentation and tutorial is in progress.

By M. Torrent and N. Brouwer (MR849).

* * *

### **C.** Changes for the developers (including information about compilers)

**C.1** Added support for NAG 7.1

From J.-M. Beuken (MR830).

**C.2** Update build system to allow the use of NVTX library, providing profiling annotations (only when gpu is enabled). 
This makes more readable profiling and tracing information when viewed with nsys-ui. 
Add new parameter [[use_nvtx]] to enable/disable nvtx annotations at runtime. 
If abinit is built without gpu, annotations completely vanish at compile time.

From P. Kestener (MR843)

**C.3** Improve detection of inlined macros. The developers should now use 

    ABI_SFREE(allocateble_array)

instead of

    if(allocated(allocatable_array)) ABI_FREE(allocatable_array)

From M. Giantomassi (MR859)

**C.4** The DDB IO routines have been refactored throughout the different main codes
(respfn, gstate, anaddb, nonlineal, longwave, ddb_interpolate, gruns_new, thmeig).
The ddb merging routines have been refactored (merge_ddb replaces mblktyp1 and mblktyp5).
New MPI treatment of ddb reading (no more free-for-all reading).
Removed several arguments of ddb_from_file: natom, natifc and atifc.
Moved routine dfptnl_doutput from m_ddb to m_nonlinear. Remove dfpt_lw_doutput .

From G. Antonius (MR872)

**C.5** Suppressed CHILDREN and PARENTS sections in ROBODOC header.
They were not maintained automatically anymore, so many had become misleading.

From X. Gonze (MR874)

**C.6**  
A new type of file 'GSTORE' has been introduced,  for the electron-phonon matrix element storage, where it is taken advantage
of filters (on energy or band or wavevectors) to reduce the size compared to the more usual EIG1 file type.
It contains also the related metadata.
Related input variables : [[getgstore_filepath]], [[gstore_cplex]], [[gstore_with_vk]], [[gstore_kzone]], [[gstore_qzone]],
[[gstore_kfilter]], [[gstore_brange]], [[gstore_erange]].

By M. Giantomassi (MR870)


* * *

### **D.**  Other changes (or on-going developments, not yet finalized)

**D.1** New tutorial on the use of the Z2pack postprocessor ([[tutorial:z2pack]]).
In this tutorial, the topological transition from Z2 trivial to Z2 non-trivial under pressure is reproduced. 
A test has been added but one needs to install z2pack to test it. See doc/tests/tutoplugs/z2.py, and [[tutorial:z2pack]].

From O. Gingras, V. Brousseau-Couture and M. Cote (MR 871)

**D.2** Improved the Wannier90 tutorial ([[tutorial:wannier90]]).
There is a new part, that describes projecting the band structure of La$_2$CuO$_4$ to a single orbital 
($d_{x^2-y^2}$) Hamiltonian. 
This is the first step in order the study the Mott transition in La$_2$CuO$_4$ using DFT+DMFT. 
From this step, one can use TRIQS to study the Mott transition.

From O. Gingras (MR 871)

**D.3** Make abinit compile and run with libxc v6

From M. Torrent (MR885)

**D.4** Modified [[optcell]]=4,5,6 to allow for relaxation of a vectors length and angle without constraining it to be orthogonal to the three others

From C. Paillard (MR858)

**D.5** New input variable for Optic, [[nband_sum@optic]], allowing to select the maximal number of bands included. This is convenient for convergence studies.

From M. Giantomassi (MR817)

**D.6** Implementation of Chebyshev filtering algorithm, version 2.

From B. Sataric, J. Bieder, and M. Torrent (MR 826)

**D.7** Miscellaneous improvements of the iterative Boltzmann transport equation coding. Input variable [[ibte_alpha_mix]].

From M. Giantomassi (MR821)

**D.8** Improvements related to electron-phonon interaction.

Miscellaneous improvement of the electron-phonon part of ABINIT (documentation, bug fixes, improved parallelism)

Work in progress : a new tutorial [[tutorial:eph4isotc]] 
to demonstrate the computation of superconducting properties within the isotropic Eliashberg formalism.
See tests in the [[tutorial:eph4isotc]].

By M. Giantomassi (MR870)

**D.9** Improvements of the cRPA determination of the U and J parameters (default keywords, tests and tutos). 

From R. Outerovich (MR835)

**D.10** Work on Real-time Time-Dependent Density Functional Theory implementation within ABINIT.

From F. Brieuc (MR853)

**D.11** Test of the Zero-point renormalization for hexagonal systems (Frohlich generalized model). See [[test:v8_60]].

From B. Guster (MR815)

**D.12** Implement [[chksymtnons]]=3 : FFT grid and spatial symmetry operations are coherent.

From X. Gonze (MR828)

**D.13** Improvement of VdW-DF.
Corrections to the implementation of vdW-DF non-local functional found in files 56_xc_/m_xc_vdw.F90 and 98_main/vdw_kernelgen have been done, also several debugging lines have been included. From a careful comparison of the computed quantities from a pre-calculated density and gradient obtained with Siesta, it has been observed that Abinit is getting the correct numbers up to the final 3D FFTs which still present differences that lead to incorrect values for the vdW-DF correlation energy.

From C. Espejo (MR829)

**D.14** 
Make use of gvnlxc optional in getghc, which allows memory savings in lobpcg2 and chebfi2. Could be useful in other parts of the code.

From L. Baguet (MR831)

**D.15**
Miscellaneous changes in DMFT: keyword for Wannier orthonormalisation, 
implementation of calculation of the weight of configuration in CTMQC, 
double counting for charge only DFT+DMFT ([[dmft_dc]]=6), work in progress concerning alternate calculation of electronic entropy in DMFT. 

From B. Amadon and R. Outerovich (MR833) 

**D.16**
Move DDK reading outside of loop for non var matrix element calculations. Should be much more efficient IO.

From M. Verstraete (MR840)

**D.17**
Use wfdgw_t subclass in GW/BSE code. This is needed so that the wfd in EPH does not allocate bks_tab whose size scales badly with nprocs and nkibz.
 
From M. Giantomassi (MR841)

**D.18**
Add spinat to GSR.nc

From M. Giantomassi (MR842)

**D.19** Orbital magnetism progress 

From J. Zwanziger (MR847)

**D.20** Fix [[prtwf]] and [[prtpot]] in DFPT 

From M. Giantomassi (MR848).

**D.21** Improved ABINIT+TRIQS python invocation interface.

From O. Gingras (MR851)

**D.22** Bug fixes for PAW+Hybrid

From F. Bruneval and F. Soubiran (MR854)

**D.23** Improvements of the Frohlich model implementation (e.g. dielectric average decomposition).

From B. Guster (MR860)

**D.24** Bug fix of DFT+U in the non-collinear case

From E. Bousquet (MR881)

**D.25** GPU coding : inverse overlap matrix, and non-local operator

From P. Kestener (MR843 and 869)

**D.26** Restructuring of the tutorial index page, doci/tutorial/index.md ..

From X. Gonze

**D.27** A CITATION.cff file has been created. Also, a LICENCE file (pointing toward COPYING).

From X. Gonze

**D.28** Updated the tarball for the fallbacks

From JM Beuken (MR911)

**D.29** Improve the procedure to examine the convergence with respect to ecut and pawecutdg in tutorial PAW1.

From X. Gonze (20230424)

**D.30** Miscellaneous additional bug fixes, typos fixes, or upgrade of build system.

By F. Goudreault (MR816), M. Giantomassi (MR821 and 845), P. Kestener (MR827 and 843), 
A. Blanchet (MR832), C. Paillard (MR834), M. Verstraete (MR837),
M. Torrent (MR838 and 873), B. Seddon and X. Gonze (MR839 and 855), L. Baguet (MR857),
J.-M. Beuken (MR882).

* * *

## v9.6

Version 9.6, released on October 4, 2021.
List of changes with respect to version 9.4.
<!-- Release notes updated on November 9, 2021. -->

Many thanks to the contributors to the ABINIT project between
February 2021 and September 2021. These release notes
are relative to modifications/improvements of ABINIT v9.6 with respect to v9.4.
<!-- Merge requests up to and including MR814 except MR812, then also MR818, 819, 820 and 822 are taken into account. -->

The list of contributors includes:
L. Baguet, J.-M. Beuken, J. Bieder, A. Blanchet,
J. Clerouin, C. Espejo, M. Giantomassi, O. Gingras, X. Gonze, F. Goudreault,
B. Guster, Ch. Paillard,
Y. Pouillon, M. Rodriguez-Mayorga, M. Royo, F. Soubiran,
M. Torrent, M. Verstraete, J. Zwanziger.

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

### **A.** Important remarks and warnings.

(nothing to mention for this v9.6)

* * *

### **B.** Most noticeable achievements

**B.1** Band-parallel implementation of DFPT: the memory footprint is now distributed over different processors.
Previously, the memory was distributed only for k-point parallelism.
This is automatically managed, no user action is to be taken to activate this memory saving.

See test [[test:dfpt_04]].

By M. Verstraete (MR784, 803)

**B.2** The Iterative Boltzmann Transport Equation (IBTE) to compute the electric conductivity has been implemented.
To activate the IBTE, use [[ibte_prep]] = 1 with [[eph_task]] -4.
The IBTE solver can also be invoked in standalone mode by providing a SIGEPH file with [[eph_task]] = 8.
Related input variables: [[ibte_niter]], [[ibte_abs_tol]] and [[ibte_alpha_mix]].
See test [[test:v9_65]].

By M. Giantomassi (MR794)

**B.3** The computation of dynamical quadrupoles and flexoelectricity is now available within the GGA.
Test for GGA + longwaves [[test:v9_46]].

Also, the usage of the quadrupoles has been rationalized (and made easier) in anaddb
as the default value of [[dipquad@anaddb]] and [[quadquad@anaddb]] has been changed to 1.
This means that dipole-quadrupole and quadrupole-quadrupole contributions are always included
in the Fourier interpolation of the dynamical matrix provided the DDB provides these terms.

This "default behaviour" is similar to the one used for the dipole-dipole treatment.
Indeed, the default value of [[dipdip@anaddb]] is 1 hence the dipolar term is automatically included
if the DDB contains the Born effective charges and the electronic dielectric tensor.
Still, the user can deactivate the inclusion of the different terms by setting the corresponding
variable to zero for testing purposes.
See the ANADDB input variables and test [[test:lw_6]]

By M. Royo with contribution by M. Giantomassi for the change of default (MR795)


**B.4** Stresses are available within cDFT (constrained DFT).
See tests [[test:v9_01]], [[test:v9_02]] and [[test:v9_03]].

By X. Gonze (MR802)


**B.5** The computation of effective mass renormalization due to electron-phonon coupling, treated in the generalized Frohlich model,
is now available, for cubic materials. An article has been submitted, see <https:arxiv.org/abs/2109.12594>.
Activate it using [[eph_task]]=10. 

See test [[test:v9_66]].

By B. Guster (MR800)

**B.6** Important speed-up of the PAW calculations is allowed thanks to the storage of "cprj" coefficients.
See the input variable [[cprj_update_lvl]]. However, at present this is only possible for ground-state
calculations, with several restrictions, spelled in [[cprj_update_lvl]]. So, this is not activated by default.
There is also an internal variable [[cprj_in_memory]] exposed in the documentation.
Other input variables have been introduced in the development process : [[fft_count]] and [[nonlop_ylm_count]].
They allow one to monitor better the number of FFTs and non-local operator applications.

See tests [[test:v9_71]], [[test:v9_72]], [[test:v9_73]] and [[test:v9_74]].

By L. Baguet (MR793).

**B.7** The Extended First-Principles Molecular Dynamics has been implemented.
This method allows one to drastically reduce the needed number of bands for high temperature simulations,
using pure single plane waves description based on the Fermi gas model beyond explicitly computed bands.
The implementation and usage are described in <https://doi.org/10.1016/j.cpc.2021.108215> (Authors: *A. Blanchet, J. Clérouin, M. Torrent, F. Soubiran*).

See [[topic:ExtFPMD]], as well as the input variables [[useextfpmd]] and [[extfpmd_nbcut]],
and test [[test:v9_92]].

By A. Blanchet, J. Clérouin, M. Torrent, F. Soubiran. (MR788).


* * *

### **C.** Changes for the developers (including information about compilers)

**C.1** Supported compilers

* gfort (GNU) compiler: v11 newly supported.
* ifort (Intel) compiler: v21.4 newly supported.
Two new bots introduced in the test farm : alps_intel_21.4_elpa and graphene_gnu_11.2_macports .

By JM Beuken

* * *

### **D.**  Other changes (or on-going developments, not yet finalized)

**D.1** New input variable for "optic": [[prtlincompmatrixelements@optic]].

Added this flag in order to make it possible to print the different elements that are used to build the susceptibility of the linear component of the dielectric tensor.
These elements are namely: the matrix elements, the renormalized electronic eigenvalues, the occupations and the kpt weights.
Everything is dumped into the _OPTIC.nc file by the main process. Thus optimization could be done memory-wise and speed wise if MPI-IO is implemented for this nc file.

[[test:v9_49]] was created which is the same as [[test:v9_48]] except with the aforementioned flag set to 1.
This test checks that everything works well even though we print the matrix elements.
It does not test that matrix elements are well printed because that would require testing of the OPTIC.nc file.
Although it is possible to check that it works well using a simple python script (see the figure in the merge request on Gitlab).
(Note that the tests v9_13 and v9_14 have been moved to v9_47 and v9_48 in this change).

By F. Goudreault (MR776)

**D.2** New radial sine transform for the vdW-DF kernel.

By C. Espejo (MR 797)


**D.3** New test of orbital magnetism, [[test:v9_37]].
Also, on-going work on orbital magnetism, including use with DDK wavefunctions.

By J. Zwanziger (MR767, MR775, MR779 and MR787)

**D.4** Migration to mkdocs==1.1.2 and  mkdocs-material==7.0.6.
mksite.py now requires python >= 3.6 .
Activated search capabilities, available in the new mkdocs version.

By M. Giantomassi (MR774)

**D.5** Fixed bug in make_efg_onsite for [[nspden]]=2 case.

By J. Zwanziger (MR783)

**D.6** Correction of tutorials Rf1 and Rf2 for version 9

By O. Gingras (MR785)

**D.7** Fixed errors and bugs detected by using -ftrapuv intel option

By M. Giantomassi (MR789)

**D.8** Bug fix in [[nspden]]=4 DFPT for Fe

By M. Verstraete (MR790)

**D.9** Fixed a spurious test line 711 of m_occ.F90 that caused abinit to abort in the case of [[occopt]]=9,
if the number of conduction bands was enough to accommodate nqFD but not enough to accommodate nelect.

By Ch. Paillard (MR791)

**D.10** GW methodology with Kohn-Sham density matrix.
Solving a bug producing a segmentation fault when using [[bdgw]] and [[gw1rdm]].
New test [[test:v9_37]].

By M. Rodriguez-Mayorga (MR792)

**D.11** Introduced new input variable use_oldchi.
This input variable is temporary, for testing purposes. It is documented, but not tested.

By Wei Chen (modified line 743 in src/95_drive/screening.F90 on 23 April 2021).

**D.12** The input variable [[rfstrs_ref]] has been introduced, but not yet documented and tested, as this is on-going work.

By M. Royo 


**D.13** Miscellaneous additional bug fixes, or upgrade of build system.
in the upgrade of tutorials).
By J. Bieder, M. Giantomassi, Y. Pouillon, M. Torrent, J. Zwanziger.

* * *

## v9.4

Version 9.4, released on February 25, 2021.
List of changes with respect to version 9.2.
<!-- Release notes updated on April 30, 2021. -->

Many thanks to the contributors to the ABINIT project between
November 2020 and April 2021. These release notes
are relative to modifications/improvements of ABINIT v9.4 with respect to v9.2.
<!-- Merge requests up to and including MR766 are taken into account, also MR768 (backported) up to MR772 and MR780, 781, 782. -->

The list of contributors includes:
B. Amadon, L. Baguet, J.-M. Beuken, J. Bieder, E. Bousquet, V. Brousseau, F. Bruneval,
W. Chen, M. Cote, M. Giantomassi, O. Gingras, X. Gonze, F. Goudreault,
B. Guster, T. Karatsu, A. H. Larsen, O. Nadeau, R. Outerovich, Ch. Paillard, G. Petretto,
S. Ponce, Y. Pouillon, G.-M. Rignanese, M. Rodriguez-Mayorga, M. Schmitt,
M. Torrent, M. Verstraete, He Xu, J. Zwanziger.

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

### **A.** Important remarks and warnings.

**A.1** The [[charge]] variable is obsolete, and has been replaced by [[cellcharge]]. Indeed, [[charge]] was quite ambiguous,
and the string `charge` present in some other input variables. For the time being, ABINIT still recognizes [[charge]]
in the input file, but this might not last longer than in ABINITv9.

**A.2** There is a new check, governed by the input variable [[chksymtnons]], to examine
whether the [[tnons]] of all symmetry operations
is zero or a rational number with small denominator, which is required for GW calculations as implemented in ABINIT.
It is always possible to choose
the origin of coordinate with such properties, and ABINIT can gives suggestions. If you do not want to change
your coordinate origin (e.g. you have no intention to perform a GW calculation), set [[chksymtnons]] to zero,
or (but this is more dangerous) set the meta-variable [[expert_user]] to one to disable several checks of input variables at once.

By X. Gonze (MR712)

**A.3** The input variable npkpt has been changed to np_spkpt . Indeed the parallelism governed by npkpt was about spin and k points,
not only k points. For the time being npkpt is still admitted, but will become obsolete at the next major version change.

By X. Gonze

**A.4** When [[nimage]]>1, the default value of [[prtgsr]] is now 0, like for several prt* variables.

By X. Gonze

**A.5** The code does not stop anymore at the first occurence of overlap between PAW spheres being larger than [[pawovlp]]
in case of [[ionmov]]/=0 or [[imgmov]]/=0, but only at the second occurrence per dataset. Indeed, such trespassing might only be transient.
See the description of [[pawovlp]].

By X. Gonze

* * *

### **B.** Most noticeable achievements

**B.1** The RMM-DIIS algorithm has been implemented.
This SCF (ground-state) algorithm is faster, but potentially more unstable,
than the CG or LOBPCG algorithms, for medium to large size systems,
as it has less cubic scaling steps (e.g. orthogonalisation). Typically used for molecular dynamics
or structural relaxations as the restart from the previous time step gives RMM-DIIS less opportunities to fail.
See input variables [[rmm_diis]] and [[rmm_diis_savemem]].
Several tests exist ([[test:paral_32]], [[test:paral_63]], [[test:paral_64]], [[test:v9_29]], [[test:v9_30]])
covering many cases, including NC/PAW and spin-orbit.
Note that the PAW version of RMM-DIIS is more unstable than the NC one and extra operations are needed to make it convergence.
So the speedup for PAW calculations is not as good as the one observed for NC.

By M. Giantomassi (MR757, MR719, MR718)

**B.2** The treatment of quasi-Fermi energies in the valence and conduction band,
with populations of electrons (in the conduction bands) and holes (in the valence bands)
has been implemented (gapped materials only, of course).
This has been used e.g. in [[cite:Paillard2019]].
See the variables [[occopt]]=9, and [[nqfd]].
See also the related input variable : [[ivalence]].
Internal variables ne_qFD and nh_qFD are presently initialized to [[nqfd]], which is NOT INTERNAL.
See test [[test:v9_91]].

By Ch. Paillard (MR755).

**B.3** All the tutorials have been carefully reexamined and improved, when appropriate.
In particular:

- the old pseudopotentials have been replaced by new ones from e.g. [pseudodojo](http://www.pseudo-dojo.org/) or [JTH](https://www.abinit.org/psp-tables);
- the text of the tutorial uses the new convention for launching abinit (e.g. `abinit input_file` instead of `abinit < files_file`) and the pseudopotentials are mentioned in the input file;
- the input file suffix has been changed from `.in` to `.abi`and the output file suffix has been changed from `.out`to `.abo`;
- the input files have been cleaned when adequate, and many have been restructured using a template;
with populations of electrons (in the conduction bands) and holes (in the valence bands)

<!--
Also, a new tutorial, [[tutorial:eph4isotc]], is available (with tests [[test:eph4isotc_1]] to [[test:eph4isotc_4]],
-->
Also, [[tutorial:nlo]] and [[tutorial:eph4zpr]] have been enlarged to new developments
(see [[test:eph4zpr_8]] and [[test:nlo_6]]).

By B. Amadon, L. Baguet, J. Bieder, E. Bousquet, F. Bruneval,
W. Chen, M. Cote, O. Gingras, M. Giantomassi, X. Gonze, F. Goudreault,
B. Guster, O. Nadeau, R. Outerovich, S. Ponce, M. Schmitt,
M. Torrent, M. Verstraete, He Xu, J. Zwanziger (numerous MRs)

**B.4** The GW 1-body reduced density matrix (1RDM) from the linearized Dyson equation has been implemented.
Its effect on the Hartree-Fock expectation values and therefore on the GW quasiparticle energies can be evaluated.
The resulting total energy parts, kinetic energy (including correlation), electron-nucleus, Hartree, Exchange, can be calculated.
Together with the Galitskii-Migdal correlation, it gives a new approximation the self-consistent GW total energy.
See input variables [[gw1rdm]], [[x1rdm]], also [[irdchkprdm]], [[prtchkprdm]] and [[gwgmcorr]].
See tests [[test:v9_33]] to [[test:v9_36]].

Also, some missing tests have been added:
- GW calculations based on Hartree-Fock wavefunctions can use mini Brillouin Zone integration technique, see [[test:v9_31]].
- A new test [[test:v9_40]] has been provided for the computation of the susceptibility matrix
$\chi_0$ with [[inclvkb]].

By Mauricio Rodriguez-Mayorga and F. Bruneval (MR722).

**B.5** The pSIC (polaron self-interaction corrected) methodology has been implemented.
See [[cite:Sadigh2015]] and [[cite:Sadigh2015a]]. This is based on the `images` capability
of ABINIT, that has been extended to different values of the input variable [[cellcharge]]
for different images, and also parallelized. To activate pSIC, use [[imgmov]]=6 with the proper occupation numbers.
See the test examples [[test:v9_22]], [[test:psic_01]], [[test:psic_02]] and [[test:psic_03]].

By X. Gonze (initial test from C. Tantardini) (MR770).

**B.6** The computation of the electric conductivity has been implemented for metals
in the relaxation-time approximation with transport lifetimes computed from the imaginary part of the Fan-Migdal self-energy.
See tests [[test:v9_62]] to [[test:v9_65]].

By O. Nadeau (MR756, MR716)

**B.7** Implementation of the  i-pi client-server protocol as described in [[cite:Kapil2019]].
This option requires [[ionmov]] 28 and the specification of the socket via command line options.
For UNIX socket, use: --ipi {unixsocket}:UNIX .
For INET socket, use  --ipi {host}:{port} .
Usage example:

     abinit run.abi --ipi {unixsocket}:UNIX > run.log

Note that, at present, this feature is mainly used to interface ABINIT
with the ASE optimization routines. Moreover the user is responsible for creating an input
file with tuned tolerances to prevent Abinit from exiting when internal convergence is reached.
See examples available in the [ASE documentation](https://wiki.fysik.dtu.dk/ase/dev/ase/calculators/socketio/socketio.html)

By M. Giantomassi and A. H. Larsen.


* * *

### **C.** Changes for the developers (including information about compilers)

**C.2** Test farm: new and obsolete bots

* Bots introduced in the test farm: scope_gnu_10.2_paral
* Bots removed: cronos2 (replaced by scope_gnu_10.2_paral)

Bigdft tests have been activated on ALPS.

By JM Beuken

**C.3** Supported compilers

* gfort (GNU) compiler: v10 newly supported, v5 obsolete
* ifort (INTEL) compiler: v15 obsolete (but to be reintroduced for licence reasons)

Support for AOCC has been added in the build system.

By JM Beuken

* * *

<a name="v9.4.D.1"></a>
### **D.**  Other changes (or on-going developments, not yet finalized)

**D.1** Calculation of Luttinger parameters (in the Frohlich model) and echo (see [[test:v8_57]]).
By V. Brousseau (MR736)

**D.2** New test [[test:v9_90]] of the treatment of the Coulomb interaction for low dimensional materials (0D and 2D).
By B. Guster.

**D.3** DFPT (including ddk perturbation) can now be done in the presence of [[nucdipmom]].
By J. Zwanziger (MR749)

**D.4** Bug fix and new test [[test:v9_43]] for the use of ANADDB in the presence of a large [[tolsym]] value.
By G. Petretto

**D.5** Several bug fixes related to the treatment of inaccurate atomic positions (and large tolsym).
Several test have been created ([[test:v9_17]] to [[test:v9_20]]).

**D.6** AiiDA+ABINIT developments

  - A AiiDA plugin for Abinit has been developed: <https://github.com/sponce24/aiida-abinit>, also indexed at <https://aiidateam.github.io/aiida-registry/>.
  - AiiDA is now supporting psp8 type pseudopotentials, <https://github.com/aiidateam/aiida-pseudo>. This also implied modifications of the
    [pseudodojo](http://www.pseudo-dojo.org), that now includes .djrepo for each type of pseudopotential.
  - Work on a [common relaxation workflow](https://github.com/aiidateam/aiida-common-workflows) for a dozen of codes, including ABINIT.

By S. Ponce, also with G.-M. Rignanese, G. Petretto, M. Giantomassi.

**D.7** The new input variable dmft_wanorthnorm has been introduced, see [[test:v6_07]] and [[test:v6_46]]. However, it should still be documented.
By B. Amadon.

**D.8** Increase stack size limit inside xmpi_init using POSIX C-API
By M. Giantomassi. MR 770.

**D.9** Document i-pi interface with links to ASE docs.
By M. Giantomassi. MR 770.

**D.10** Correction (from a message on the forum) related to the forces in electron-positron mode.
By M. Torrent. MR 780

**D.11** Miscellaneous additional bug fixes, improvements of documentation including for the build system (many other were made
in the upgrade of tutorials)..
By B. Amadon, L. Baguet, F. Bruneval, T. Karatsu, G. Petretto, Y. Pouillon, M. Torrent, J. Zwanziger.

* * *

## v9.2

Version 9.2, released on September 30, 2020.
List of changes with respect to version 8.10.
Release notes updated on November 10, 2020.

Many thanks to the contributors to the ABINIT project between
October 2018 and November 2020. These release notes
are relative to modifications/improvements of ABINIT v9.2 with respect to v8.10.
Merge requests up to and including MR692 are taken into account, also MR 697-702, 705, 707-710, 712, 715.

The list of contributors includes:
B. Amadon, G. Antonius, L. Baguet, J.-M. Beuken, J. Bieder, J. Bouchet, E. Bousquet, F. Bruneval, G. Brunin, Wei Chen,
J.-B. Charraud, Ph. Ghosez, M. Giantomassi, O. Gingras, X. Gonze, F. Goudreault,
B. Guster, G. Hautier, Xu He, N. Helbig, F. Jollet,
H. Miranda, F. Naccarato, R. Outerovitch, G. Petretto, N. Pike, Y. Pouillon, F. Ricci, M. Royo,
M. Schmitt, M. Stengel, M. Torrent, J. Van Bever, M. Verstraete, J. Zwanziger.

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

### **A.** Important remarks and warnings.

**A.1** At the occasion of the switch from ABINITv8 to ABINITv9, many improvements of the formats and content of files written
    by ABINIT have been made, so the backward compatibility of ABINITv9 may be broken.

In particular:

1. The build system relies on new `.ac9` files (see [B.6](#v9.2.B.6)), superceeding the v8 `.ac` files.
   A bash script (`upgrade-build-config-file.sh`) located in the top level directory of the package can be used
   to convert from the old `.ac`format to `.ac9`.
2. The build system of ABINITv9 does not build anymore the hard dependencies (Linalg, NetCDF4, HDF5, LibXC, ...),
   as this was not sustainable (see [B.6](#v9.2.B.6)) and nowadays most users install prerequisite libraries themselves.
   See also the specialized INSTALL notes for
   [CentOS](/INSTALL_CentOS), [EasyBuild](/INSTALL_EasyBuild), [MacOS](/INSTALL_MacOS), and [Ubuntu](/INSTALL_Ubuntu).
3. The main ABINIT output file now contains sections written in YAML (sometimes replacing text sections, sometimes adding information).
   This means that some user-developed parsing tools might not work anymore,
   and should be adapted to the new ABINITv9 output file (see [B.9](#v9.2.B.9)).
   Note that the YAML output is still under development and modifications may appear in the next versions.
   A python API to extract the results of the calculation will be provided when the implementation is finalized.
4. Several default values have been changed, see [A.3](#v9.2.A.3).


**A.2**
A new account of the ABINIT effort has been published in Computer Phys. Comm. [[cite:Gonze2020]].
It provides description of several new features.
A version of this paper that is not formatted
for Computer Phys. Comm. [is also available](https://www.abinit.org/sites/default/files/ABINIT20.pdf).
The licence allows the authors to put it on the Web.

A second new account of the ABINIT effort has been published in J. Chem. Phys. [[cite:Romero2020]].
The scope of this second paper is different from the first one. It is more a survey of ABINIT,
focusing on its specific capabilities. Still, it contains also some description of some new features.
A version of this paper that is not formatted for J. Chem. Phys.
[is also available](https://www.abinit.org/sites/default/files/ABINIT20_JPC.pdf).
The licence allows the authors to put it on the Web.

Other specific publications are mentioned in the [Suggested acknowledgment page](/theory/acknowledgments).

<a name="v9.2.A.3"></a>
**A.3**  The default values of the following ABINIT input variables have been changed:
    [[ixcrot]], [[chneut]], [[ntime]], [[prtkden]], [[symsigma]] and [[tolsym]]. In particular the new default value
    of [[tolsym]], 1e-5, is more in line with the tolerances of other codes, so that for users of such
    codes, one barrier to the use of ABINIT is removed. By the same token, some bug in the recognition of symmetries
    has been fixed, when [[tolsym]] is close to the default, see the new tests [[test:v9_15]] and [[test:v9_16]].
    The new input variable [[chksymtnons]] has been introduced, to govern the possible automatic alignment
    of the [[tnons]] with the FFT grid (actually needed for GW calculations).
    By X. Gonze (MR 689 and others)

**A.4** The initialization of the wavefunctions when [[paral_kgb]]=1 and [[nspinor]]=2 has been changed, since the previous one could prevent the code to converge.
    By M Torrent (MR 562).

**A.5** The input variable xangst has been disabled. Use [[xcart]] instead, and specify the unit, namely Angstrom.

**A.6** Work is on-going concerning the Coulomb singularity treatment, see [D.32](#v9.2.D.32). The usage of the input variable [[icutcoul]] is changing.
For the time being, use [[gw_icutcoul]] instead.

**A.7** The name of the t-DEP main executable has been changed from `tdep` to `atdep`, in line with [[cite:Romero2020]].
By J. Bieder (MR 642, 641).

* * *

### **B.** Most noticeable achievements

**B.1** Electron-phonon interaction (mobilities in the self-energy relaxation time approximation,
temperature-dependent electronic band structures including the zero-point renormalization, etc.)

The new capabilities of ABINITv9 related to electron-phonon calculations are described
fully in the Sec. 3.3.2 of [[cite:Gonze2020]], as follows.

>   In abinit v9, it is possible to compute the EPH self-energy
>   in the Kohn–Sham representation using the EPH matrix
>   elements. The code employs optimized algorithms to compute
>   either the full self-energy (needed for QP corrections and spectral
>   functions) or just the imaginary part that is then used to evaluate
>   mobilities within the self-energy relaxation time approximation
>   (SERTA). The computation of the mobility is fully
>   integrated inside abinit, and is an automatic output of the
>   computation of the imaginary part of the self-energy, bypassing
>   the need to post-process results. When computing the full self-energy,
>   it is possible to reduce the number of empty states
>   required for convergence by using the first-order wavefunctions
>   obtained by solving the relevant Sternheimer equation.
>
>   In the case of lifetime computations, the code takes advantage of the
>   tetrahedron method to filter contributing q-points, a double-grid
>   integration technique to accelerate the convergence at marginal
>   additional computational cost, and samples the relevant regions
>   in the Brillouin zone contributing to transport properties thus
>   leading to a significant reduction of the computational effort.
>   Crystalline symmetries are used throughout the code in order to
>   reduce the number of k- and q-points that must be explicitly
>   included in the integrals. To achieve good parallel efficiently, the
>   most CPU demanding parts are parallelized with MPI employing a
>   distribution schemes over k/q-points, perturbations and bands (the
>   band level is available only when computing the full self-energy).

Moreover, the interpolation of the DFPT potential, described in Sec. 3.3.1 of [[cite:Gonze2020]] is fully operational,
with many tests, and three tutorials provided.

List of tests: [[test:v8_44]], [[test:v9_50]], [[test:v9_53]], [[test:v9_56]], [[test:v9_60]], [[test:v9_61]],
[[test:eph4mob_1]], [[test:eph4mob_2]], [[test:eph4mob_3]],
[[test:eph4mob_4]],
[[test:eph4mob_5]],
[[test:eph4mob_6]],
[[test:eph4mob_7]],
[[test:eph4zpr_1]],
[[test:eph4zpr_2]],
[[test:eph4zpr_3]],
[[test:eph4zpr_4]],
[[test:eph4zpr_5]],
[[test:eph4zpr_6]],
[[test:eph4zpr_7]].

New input variables: [[brav]], [[dvdb_add_lr]], [[dvdb_qcache_mb]], [[dvdb_qdamp]],
[[dvdb_rspace_cell]], [[eph_doping]],
[[eph_phrange]], [[eph_tols_idelta]], [[eph_ecutosc]], [[eph_restart]],
[[eph_stern]], [[eph_use_ftinterp]], [[eph_phwinfact]],
[[getdvdb]], [[getdvdb_filepath]], [[getkerange_filepath]],
[[getsigeph_filepath]],
[[irddvdb]], [[prteliash]], [[rifcsph]], [[sigma_bsum_range]], [[sigma_erange]],
[[sigma_ngkpt]], [[sigma_nshiftk]], [[sigma_shiftk]], [[symv1scf]].

Note that the new EPH processing unit of ABINIT [[optdriver]]=7 has a different implementation than the one implemented in anaddb.
Three new tutorials are availables, [[tutorial:eph_intro]], [[tutorial:eph4mob]] and [[tutorial:eph4zpr]], and supercede the legacy tutorials
[[tutorial:eph_legacy]] and [[tutorial:eph_tdep_legacy]].
For further details about the implementation and usage, please consult [[cite:Brunin2020b]].

By G. Brunin, H. Miranda, M. Giantomassi, G.-M. Rignanese, G. Hautier.

**B.2** Flexoelectricity and dynamical quadrupoles

A new driver has been included in abinit that allows one to compute
4 spatial dispersion tensorial quantities: the clamped-ion flexoelectric tensor, the dynamical quadrupoles,
the first moment of IFC matrix and the first moment of the piezoelectric force response tensor.
Precalculation of ground state, first and second (d2_dkdk) order response functions is required.
After execution, the driver creates a 3rd order energy derivative database file
that is used by anaddb to compute the mixed and lattice-mediated flexoelectric tensors
or to include the dipole-quadrupole and quadrupole-quadrupole electrostatic interactions
in the calculation of the dynamical matrix.

See the complementary description
in the Sec. V. D of [[cite:Romero2020]], with underlying theory and test calculations
presented in [[cite:Royo2019]].
At the practical level, see [[cite:Romero2020]]:

>   In this way, both perturbations are generalized to finite q, as
>   is already the case for atomic displacements. This enables us
>   to carry out an analytical third order derivative of the energy
>   with respect to two of the standard perturbations, and to the
>   momentum q, which directly provides the sought-after spatial
>   dispersion tensors. Remarkably, by virtue of the 2n+1 theorem,
>   the third-order energies are computed in one shot using
>   precalculated first-order response functions to the standard
>   perturbations, without the necessity of self-consistently computing
>   any response function to a perturbation gradient. After
>   execution, the long-wave DFPT routines generate a derivative
>   database that is subsequently used by post-processing tools
>   implemented in ANADDB to compute and print the different
>   contributions to the FxE tensor.

>   The dynamical quadrupoles are the spatial dispersion counterparts of the Born effective charges,
>   and can be used in lattice dynamics calculations
>   to improve the prevalent dipole-dipole treatment of the
>   long-range interactions. The ANADDB routines that carry
>   out the process of interpolating the dynamical matrix following
>   Ref. 34 have been adapted to incorporate the dipole-quadrupole
>   and quadrupole-quadrupole electrostatic interactions
>   derived in Ref. 102. This new functionality results in a
>   faster convergence of the phonon bands calculation with respect
>   to the density of q points and, in some materials, represents
>   the only route to obtain the correct sound velocities.

>   Currently, the implementation is restricted to the use of
>   norm-conserving pseudopotentials without non-linear core corrections, and the LDA
>   functional.

A tutorial is in preparation, with tests [[test:lw_1]] to [[test:lw_7]].

See the [[topic:longwave]]. The relevant input variable is [[optdriver]]==10.
New input variables have been defined: [[lw_flexo]], [[lw_qdrpl]], [[prepalw]], [[flexoflag@anaddb]],
[[dipquad@anaddb]], [[quadquad@anaddb]].

This capability is still under development and not completely stable.
Interested users are strongly recommended to contact Miquel Royo (mroyo@icmab.es)
or Massimiliano Stengel (mstengel@icmab.es) before start using it.

By M. Royo, M. Stengel


**B.3** DFT+DMFT

The new capabilities of ABINITv9 related to DFT+DMFT calculations are described
fully in the Sec. 3.7 of [[cite:Gonze2020]], as follows.

>   The DFT+DMFT parallelism was improved for large
>   systems. In particular, it is now possible to parallelize the calculation
>   on both k-points and bands/g-vectors by using the input
>   variable [[paral_kgb]] = 1 and related input variables.
>
>   Two new approaches to CT-QMC have been added to
>   solve the AIM. In the first one, the density–density CT-QMC code
>   available in abinit [[cite:Gonze2016]], [[cite:Bieder2014]] was generalized in order to take into
>   account off-diagonal elements of the hybridization function. This
>   implementation is activated with the input variable [[dmft_solv]]
>   = 8. Spin–orbit coupling calculations are possible, but using a
>   real valued imaginary time hybridization function. This solver was
>   used in Refs. [[cite:Amadon2015]], [[cite:Amadon2016]].
>
>   In the second approach, we use the Toolbox for Research
>   on Interacting Quantum System (TRIQS)library [[cite:Parcollet2015]], which is an
>   open-source project that provides a framework for many-body
>   quantum physics and more specifically for strongly-correlated
>   electronic systems. TRIQS provides an open source implementation
>   of the continuous-time hybridization expansion quantum
>   impurity solver (CT-HYB) [[cite:Seth2016]], considered a state-of-the art
>   solver for multi-orbital AIM. An interface between abinit and
>   the impurity solver TRIQS/CT-HYB is now available and will make
>   use of the independent progress made by the TRIQS library. <...>

Also, the DMFT k-resolved spectral function is available (MR 529, 490).

List of tests: [[test:paral_84]], [[test:paral_86]], [[test:paral_99]], [[test:v8_01]].
New input variables: [[dmft_charge_prec]] and [[dmft_kspectral_func]] (test to be provided for the latter).
Also [[dmft_occnd_imag]], but only for keeping backward compatibility for tests.

By T. Cavignac, B. Amadon and O. Gingras.


**B.4** Spin model within Multibinit

The new capabilities of Multibinit within ABINITv9 are described
fully in the Sec. 4.1 of [[cite:Gonze2020]]. See also Sec. [D.1](#v9.2.D.1).
In particular, a spin model, described specifically in Sec. 4.1.2 of [[cite:Gonze2020]], is available, as follows.

>Multibinit implements the most commonly used model for spin systems,
>via the Heisenberg Hamiltonian including magnetic exchange and Dzyaloshinskii Moriya interactions.
>Single ion anisotropy and dipole–dipole interactions are also included,
>and all terms bear a very strong similarity to the quadratic part of the lattice model Hamiltonian.
>A number of open source spin dynamics codes already exist, such as UPPASD, VAMPIR, OOMF;
>the distinguishing features of multibinit are the integration with abinit,
>to fit parameters, and the simultaneous dynamics with other
>degrees of freedom (in particular using the inter-atomic force constants).

A tutorial for the multibinit spin model has been written, [[tutorial:spin_model]].

Many new input variables are present, tested and documented:
[[slc_coupling@multibinit|slc_coupling]],
[[spin_calc_thermo_obs@multibinit|spin_calc_thermo_obs]],
[[spin_damping@multibinit|spin_damping]],
[[spin_init_orientation@multibinit|spin_init_orientation]],
[[spin_init_qpoint@multibinit|spin_init_qpoint]],
[[spin_init_rotate_axis@multibinit|spin_init_rotate_axis]],
[[spin_init_state@multibinit|spin_init_state]],
[[spin_ntime_pre@multibinit|spin_ntime_pre]],
[[spin_projection_qpoint@multibinit|spin_projection_qpoint]],
[[spin_sia_add@multibinit|spin_sia_add]],
[[spin_sia_k1amp@multibinit|spin_sia_k1amp]],
[[spin_sia_k1dir@multibinit|spin_sia_k1dir]],
[[spin_temperature_start@multibinit|spin_temperature_start]],
[[spin_temperature_end@multibinit|spin_temperature_end]],
[[spin_temperature_nstep@multibinit|spin_temperature_nstep]],
[[spin_var_temperature@multibinit|spin_var_temperature]],
[[spin_write_traj@multibinit|spin_write_traj]].

List of tests in addition to those of the tutorial: [[test:v8_16]], [[test:v8_23]], [[test:v9_81]], [[test:v9_82]],
[[test:v9_86]], [[test:v9_87]].

By Xu He, N. Helbig, J. Bieder, E. Bousquet, Ph. Ghosez, M. Verstraete

<a name="v9.2.B.5"></a>
**B.5** Constrained DFT

Constrained Density-Functional Theory (see [[topic:ConstrainedDFT]]) is available,
with a new algorithm allowing to impose the constraints to arbitrary precision,
whether it relates to the charge, magnetization, magnetization direction, or magnetisation size,
or a combination thereof for different atoms. The constraints are smeared spherical integrals
with ajustable sphere radius, centered on atoms. The algorithms has been demonstrated for norm-conserving pseudopotentials
as well as PAW. Forces and derivatives with respect to the constraints
are available (i.e. magnetic torque for the non-collinear spin case).
Stresses are still to be coded, will be available in ABINITv9.4 or ABINITv9.6.

New tests: v8#24-29, v8#95-97 and v9#1-3.
New input variables: [[chrgat]], [[constraint_kind]], [[ratsm]].

By X. Gonze.

<a name="v9.2.B.6"></a>
**B.6** Large modifications of the build system

The build system relies on new <hostname>.ac9 files, superceeding the v8 <hostname>.ac files.
Fully documented example files can be found in doc/build/config-examples.
A bash script (`upgrade-build-config-file.sh`) located in the top level directory of the package can be used
   to convert from the old `.ac`format to `.ac9`.

The build system of ABINITv9 does not build anymore the (hard and soft) dependencies (Linalg, NetCDF4, HDF, LibXC, Wannier90, ...), as this was not sustainable.
Three libraries are now mandatory: linalg, NetCDF4/HDF5 and LibXC. Failing to link to them will prevent building ABINIT.
The other libraries are optional, there will only be a warning if they are not available.
If the user does not provide the path to these libraries,
the build system will try to find them in the "usual" directories, and inform the user that it has done so.
The build system also can make suggestions to the user, to complete its *.ac9 file.

Specialized INSTALL notes are available to help the user for
[CentOS](/INSTALL_CentOS), [EasyBuild](/INSTALL_EasyBuild), [MacOS](/INSTALL_MacOS), and [Ubuntu](/INSTALL_Ubuntu).

By Y. Pouillon and JM Beuken

**B.7** New command line interface

There is a new (**recommended**) command line interface to run ABINIT, without the "files" file.
The new syntax is:

    abinit run.abi

or

    abinit run.abi > run.log 2> run.err &

where `run.abi` is the Abinit input file that now provides all the information related to pseudos
and the prefixes that were previously passed via the "files" file. For comparison, the old syntax is

    abinit < run.files > run.log 2> run.err &      ! This is the old syntax

A file extension for the input file is highly recommended (in this example we use `.abi`)
as by default the parser will use the string before the file extension as root to build the prefixes
for the input/output/temporary files.

The user can specify the name of the main output file thanks to the [[output_file]] input variable,
the list of pseudopotentials thanks to the [[pseudos]] input variable and the directory where
all pseudos are located with [[pp_dirpath]].
The prefix for other input, output or temporary files can be specified with [[indata_prefix]], [[outdata_prefix]] and
[[tmpdata_prefix]], respectively.
A default set of prefixes computed from the basename of the input file is used if
these variables are not specified in the input.

For some examples, see tests [[test:v8_90]], [[test:v7_45]], and [[test:v5_54]]. See also [[topic:Control]].

A similar command line interface can also be used for the anaddb code.
In this case, the relevant variables are:
[[output_file@anaddb]], [[ddb_filepath@anaddb]], [[ddk_filepath@anaddb]], [[gkk_filepath@anaddb]], [[eph_prefix@anaddb]].

The new syntax is:

    anaddb run.in > run.log 2> run.err &

See tests [[test:v8_52]] for a standard analysis of the DDB file and
[[test:v7_94]] for the (old implementation) of electron-phonon calculations in anaddb.

!!! important

    The old "files file" interface is still operational although deprecated and will be **REMOVED** in Abinit v10.


By M. Giantomassi (MR 586).


**B.8** Reading strings from the input file

A new mechanism to read strings enclosed between **double quotation marks** from the input file has been activated.
So, many new input keywords are reading strings as data, and, often, can be used alternatively to similar input keywords
that were expecting numerical values such as the `get*` and `ird*` variables.
The goal is to encourage a new approach for performing ABINIT calculations in which multiple datasets
and `get*` variables are replaced by independent input files that are connected together via file paths.

List of new input variables that rely on this feature:

- [[getddb_filepath]], an alternative to [[getddb]] or [[irdddb]], see test [[test:v9_60]]
- [[getden_filepath]], an alternative to [[getden]] or [[irdden]], see test [[test:v8_36]] and [[test:v8_41]]
- [[getscr_filepath]], an alternative to [[getscr]] or [[irdscr]], see test [[test:v67mbpt_51]]
- [[getwfkfine_filepath]], an alternative to [[getwfkfine]] or [[irdwfkfine]], see tests [[test:v9_55]], [[test:v9_56]]
- [[getwfk_filepath]], an alternative to [[getwfk]] or [[irdwfk]], see test [[test:v9_60]]
- [[getwfq_filepath]], an alternative to [[getwfq]] or [[irdwfq]], see test [[test:v7_98]]
- [[getkerange_filepath]], see test [[test:v9_60]]
- [[getpot_filepath]], see test [[test:v8_44]]
- [[pseudos]], [[indata_prefix]], [[outdata_prefix]], [[tmpdata_prefix]], [[output_file]], see test [[test:v9_04]]
- [[pp_dirpath]]: Used in all the input files of the Test Suite
- [[output_file@anaddb]], [[ddb_filepath@anaddb]], [[gkk_filepath@anaddb]], [[eph_prefix@anaddb]].
  See tests [[test:v8_52]] for a standard analysis of the DDB file and
  [[test:v7_94]] for the (old implementation) of electron-phonon calculations in anaddb.

By M. Giantomassi

<a name="v9.2.B.9"></a>
**B.9** YAML sections in the output file

YAML sections are now generated in the output file, sometimes replacing text sections, sometime providing new information.
At present there is a YAML section for the components of the total energy, the GS results including forces and stresses as well as a YAML section for GW calculations, and some YAML sections giving information about the iteration status.
<!--
Example of tests: paral#86, v67mbpt#2. See the input variable use_yaml (TO BE DOCUMENTED).
-->
At the occasion of the development of this capability, and its adaptation to the test farm, the
perl script fldiff.pl has been replaced by a Python version.
See related information in Sec. 5.5 of [[cite:Gonze2020]].

By T. Cavignac, M. Giantomassi, GM Rignanese, X Gonze.


**B.10** New approach to define crystalline structures in the Abinit input

The new variable [[structure]] can be used to initialize the lattice vectors
and the atomic positions **from an external file**.
Variables such as [[natom]], [[ntypat]], [[typat]] and [[znucl]] are automatically initialized
and need not to be specified in the ABINIT input.
At present, the code can read netcdf files produced by ABINIT (`GSR.nc`, `WFK.nc`, `DEN.nc`, `HIST.nc`)
and POSCAR files in VASP-5 format.
See the documentation for the syntax and limitations.

By M. Giantomassi.


**B.11** New capabilities of abipy and abiflows

The abipy and abiflows projects have been significantly extended.
See Sec. 6 of [[cite:Gonze2020]], as well as the [gallery of plotting scripts](http://abinit.github.io/abipy/gallery/index.html) &nbsp;
and the [gallery of abipy workflows](http://abinit.github.io/abipy/flow_gallery/index.html) &nbsp;.

By M. Giantomassi, G. Petretto, F. Naccarato.


* * *

### **C.** Changes for the developers (including information about compilers)

**C.1** A python script to help ABINIT developers and development.

The new python script abisrc.py located in the top directory of the ABINIT package has been developed.
It has superceded abilint.py in the makemake procedure.

Try

    ./abisrc.py --help

then follow the suggestions, to get info about files, directories, interfaces, to visualize
dependencies of the ABINIT subroutines, etc.

Note that there are dependencies of abisrc.py, to be installed prior being able to use some of its capabilities.
Use:

    pip install -r requirements.txt --user

to install the dependencies in user mode.

By M. Giantomassi.

**C.2** New characteristics of input variables

In the description of input variables (e.g. files abimkdocs/variables_abinit.py), a new field `added_in_version` has been introduced,
for example,

     added_in_version="9.2.0"

or, for variables introduced prior to v9,

     added_in_version="before_v9"

**C.2** Test farm: new and obsolete bots

* Bots introduced in the test farm: alps_nag_7.0_openmpi, atlas_gnu_9.1_openmpi, buda2_gnu_8.2_cuda, cronos2_gnu_7.4_paral,
    scope_gnu_10.2_mpich, scope_gnu_7.5_dep.
* Bots upgraded: abiref_gnu_5.3_* to abiref_gnu_9.2_*; bob_gnu_5.3_openmp to bob_gnu_7.5_openmp; buda2_gnu_8.1_mpich3
    to buda2_gnu_8.2_mpich3; graphene_gnu_6.4_macports to graphene_gnu_9.2_macports; max2_gnu_5.3_* to max2_gnu_6.5_*; ubu_gnu_5.3_openmpi to ubu_gnu_9.2_openmpi.
* Bots removed: abiref_nag_6.2_openmpi (superceded by alps_nag_7.0_openmpi), atlas_gnu_7.2_fb.ac (no nightly test of the fallbacks anymore), cronos_gnu_5.3_paral(replaced by cronos2), inca_gnu_6.3_py3k (inca too old), tikal_gnu_* (tikal too old).
Working also on a cronos-cronos2 cluster.

By JM Beuken

**C.3** Supported compilers

* gfort (GNU) compiler: v9 newly supported, v4 obsolete
* ifort (INTEL) compiler: v19 newly supported.
* NAG 7.0 instead of 6.2

By JM Beuken

**C.4** Unitary ttransposer#1 . Test of the transposer for linear algebra to KGB parallelisation.

By J. Bieder.

**C.5** Linkchecker has been reenabled, only for internal link checking.

By JM Beuken (MR 513).

**C.6** Enable the generation of a HTML side-by-side diff on the test farm when fldiff fails with a line count error and it was not caused by a crash of Abinit. The diff algorithms uses a specialized heuristic to improve line synchronization and prevent weird matching.

By Th. Cavignac (MR 526)

**C.7** Split of the source tree (ongoing).

In order to improve modularity, the source tree must be split in two parts, one for low-level routines, largely independent of ABINIT,
and one for more specific routines to ABINIT. The low-level routines should become a separate library, with its own build system and make.
At present the low-level library have been moved out of src, inside the shared/common/src directory.
See related information in Sec. 5.4 of [[cite:Gonze2020]].

**C.8** New FFT specifications for the build system
See https://gitlab.abinit.org/pouillon/abinit/-/issues/33 .

By Y. Pouillon (MR 619)

**C.9** Reorganisation of the tests/Psps_for_tests directory, in preparation of the beautification.
Clarification on which pseudopotentials are of recent format, and which are legacy pseudopotentials.
Preparation of beautification.

By X. Gonze (MR 683)

* * *

<a name="v9.2.D.1"></a>
### **D.**  Other changes (or on-going developments, not yet finalized)

**D.1**  Miscellaneous improvements of Multibinit (lattice part)

Miscellaneous improvements have been made to the lattice part of Multibinit.
See the new input variables below, also see the Sec. 4.1.1 of [[cite:Gonze2020]].

New tests: [[test:v8_38]], [[test:v8_94]], [[test:v8_98]], [[test:v8_99]],
[[test:v8_101]],
[[test:v8_102]],
[[test:v8_103]],
[[test:v9_83]],  [[test:v9_84]], [[test:v9_85]].
New input variables are listed below.
Not all these new input variables are present in automatic tests, though.

- [[analyze_anh_pot@multibinit|analyze_anh_pot]]
- [[dyn_chksym@multibinit|dyn_chksym]]
- [[dyn_tolsym@multibinit|dyn_tolsym]]
- [[fit_efs@multibinit|fit_EFS]]
- [[fit_iatom@multibinit|fit_iatom]]
- [[fit_spc_maxs@multibinit|fit_SPC_maxS]]
- [[latt_friction@multibinit|latt_friction]]
- [[latt_taup@multibinit|latt_taup]] NOT TESTED
- [[latt_taut@multibinit|latt_taut]]
- [[opt_coeff@multibinit|opt_coeff]]
- [[opt_effpot@multibinit|opt_effpot]]
- [[opt_ncoeff@multibinit|opt_ncoeff]]
- [[sel_efs@multibinit|sel_EFS]]
- [[strfact@multibinit|strfact]]
- [[test_effpot@multibinit|test_effpot]]
- [[test_prt_ph@multibinit|test_prt_ph]]
- [[ts_option@multibinit|ts_option]] NOT TESTED

Finally, several input variables of the main ABINIT application are also reused for Multibinit, without modification
of meaning, like [[iatfix]], [[natfix]] (and related similar input variables), and also [[tolmxf]].

By M. Schmitt, Xu He, F. Ricci, M. Verstraete, Ph. Ghosez


**D.2** Miscellaneous improvements in the Chern number and orbital magnetization calculations,
including parallelization over k points of the Chern number calculation.

By J. Zwanziger (MR 469, 500, 545, 588)

**D.3** Calculation of Debye-Waller tensor. New test [[test:v8_58]].

By M. Giantomassi

**D.4** Speed-up of susceptibility matrix calculations and GW analytic continuation calculations.
See the new input variable [[gwaclowrank]] and new test [[test:v9_32]].

By F. Bruneval (MR 687).

**D.5** NCPP Wavefunction mixing with Variational Energy
and minor improvements to prepare PAW+Hybrid variational energy.
New test [[test:v7_73]], simple system for testing Hartree-Fock and the SCF algorithms.

By X. Gonze (MR 434, 444, 445).

**D.6** New weight distribution of the Fourier components of the force constants.
Test tolerance in the new integration weights, tests [[test:v8_52]], [[test:v8_53]], [[test:v8_54]].

By H. Miranda and M. Giantomassi

**D.7** Test calculation of velocity matrix elements (DDK) with
 [[optdriver]] 8 and [[wfk_task]] "wfk_ddk”, see [[test:v8_59]]. By the way, the 
 other capabilities linked to [[wfk_task]] ("wfk_fullbz", "wfk_einterp", "wfk_optics_fullbz", "wfk_kpts_erange") seem
 not to have been properly advertised.

By M. Giantomassi

**D.8** Upgraded [[tutorial:paral_bandpw]], new version of auto paral (with threads)

By M. Torrent (MR502).

**D.9** Test wannier90 interface with [[nsppol]]=2 and [[nspden]]=2, [[test:wannier90_04]].

By Xu He

**D.10** Mixed precision for FFT transforms. New input variable [[mixprec]]
see [[test:v8_44]], [[test:v9_57]], [[test:v9_60]], and [[test:v9_61]].

From M. Giantomassi (MR491).

**D.11** Multibinit has been interfaced with [scale-up](https://www.secondprinciples.unican.es).

By Marcus Schmitt, Jordan Bieder, Matthieu Verstraete and Philippe Ghosez

**D.12** The following units are now also allowed in input files:

- S Sec Second  for the ABINIT input file;
- nm (for nanometer)  for the ABINIT and ANADDB input files.

**D.13** aTDEP utility:
added [[pdf:aTDEP_Guide| aTDEP guide]],
[[topic:aTDEP|aTDEP topic]], and corresponding input variable documentation.
References: [[pdf:aTDEP_Paper|aTDEP paper]].
Also, see Sec. 4.2 of [[cite:Gonze2020]].

By F. Bottin, J. Bouchet, J. Bieder (MR491,422).

**D.14** Improvements of NLO calculations.
Optimize memory allocation. In particular for [[usepead]] = 1.
Write Raman susceptibilities to netcdf in anaddb.

By G. Petretto  (MR 599).

**D.15** MetaGGA + PAW in progress.
All internal and unit tests are OK. The implementation seems close to the end. Still need to perform physical tests.

By M. Torrent and J.-B. Charraud (MR 587, 558, 625).

**D.16** Implementation of an alternate version of MPI reductions valid when the number of data exceeds 2^32.

By M. Torrent (MR 587)

**D.17** Build system and src support for llvm (clang/flang) and ARM (armflang/armclang/armpl).

By M Torrent (MR 571)

**D.18** Improvement of core WF reading (optics + electron-positron)

By M Torrent (MR 557)

**D.19** Fix bootstrap kernel convergence issues

By Wei Chen (MR 546)

**D.20** Upgrade versions of libraries used with ABINIT.
Upgrade atompaw to 4.1.0.6. Upgrade Libxc to 4+. Prepare the interface to LibXC 5 and a bit of LibXC 6.

By M. Torrent, JM Beuken (MR 649, 532, 470, 465, 441)

**D.21** Write yaml file for fatbands (phonopy format) with aTDEP

By J. Bieder (MR510)

**D.22** Write polarization vectors in GSR.nc.

By H. Miranda (MR 462).

**D.23** Updated user interface of Raman_spec.py . Added one section to tutorial NLO to describe use of Raman_spec.py.

By N. Pike (MR 460, MR 581)

**D.24** XML format for core wavefunctions

By F. Jollet (MR 423)

**D.25** Wavefunction prediction for molecular dynamics.

By F. Jollet (MR 412)

**D.26** Added a preview for the toptic_4.abi file in the optic tutorial.

By F. Goudreault (MR 408)

**D.27** Improve ELPA detection; make abinit compatible with ELPA2019

By M. Torrent (MR 626)

**D.28** Upgrade of [[tutorial:base3]] and [[tutorial:basepar]].

By X. Gonze (MR628)

**D.29** New input variable [[prtprocar]], see test [[test:v9_108]].

By M. Verstraete (MR630)

**D.30** The ABINIT input variable [[supercell_latt]] is documented.
See also [[test:v8_94]].

By X. Gonze

**D.31** New implementation of the cRPA (to compute U and J in DFT+U or DFT+DMFT)
that can consider any subset of orbitals in the system.
Compilation was a bit long on certain compilers, so new keywords have been added to the build system:
enable_crpa_optim and enable_crpa_no_optim

By R. Outerov and B. Amadon (MR622).

<a name="v9.2.D.32"></a>
**D.32** On-going work on refactoring the Coulomb interaction part of ABINIT.

New input variables [[fock_icutcoul]], and [[gw_icutcoul]], that should superceed [[icutcoul]].
New test added for the mini-Brillouin Zone integration, [[gw_icutcoul]]=14, 15, 16, see [[test:v9_21]].

By B. Guster, M. Giantomassi, F. Bruneval and X. Gonze (MR 627, 633, 673, 679, 686).

**D.33** New TB2J python script to compute the superexchange (J) and the Dzyaloshinskii-Moriya (DMI) interactions. The script can be found in [http://gitlab.abinit.org/xuhe/TB2J](http://gitlab.abinit.org/xuhe/TB2J) with doc and tutorials. The script is interfaced with wannier90 and use the w90 output files. The J calculation works in production, the DMI is much more sensitive to disentanglement noise and have to be use with care. An article is under construction to describe the method and its implementation. The script can deliver input data file for the spin model of Multibinit.

By He Xu, M. Verstraete and E. Bousquet (MR 639).

**D.34** Test linear electro-optical coefficient, tutorespfn [[test:optic_5]].

By N. Pike (MR 575).


**D.35** Optic: print spin-decomposition when applicable.
Fixed reflectivity screwed results. Test more thoroughly optics (incl. interfacing using NetCDF),
see new tests [[test:v9_05]] to [[test:v9_12]], also [[test:v9_47]] and [[test:v9_48]]

By X. Gonze (MR 654, 674).

**D.36** Fixed DFPT+PAW+GGA+usexcnhat=1+q<> bug, and also add new related tests
[[test:v9_41]] and [[test:v9_42]].

By M. Torrent and X. Gonze (MR 657).

**D.37** Update PAW tutorial

By F. Jollet (MR 643, 645, 652, 653).

**D.38** Nonlinear xc preliminary

Preliminary work for some changes in the exchange correlation terms in nonlinear (3rd order DFPT).
One term was implemented in both pead and dfptnl routines. Now it is merged in one routine (dfptnl_exc3).
Due to a subtle reordering of nonlinear core correction terms, some pead refs are changed, but the final result ("First order change in electronic dielectric susceptibility tensor") remain the same.

By L. Baguet (MR 650).

**D.39** Anaddb output data prefix

The former writing of anaddb.nc (fixed path and fixed name) has been made more flexible, by
introducing a prefix

By J. Bieder and He Xu (MR702)

**D.40** New "macro" input variable [[expert_user]]

When non-zero [[expert_user]] automatically switch off all checks done by [[chkprim]], [[chkdilatmx]], [[chksymbreak]] and [[chksymtnons]].

By X. Gonze (MR715)


**D.41** Miscellaneous additional bug fixes, improvements of documentation including for the build system.
G. Antonius, L. Baguet, JM Beuken, J. Bieder, E. Bousquet, F. Bruneval, T. Cavignac, M. Giantomassi, X. Gonze,
F. Jollet, R. Outerovitch, N. Pike, Y Pouillon, M. Royo, M. Torrent, J. Van Bever, M. Verstraete, Xu He.

* * *

## v9.0

Version 9.0, released on March 29, 2020.
List of changes with respect to version 8.10.

Many thanks to the contributors to the ABINIT project between
October 2018 and March 2020. These release notes
are relative to modifications/improvements of ABINIT v9.0 with respect to v8.10
(merge requests up to, and including, MR636 are taken into account)

The list of contributors includes:
B. Amadon, L. Baguet, J.-M. Beuken, J. Bieder, J. Bouchet, E. Bousquet, F. Bruneval, G. Brunin, Wei Chen,
J.-B. Charraud, Ph. Ghosez, M. Giantomassi, O. Gingras, X. Gonze, F. Goudreault,
B. Guster, G. Hautier, Xu He, N. Helbig, F. Jollet,
H. Miranda, F. Naccarato, R. Outerov, G. Petretto, N. Pike, Y. Pouillon, F. Ricci, M. Royo,
M. Schmitt, M. Stengel, M. Torrent, J. Van Bever, M. Verstraete, J. Zwanziger.

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

### **A.** Important remarks and warnings.

**A.1** At the occasion of the switch from ABINITv8 to ABINITv9, many improvements of the formats and content of files written
    by ABINIT have been made, so the backward compatibility of ABINITv9 may be broken.
    The present ABINITv9.0 is NOT to be considered a production version. It is a beta release, allowing developers to get feedback
    from the users. Many features will work correctly, of course. Still, beginners are advised
    to stick to ABINITv8.10.3 except if ABINITv8.10.3 is not appropriate (or not working) for them.

In particular:

1. The build system relies on new `.ac9` files (see [B.6](#v9.0.B.6)), superceeding the v8 `.ac` files.
   A bash script (`upgrade-build-config-file.sh`) located in the top level directory of the package can be used
   to convert from the old `.ac`format to `.ac9`.
2. The build system of ABINITv9 does not build anymore the hard dependencies (Linalg, NetCDF4, HDF5, LibXC, ...),
as this was not sustainable (see [B.6](#v9.0.B.6)) and nowadays most users install prerequisite libraries themselves.
3. The main ABINIT output file now contains sections written in YAML (sometimes replacing text sections, sometimes adding information).
    This means that some user-developed parsing tools might not work anymore, and should be adapted to the new ABINITv9 output file (see [B.9](#v9.0.B.9)). Note that the YAML output is still under development and modifications may appear in the next versions. A python API to extract the results of the calculation will be provided when the implementation is finalized.
4. Several default values have been changed, see [A.3](#v9.0.A.3).


**A.2**
A new account of the ABINIT effort has been published in Computer Phys. Comm. [[cite:Gonze2020]]
It provides description of several new features.
A version of this paper that is not formatted for Computer Phys. Comm.
[is also available](https://www.abinit.org/sites/default/files/ABINIT20.pdf).
The licence allows the authors to put it on the Web.

A second new account of the ABINIT effort has been published in J. Chem. Phys. [[cite:Romero2020]].
The scope of this second paper is different from the first one. It is more a survey of ABINIT,
focusing on its specific capabilities. Still, it contains also some description of some new features.
A version of this paper that is not formatted for J. Chem. Phys.
[is also available](https://www.abinit.org/sites/default/files/ABINIT20_JPC.pdf).
The licence allows the authors to put it on the Web.

Other specific publications are mentioned in the [Suggested acknowledgment page](/theory/acknowledgments).

<a name="v9.0.A.3"></a>
**A.3**  The default values of the following ABINIT input variables have been changed:
    [[ixcrot]], [[chneut]], [[ntime]], [[symsigma]], [[prtkden]].

**A.4** The initialization of the wavefunctions when [[paral_kgb]]=1 and [[nspinor]]=2 has been changed, since the previous one could prevent the code to converge.
    By M Torrent (MR 562).

**A.5** The input variable xangst has been disabled. Use xcart instead, and specify the unit, namely Angstrom.

**A.6** The name of the t-DEP main executable has been changed from `tdep" to `atdep`, in line with [[cite:Romero2020]].

* * *

### **B.** Most noticeable achievements

**B.1** Electron-phonon interaction (mobilities in the self-energy relaxation time approximation,
temperature-dependent electronic band structures including the zero-point renormalization, etc.)

The new capabilities of ABINITv9 related to electron-phonon calculations are described
fully in the Sec. 3.3.2 of [[cite:Gonze2020]], as follows.

>   In abinit v9, it is possible to compute the EPH self-energy
>   in the Kohn–Sham representation using the EPH matrix
>   elements. The code employs optimized algorithms to compute
>   either the full self-energy (needed for QP corrections and spectral
>   functions) or just the imaginary part that is then used to evaluate
>   mobilities within the self-energy relaxation time approximation
>   (SERTA). The computation of the mobility is fully
>   integrated inside abinit, and is an automatic output of the
>   computation of the imaginary part of the self-energy, bypassing
>   the need to post-process results. When computing the full self-energy,
>   it is possible to reduce the number of empty states
>   required for convergence by using the first-order wavefunctions
>   obtained by solving the relevant Sternheimer equation.
>
>   In the case of lifetime computations, the code takes advantage of the
>   tetrahedron method to filter contributing q-points, a double-grid
>   integration technique to accelerate the convergence at marginal
>   additional computational cost, and samples the relevant regions
>   in the Brillouin zone contributing to transport properties thus
>   leading to a significant reduction of the computational effort.
>   Crystalline symmetries are used throughout the code in order to
>   reduce the number of k- and q-points that must be explicitly
>   included in the integrals. To achieve good parallel efficiently, the
>   most CPU demanding parts are parallelized with MPI employing a
>   distribution schemes over k/q-points, perturbations and bands (the
>   band level is available only when computing the full self-energy).

Moreover, the interpolation of the DFPT potential, described in Sec. 3.3.1 of [[cite:Gonze2020]] is fully operational,
with many tests provided.

List of tests: [[test:v9_50]], [[test:v9_61]] and [[test:v8_44]].

New input variables: [[dvdb_qcache_mb]],
[[eph_phrange]], [[eph_tols_idelta]], [[eph_ecutosc]], [[eph_restart]],
[[eph_stern]], [[eph_use_ftinterp]],
[[getdvdb]], [[getdvdb_filepath]], [[getkerange_filepath]],
[[irddvdb]], [[prteliash]], [[sigma_bsum_range]], [[sigma_erange]],
[[sigma_ngkpt]], [[sigma_nshiftk]], [[sigma_shiftk]], [[symv1scf]].

Note that the new EPH processing unit of ABINIT [[optdriver]]=7 has a different implementation than the one implemented in anaddb.
A new set of tutorials are in preparation and they will be made available in the forthcoming versions.
For further details about the implementation, please consult this [preprint](https://arxiv.org/abs/2002.00630).

By G. Brunin, H. Miranda, M. Giantomassi, G.-M. Rignanese, G. Hautier.

**B.2** Flexoelectricity and dynamical quadrupoles

A new driver has been included in abinit that allows one to compute
4 spatial dispersion tensorial quantities: the clamped-ion flexoelectric tensor, the dynamical quadrupoles,
the first moment of IFC matrix and the first moment of the piezoelectric force response tensor.
Precalculation of ground state, first and second (d2_dkdk) order response functions is required.
After execution, the driver creates a 3rd order energy derivative database file
that is used by anaddb to compute the mixed and lattice-mediated flexoelectric tensors
or to include the dipole-quadrupole and quadrupole-quadrupole electrostatic interactions
in the calculation of the dynamical matrix.

See the complementary description
in the Sec. V. D of [[cite:Romero2020]], with underlying theory and test calculations
presented in [[cite:Royo2019]].

At the practical level, see [[cite:Romero2020]]:

>   In this way, both perturbations are generalized to finite q, as
>   is already the case for atomic displacements. This enables us
>   to carry out an analytical third order derivative of the energy
>   with respect to two of the standard perturbations, and to the
>   momentum q, which directly provides the sought-after spatial
>   dispersion tensors. Remarkably, by virtue of the 2n+1 theorem,
>   the third-order energies are computed in one shot using
>   precalculated first-order response functions to the standard
>   perturbations, without the necessity of self-consistently computing
>   any response function to a perturbation gradient. After
>   execution, the long-wave DFPT routines generate a derivative
>   database that is subsequently used by post-processing tools
>   implemented in ANADDB to compute and print the different
>   contributions to the FxE tensor.

>   The dynamical quadrupoles are the spatial dispersion counterparts of the Born effective charges,
>   and can be used in lattice dynamics calculations
>   to improve the prevalent dipole-dipole treatment of the
>   long-range interactions. The ANADDB routines that carry
>   out the process of interpolating the dynamical matrix following
>   Ref. 34 have been adapted to incorporate the dipole-quadrupole
>   and quadrupole-quadrupole electrostatic interactions
>   derived in Ref. 102. This new functionality results in a
>   faster convergence of the phonon bands calculation with respect
>   to the density of q points and, in some materials, represents
>   the only route to obtain the correct sound velocities.

>   Currently, the implementation is restricted to the use of
>   norm-conserving pseudopotentials without non-linear core corrections, and the LDA
>   functional.

A tutorial is in preparation, with tests [[test:lw_1]] to [[test:lw_7]],
as well as a specific topic.

New input variables have been defined: [[lw_flexo]], [[lw_qdrpl]], [[prepalw]], [[flexoflag@anaddb]],
[[dipquad@anaddb]], [[quadquad@anaddb]].

This capability is still under development and not completely stable.
Interested users are strongly recommended to contact Miquel Royo (mroyo@icmab.es)
or Massimiliano Stengel (mstengel@icmab.es) before start using it.

By M. Royo, M. Stengel, M. Giantomassi.


**B.3** DFT+DMFT

The new capabilities of ABINITv9 related to DFT+DMFT calculations are described
fully in the Sec. 3.7 of [[cite:Gonze2020]], as follows.

>   The DFT+DMFT parallelism was improved for large
>   systems. In particular, it is now possible to parallelize the calculation
>   on both k-points and bands/g-vectors by using the input
>   variable [[paral_kgb]] = 1 and related input variables.
>
>   Two new approaches to CT-QMC have been added to
>   solve the AIM. In the first one, the density–density CT-QMC code
>   available in abinit [[cite:Gonze2016]], [[cite:Bieder2014]] was generalized in order to take into
>   account off-diagonal elements of the hybridization function. This
>   implementation is activated with the input variable [[dmft_solv]]
>   = 8. Spin–orbit coupling calculations are possible, but using a
>   real valued imaginary time hybridization function. This solver was
>   used in Refs. [[cite:Amadon2015]], [[cite:Amadon2016]].
>
>   In the second approach, we use the Toolbox for Research
>   on Interacting Quantum System (TRIQS)library [[cite:Parcollet2015]], which is an
>   open-source project that provides a framework for many-body
>   quantum physics and more specifically for strongly-correlated
>   electronic systems. TRIQS provides an open source implementation
>   of the continuous-time hybridization expansion quantum
>   impurity solver (CT-HYB) [[cite:Seth2016]], considered a state-of-the art
>   solver for multi-orbital AIM. An interface between abinit and
>   the impurity solver TRIQS/CT-HYB is now available and will make
>   use of the independent progress made by the TRIQS library. <...>

Also, the DMFT k-resolved spectral function is available (MR 529, 490).

List of tests: [[test:paral_84]], [[test:paral_86]], [[test:paral_99]], [[test:v8_01]].
New input variables: [[dmft_charge_prec]] and [[dmft_kspectral_func]] (test to be provided for the latter).
Also [[dmft_occnd_imag]], but only for keeping backward compatibility for tests.

By T. Cavignac, B. Amadon and O. Gingras.


**B.4** Spin model within Multibinit

The new capabilities of Multibinit within ABINITv9 are described
fully in the Sec. 4.1 of [[cite:Gonze2020]]. See also Sec. [D.1](#v9.0.D.1).
In particular, a spin model, described specifically in Sec. 4.1.2 of [[cite:Gonze2020]], is available, as follows.

>Multibinit implements the most commonly used model for spin systems,
>via the Heisenberg Hamiltonian including magnetic exchange and Dzyaloshinskii Moriya interactions.
>Single ion anisotropy and dipole–dipole interactions are also included,
>and all terms bear a very strong similarity to the quadratic part of the lattice model Hamiltonian.
>A number of open source spin dynamics codes already exist, such as UPPASD, VAMPIR, OOMF;
>the distinguishing features of multibinit are the integration with abinit,
>to fit parameters, and the simultaneous dynamics with other
>degrees of freedom (in particular using the inter-atomic force constants).

A tutorial for the multibinit spin model has been written, [[tutorial:spin_model]].

Many new input variables are present.
Not all these new input variables are present in automatic tests, though, in this beta-release.
These "non-tested" input variables are indicated below with 'NT'.
This will be completed for the production version v9.2 .
List of tests in addition to those of the tutorial: [[test:v8_16]], [[test:v8_23]], [[test:v9_81]], and [[test:v9_82]].

New input variables tested and documented:
[[spin_calc_thermo_obs@multibinit|spin_calc_thermo_obs]],
[[spin_damping@multibinit|spin_damping]],
[[spin_init_orientation@multibinit|spin_init_orientation]],
[[spin_init_qpoint@multibinit|spin_init_qpoint]],
[[spin_init_rotate_axis@multibinit|spin_init_rotate_axis]],
[[spin_init_state@multibinit|spin_init_state]],
[[spin_ntime_pre@multibinit|spin_ntime_pre]],
[[spin_projection_qpoint@multibinit|spin_projection_qpoint]],
[[spin_sia_add@multibinit|spin_sia_add]],
[[spin_sia_k1amp@multibinit|spin_sia_k1amp]],
[[spin_sia_k1dir@multibinit|spin_sia_k1dir]],
[[spin_temperature_start@multibinit|spin_temperature_start]],
[[spin_temperature_end@multibinit|spin_temperature_end]],
[[spin_temperature_nstep@multibinit|spin_temperature_nstep]],
[[spin_var_temperature@multibinit|spin_var_temperature]],
[[spin_write_traj@multibinit|spin_write_traj]].
Additionnal new input variables:
[[slc_coupling@multibinit|slc_coupling]] (NT),
spin_calc_correlation_obs (NT and not documented),
spin_calc_traj_obs (NT and not documented),
[[spin_projection_qpoint@multibinit|spin_projection_qpoint]] (NT).

By Xu He, N. Helbig, J. Bieder, E. Bousquet, Ph. Ghosez, M. Verstraete


**B.5** Constrained DFT

Constrained Density-Functional Theory (see [[topic:ConstrainedDFT]]) is available,
with a new algorithm allowing to impose the constraints to arbitrary precision,
whether it relates to the charge, magnetization, magnetization direction, or magnetisation size,
or a combination thereof for different atoms. The constraints are smeared spherical integrals
with ajustable sphere radius, centered on atoms. The algorithms has been demonstrated for norm-conserving pseudopotentials
as well as PAW. Forces and derivatives with respect to the constraints
are available (i.e. magnetic torque for the non-collinear spin case).
Stresses are still to be coded, will be available in ABINITv9.2.

New tests: v8#24-29, v8#95-97 and v9#1-3.
New input variables: [[chrgat]], [[constraint_kind]], [[ratsm]].

By X. Gonze.

<a name="v9.0.B.6"></a>
**B.6** Large modifications of the build system

The build system relies on new <hostname>.ac9 files, superceeding the v8 <hostname>.ac files.
Fully documented example files can be found in doc/build/config-examples.
A bash script (`upgrade-build-config-file.sh`) located in the top level directory of the package can be used
   to convert from the old `.ac`format to `.ac9`.

The build system of ABINITv9 does not build anymore the (hard and soft) dependencies (Linalg, NetCDF4, HDF, LibXC, Wannier90, ...), as this was not sustainable.
Three libraries are now mandatory: linalg, NetCDF4/HDF5 and LibXC. Failing to link to them will prevent building ABINIT.
The other libraries are optional, there will only be a warning if they are not available.
If the user does not provide the path to these libraries,
the build system will try to find them in the "usual" directories, and inform the user that it has done so.
The build system also can make suggestions to the user, to complete its *.ac9 file.

By Y. Pouillon and JM Beuken

**B.7** New command line interface

There is a new (**recommended**) command line interface to run ABINIT, without the "files" file.
The new syntax is:

    abinit run.abi

or

    abinit run.abi > run.log 2> run.err &

where `run.abi` is the Abinit input file that now provides all the information related to pseudos
and the prefixes that were previously passed via the "files" file. For comparison, the old syntax is

    abinit < run.files > run.log 2> run.err &      ! This is the old syntax

A file extension for the input file is highly recommended (in this example we use `.abi`)
as by default the parser will use the string before the file extension as root to build the prefixes
for the input/output/temporary files.

The user can specify the name of the main output file thanks to the [[output_file]] input variable,
the list of pseudopotentials thanks to the [[pseudos]] input variable and the directory where
all pseudos are located with [[pp_dirpath]].
The prefix for other input, output or temporary files can be specified with [[indata_prefix]], [[outdata_prefix]] and
[[tmpdata_prefix]], respectively.
A default set of prefixes computed from the basename of the input file is used if
these variables are not specified in the input.

For some examples, see tests [[test:v8_90]], [[test:v7_45]], and [[test:v5_54]]. See also [[topic:Control]].

A similar command line interface can also be used for the anaddb code.
In this case, the relevant variables are:
[[output_file@anaddb]], [[ddb_filepath@anaddb]], [[ddk_filepath@anaddb]], [[gkk_filepath@anaddb]], [[eph_prefix@anaddb]].

The new syntax is:

    anaddb run.in > run.log 2> run.err &

See tests [[test:v8_52]] for a standard analysis of the DDB file and
[[test:v7_94]] for the (old implementation) of electron-phonon calculations in anaddb.

!!! important

    The old "files file" interface is still operational although deprecated and will be **REMOVED** in Abinit v10.


By M. Giantomassi (MR 586).


**B.8** Reading strings from the input file

A new mechanism to read strings enclosed between **double quotation marks** from the input file has been activated.
So, many new input keywords are reading strings as data, and, often, can be used alternatively to similar input keywords
that were expecting numerical values such as the `get*` and `ird*` variables.
The goal is to encourange a new approach for performing ABINIT calculations in which multiple datasets
and `get*` variables are replaced by indipendent input files that are connected together via file paths.

List of new input variables that rely on this feature:

- [[getddb_filepath]], an alternative to [[getddb]] or [[irdddb]], see test [[test:v9_60]]
- [[getden_filepath]], an alternative to [[getden]] or [[irdden]], see test [[test:v8_36]] and [[test:v8_41]]
- [[getscr_filepath]], an alternative to [[getscr]] or [[irdscr]], see test [[test:v67mbpt_51]]
- [[getwfkfine_filepath]], an alternative to [[getwfkfine]] or [[irdwfkfine]], see tests [[test:v9_55]], [[test:v9_56]]
- [[getwfk_filepath]], an alternative to [[getwfk]] or [[irdwfk]], see test [[test:v9_60]]
- [[getwfq_filepath]], an alternative to [[getwfq]] or [[irdwfq]], see test [[test:v7_98]]
- [[getkerange_filepath]], see test [[test:v9_60]]
- [[getpot_filepath]], see test [[test:v8_44]]
- [[pseudos]], [[indata_prefix]], [[outdata_prefix]], [[tmpdata_prefix]], [[output_file]], see test [[test:v9_04]]
- [[pp_dirpath]]: cannot be tested  EXPLICITLY because system dependent but used by runtests.py when generating the input file.
- [[output_file@anaddb]], [[ddb_filepath@anaddb]], [[gkk_filepath@anaddb]], [[eph_prefix@anaddb]].
  See tests [[test:v8_52]] for a standard analysis of the DDB file and
  [[test:v7_94]] for the (old implementation) of electron-phonon calculations in anaddb.

By M. Giantomassi

<a name="v9.0.B.9"></a>
**B.9** YAML sections in the output file

YAML sections are now generated in the output file, sometimes replacing text sections, sometime providing new information.
At present there is a YAML section for the components of the total energy, the GS results including forces and stresses as well as a YAML section for GW calculations, and some YAML sections giving information about the iteration status.
<!--
Example of tests: paral#86, v67mbpt#2. See the input variable use_yaml (TO BE DOCUMENTED).
-->
At the occasion of the development of this capability, and its adaptation to the test farm, the
perl script fldiff.pl has been replaced by a Python version.
See related information in Sec. 5.5 of [[cite:Gonze2020]].

By T. Cavignac, M. Giantomassi, GM Rignanese, X Gonze.


**B.10** New approach to define crystalline structures in the Abinit input

The new variable [[structure]] can be used to initialize the lattice vectors
and the atomic positions **from an external file**.
Variables such as [[natom]], [[ntypat]], [[typat]] and [[znucl]] are automatically initialized
and need not to be specified in the ABINIT input.
At present, the code can read netcdf files produced by ABINIT (`GSR.nc`, `WFK.nc`, `DEN.nc`, `HIST.nc`)
and POSCAR files in VASP-5 format.
See the documentation for the syntax and limitations.

By M. Giantomassi.


**B.11** New capabilities of abipy and abiflows

The abipy and abiflows projects have been significantly extended.
See Sec. 6 of [[cite:Gonze2020]], as well as the [gallery of plotting scripts](http://abinit.github.io/abipy/gallery/index.html) &nbsp;
and the [gallery of abipy workflows](http://abinit.github.io/abipy/flow_gallery/index.html) &nbsp;.

By M. Giantomassi, G. Petretto, F. Naccarato.


* * *

### **C.** Changes for the developers (including information about compilers)

**C.1** A python script to help ABINIT developers and development.

The new python script abisrc.py located in the top directory of the ABINIT package has been developed.
It has superceded abilint.py in the makemake procedure.

Try

    ./abisrc.py --help

then follow the suggestions, to get info about files, directories, interfaces, to visualize
dependencies of the ABINIT subroutines, etc.

Note that there are dependencies of abisrc.py, to be installed prior being able to use some of its capabilities.
Use:

    pip install -r requirements.txt --user

to install the dependencies in user mode.

By M. Giantomassi.

**C.2** New characteristics of input variables

In the description of input variables (e.g. files abimkdocs/variables_abinit.py), a new field `added_in_version` has been introduced,
for example,

     added_in_version="9.0.0"

or, for variables introduced prior to v9,

     added_in_version="before_v9"

**C.2** Test farm: new and obsolete bots

* Bots introduced in the test farm: atlas_gnu_9.1_openmpi, buda2_gnu_8.2_cuda, cronos2_gnu_7.4_paral.
* Bots upgraded: abiref_gnu_5.3_* to abiref_gnu_9.2_* ; abiref_nag_6.2_openmpi to
    abiref_nag_7.0_openmpi; bob_gnu_5.3_openmp to bob_gnu_7.5_openmp; buda2_gnu_8.1_mpich3
    to buda2_gnu_8.2_mpich3; graphene_gnu_6.4_macports to graphene_gnu_9.2_macports; max2_gnu_5.3_* to max2_gnu_6.5_*; ubu_gnu_5.3_openmpi to ubu_gnu_9.2_openmpi.
* Bots removed: atlas_gnu_7.2_fb.ac (no nightly test of the fallbacks anymore), cronos_gnu_5.3_paral(remplaced by cronos2), inca_gnu_6.3_py3k (inca too old), tikal_gnu_* (tikal too old).
Working also on a cronos-cronos2 cluster.

By JM Beuken

**C.3** Supported compilers

* gfort (GNU) compiler: v9 newly supported, v4 obsolete
* ifort (INTEL) compiler: v19 newly supported.
* NAG 7.0 instead of 6.2

By JM Beuken

**C.4** Unitary ttransposer#1 . Test of the transposer for linear algebra to KGB parallelisation.

By J. Bieder.

**C.5** Linkchecker has been reenabled, only for internal link checking.

By JM Beuken (MR 513).

**C.6** Enable the generation of a HTML side-by-side diff on the test farm when fldiff fails with a line count error and it was not caused by a crash of Abinit. The diff algorithms uses a specialized heuristic to improve line synchronization and prevent weird matching.

By Th. Cavignac (MR 526)

**C.7** Split of the source tree (ongoing).

In order to improve modularity, the source tree must be split in two parts, one for low-level routines, largely independent of ABINIT,
and one for more specific routines to ABINIT. The low-level routines should become a separate library, with its own build system and make.
At present the low-level library have been moved out of src, inside the shared/common/src directory.
See related information in Sec. 5.4 of [[cite:Gonze2020]].

**C.8** New FFT specifications for the build system
See https://gitlab.abinit.org/pouillon/abinit/-/issues/33 .

By Y. Pouillon (MR 619)

* * *

<a name="v9.0.D.1"></a>
### **D.**  Other changes (or on-going developments, not yet finalized)

**D.1**  Miscellaneous improvements of Multibinit (lattice part)

Miscellaneous improvements have been made to the lattice part of Multibinit.
See the new input variables below, also see the Sec. 4.1.1 of [[cite:Gonze2020]].

New tests: [[test:v8_38]], [[test:v8_94]], [[test:v8_98]], [[test:v8_99]], [[test:v9_83]],  [[test:v9_84]], and [[test:v9_85]].
New input variables are listed below.
Not all these new input variables are present in automatic tests, though, in this beta-release.
These "non-tested" input variables are indicated below with 'NT'.
Also, not all of these are documented, or only partly documented (e.g. variable type, acronym, default, but no more).
This will be completed for the production version v9.2 .

- [[analyze_anh_pot@multibinit|analyze_anh_pot]]
- fit_SPC_maxS@multibinit (NT)
- fit_iatom@multibinit [[test:paral_81]], [[test:paral_82]], [[test:v8_13]], [[test:v8_14]], but not documented.
- latt_compressibility@multibinit, NOT TESTED, NOT DOCUMENTED
- [[latt_friction@multibinit|latt_friction]]
- latt_mask@multibinit, NOT TESTED, NOT DOCUMENTED
- [[latt_taup@multibinit|latt_taup]] Despite the link, NOT TESTED, only partly DOCUMENTED
- [[latt_taut@multibinit|latt_taut]] Despite the link only partly DOCUMENTED
- [[opt_coeff@multibinit|opt_coeff]]
- [[opt_effpot@multibinit|opt_effpot]]
- [[opt_ncoeff@multibinit|opt_ncoeff]]
- prt_names, NOT TESTED, NOT DOCUMENTED
- [[test_effpot@multibinit|test_effpot]] v8#98

By M. Schmitt, Xu He, F. Ricci, M. Verstraete, Ph. Ghosez


**D.2** Miscellaneous improvements in the Chern number and orbital magnetization calculations,
including parallelization over k points of the Chern number calculation.

By J. Zwanziger (MR 469, 500, 545, 588)

**D.3** Calculation of Debye-Waller tensor. New test [[test:v8_58]].

By M. Giantomassi


**D.4** Test linear electro-optical coefficient, tutorespfn [[test:optic_5]].

By N. Pike (MR 575).

**D.5** NCPP Wavefunction mixing with Variational Energy
and minor improvements to prepare PAW+Hybrid variational energy.
New test [[test:v7_73]], simple system for testing Hartree-Fock and the SCF algorithms.

By X. Gonze (MR 434, 444, 445).

**D.6** New weight distribution of the Fourier components of the force constants.
Test tolerance in the new integration weights, tests [[test:v8_52]], [[test:v8_53]], [[test:v8_54]].

By H. Miranda and M. Giantomassi

**D.7** Test calculation of velocity matrix elements (DDK) with
 optdriver 8 and [[wfk_task]] "wfk_ddk”, see [[test:v8_59]].

By M. Giantomassi

**D.8** Upgraded [[tutorial:paral_bandpw]], new version of auto paral (with threads)

By M. Torrent (MR502).

**D.9** Test wannier90 interface with [[nsppol]]=2 and [[nspden]]=2, [[test:wannier90_04]].

By Xu He

**D.10** Mixed precision for FFT transforms. New input variable [[mixprec]]
see [[test:v8_44]], [[test:v9_57]], [[test:v9_60]], and [[test:v9_61]].

From M. Giantomassi (MR491).

**D.11** Multibinit has been interfaced with scale-up,
[[https://www.secondprinciples.unican.es]]

By Marcus Schmitt, Jordan Bieder, Matthieu Verstraete and Philippe Ghosez

**D.12** The following units are now also allowed in input files:

- S Sec Second  for the ABINIT input file;
- nm (for nanometer)  for the ABINIT and ANADDB input files.

**D.13** aTDEP utility:
added [[pdf:aTDEP_Guide| aTDEP guide]],
[[topic:aTDEP|aTDEP topic]], and corresponding input variable documentation.
References: [[pdf:aTDEP_Paper|aTDEP paper]].
Also, see Sec. 4.2 of [[cite:Gonze2020]].

By F. Bottin, J. Bouchet, J. Bieder (MR491,422).

**D.14** Improvements of NLO calculations.
Optimize memory allocation. In particular for [[usepead]] = 1.
Write Raman susceptibilities to netcdf in anaddb.

By G. Petretto  (MR 599).

**D.15** MetaGGA + PAW in progress.
All internal and unit tests are OK. The implementation seems close to the end. Still need to perform physical tests.

By M. Torrent and J.-B. Charraud (MR 587, 558, 625).

**D.16** Implementation of an alternate version of MPI reductions valid when the number of data exceeds 2^32.

By M. Torrent (MR 587)

**D.17** Build system and src support for llvm (clang/flang) and ARM (armflang/armclang/armpl).

By M Torrent (MR 571)

**D.18** Improvement of core WF reading (optics + electron-positron)

By M Torrent (MR 557)

**D.19** Fix bootstrap kernel convergence issues

By Wei Chen (MR 546)

**D.20** Upgrade versions of libraries used with ABINIT.
Upgrade atompaw to 4.1.0.6. Upgrade Libxc to 4+.

By M. Torrent, JM Beuken (MR 532, 470, 465, 441)

**D.21** Write yaml file for fatbands (phonopy format) with aTDEP

By J. Bieder (MR510)

**D.22** Write polarization vectors in GSR.nc.

By H. Miranda (MR 462).

**D.23** Updated user interface of Raman_spec.py . Added one section to tutorial NLO to describe use of Raman_spec.py.

By N. Pike (MR 460, MR 581)

**D.24** XML format for core wavefunctions

By F. Jollet (MR 423)

**D.25** Wavefunction prediction for molecular dynamics.

By F. Jollet (MR 412)

**D.26** Added a preview for the toptic_4.abi file in the optic tutorial.

By F. Goudreault (MR 408)

**D.27** Improve ELPA detection; make abinit compatible with ELPA2019

By M. Torrent (MR 626)

**D.28** Upgrade of [[tutorial:base3]] and [[tutorial:basepar]].

By X. Gonze (MR628)

**D.29** New input variable [[prtprocar]], see test [[test:v9_108]].

By M. Verstraete (MR630)

**D.30** The ABINIT input variable [[supercell_latt]] is documented.
See also [[test:v8_94]].

By X. Gonze

**D.31** New implementation of the cRPA (to compute U and J in DFT+U or DFT+DMFT)
that can consider any subset of orbitals in the system.
Compilation was a bit long on certain compilers, so new keywords have been added to the build system:
enable_crpa_optim and enable_crpa_no_optim

By R. Outerov and B. Amadon (MR622).

**D.32** Work on refactoring the Coulomb interaction part of ABINIT.

By B. Guster, M. Giantomassi and X. Gonze (MR 627&633).

**D.33** New TB2J python script to compute the superexchange (J) and the Dzyaloshinskii-Moriya (DMI) interactions. The script can be found in [http://gitlab.abinit.org/xuhe/TB2J](http://gitlab.abinit.org/xuhe/TB2J) with doc and tutorials. The script is interfaced with wannier90 and use the w90 output files. The J calculation works in production, the DMI is much more sensitive to disentanglement noise and have to be use with care. An article is under construction to describe the method and its implementation. The script can deliver input data file for the spin model of Multibinit.

By He Xu, M. Verstraete and E. Bousquet

**D.34** Miscellaneous additional bug fixes and improvements of documentation.
L. Baguet, JM Beuken, J. Bieder, E. Bousquet, F. Bruneval, T. Cavignac, M. Giantomassi, X. Gonze, F. Jollet, N. Pike, Y Pouillon, M. Torrent, J. Van Bever, M. Verstraete, Xu He.


* * *

## v8.10

Version 8.10, released on October 15, 2018.
List of changes with respect to version 8.8.

Many thanks to the contributors to the ABINIT project between
April 2018 and October 2018. These release notes
are relative to modifications/improvements of ABINIT v8.10 with respect to v8.8.
The merge request #408 is the first MR not reported in these release notes. Then, #410-411, #413-416 have also been included.

The list of contributors includes:
B. Amadon, G. Antonius, L. Baguet, J.-M. Beuken, J. Bieder, E. Bousquet, F. Bruneval, Wei Chen, M. Cote,
J. Denier, G. Geneste, Ph. Ghosez, M. Giantomassi, O. Gingras, X. Gonze, F. Goudreault, B. Guster, Xu He, Y. Jia, F. Jollet,
A. Lherbier, A. Martin, H. Miranda, F. Naccarato, G. Petretto, N. Pike,
S. Ponce, Y. Pouillon, S. Prokhorenko, F. Ricci, M. Torrent, M. van Setten, B. Van Troeye, M. Verstraete, J. Zwanziger.

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

### A. Warnings and important remarks

A.1 The correct definition of the temperature has been implemented in the isokinetic algorithm [[ionmov]]=12.

A.2 The multibinit input variable "supercell" has been renamed "supercell_latt".

A.3 Tests v8#100-107 have been moved to v8#81-88.
    Tests paral#100-103 have been moved to paral#80-83

* * *

### B. Most noticeable achievements

B.1 The computation of the Raman intensity in DFPT with PAW is now possible (it was only available with norm conserving psps previously).
    This is based on the second-order Sternheimer equation for the derivative
    with respect to an electric field.
    See tests [[test:v8_81]] to [[test:v8_89]].
    By L. Baguet and M. Torrent.

B.2 There has been a large effort to clean the documentation, that was needed and made possible thanks to the recent move to the mkdocs system.
    In particular, many new hyperlinks have been created in dozens of markdown files,
    references have been centralized in the [[theory:bibliography]].
    By B. Amadon, G. Antonius, L. Baguet, J. Bieder, E. Bousquet, F. Bruneval, Wei Chen, M. Cote, G. Geneste,
    M. Giantomassi, X. Gonze, Xu He, F. Jollet, A. Lherbier, H. Miranda, F. Naccarato, G. Petretto, N. Pike,
    S. Ponce, Y. Pouillon, M. Torrent, M. van Setten, B. Van Troeye, M. Verstraete, J. Zwanziger.

B.3 The multibinit application (for second-principles calculations) has considerably progressed.
    Documentation has thus been set up: "topics" have been written, as well as a tutorial,
    in addition to the already existing input variable documentation and test cases.
    See [[topic:LatticeModel]], [[topic:BoundingProcess]], [[topic:FitProcess]] and [[topic:DynamicsMultibinit]],
    that are hub to the relevant tutorial, input variables and test cases
    (e.g. [[lesson:lattice_model]],[[test:v8_15]], [[test:v8_16]]...).
    By A. Martin, in collaboration with Fabio Ricci and Ph. Ghosez

B.4 Several new options are available for the [[ionmov]] input variable governing ionic dynamic or geometry optimization:

* [[ionmov]]=15 for the FIRE algorithm, [[test:v8_17]];
* for [[ionmov]]=12, isokinetic ensemble, the fixing of atomic positions is now allowed, [[test:v8_21]] and [[test:v8_22]].

Also, the documentation for the hybrid Monte Carlo algorithm has been improved, see [[test:v8_34]], and the new input variables [[hmcsst]] and [[hmctt]].

By Xu He, S. Prokhorenko and X. Gonze.

B.5 The linear combination of images is now allowed, with the new value for input variable [[imgmov]]=6,
    and mixing factor given by [[mixesimgf]].
    In this case, the total energy and forces are also assembled as a linear combination, and the geometry is optimized using
    algorithms selected with the usual [[ionmov]] input variable.
    See test [[test:v8_20]].
    The wavefunctions from the previous itimimage value (see [[ntimimage]] input variables) can be stored,
    using the new input variable [[imgwfstor]]. This allows saving CPU time at the expense of memory, in all
    the image based algorithms.
By X. Gonze, testing by Y. Jia.

B.6 Tutorial [[tutorial:nuc]]
    has now a section for the computation of the isomer shift (Mossbauer spectroscopy) based on Fermi contact interaction.
By J. Zwanziger.

B.7 The Frohlich model is now implemented in the electron-phonon part of ABINIT, [[optdriver]]=7.
    The Frohlich average of effective masses is computed with the DFPT computation of effective masses, see [[test:v8_56]].
    Also, the zero-point renormalization of the band extrema is computed using a general formula valid for isotropic and anisotropic
    solids, as well as for non-degenerate or degenerate extrema, see [[eph_frohlichm]] and [[test:v8_57]].
By X. Gonze.

* * *

### C. Changes for the developers (also compilers)

C.1 All F90 ABINIT sources are now inside modules.
    Makemake now aborts if F90 procedures outside modules.
    By M. Giantomassi, with some help by J. Zwanziger, M. Torrent and B. Amadon.

C.2 Prepared the removal of the bindings subsystem.
    By Y. Pouillon and M. Torrent.

C.2 New [Howto for developers](/developers/developers_howto) (variables, mkparents, robodoc, test_suite).
    By M. Giantomassi.

C.3 New [Howto for the test suite](/developers/testsuite_howto).
    By M. Giantomassi.

* * *

### D.  Other changes (or on-going developments, not yet finalized)

D.1 New input variable [[prtkbff]].
    This input variable activates the output of the Kleynman-Bylander form factors in the netcdf WFK file produced at the end of the ground-state calculation.
    The form factors are needed to compute the matrix elements of the commutator [Vnl, r] of the non-local part of the (NC) pseudopotentials.
    This WFK file can therefore be used to perform optical and/or many-body calculations with external codes such as DP/EXC and Yambo. The option is ignored if PAW.
By H. Miranda and M. Giantomassi.

D.2. A new routine to calculate and write the DDK matrix elements in a EVK.nc files for norm-conserving pseudo-potentials (and nspinor == 1),
    from a WFK file using the commutator [H, r] used to calculate the matrix elements for chi.
    These files are in the same format and contain the same information as the EVK.nc files (former DDK.nc) produced by the DFPT part of the code.
    This routine is parallelized over k-points and bands and requires a much smaller memory footprint than the DFPT code.
    By H. Miranda and M. Giantomassi.

D.3 New input variable [[slk_rankpp]].
    This variable controls how the number of processes to be used in Scalapack diagonalization algorithm: [[np_slk]] will be calculated according to this value.
    By J. Bieder.

D.4 New input variables [[prtefmas]], [[irdefmas]] and [[getefmas]], to deal with the effective masses, e.g. to allow feeding computed effective masses
    from one dataset to another one.
    By X. Gonze.

D.5 The spin dynamics has been implemented in multibinit.
    By He Xu.

D.6 New value for input variable [[usepawu]]=4.
    The FLL double counting is used. However, and in comparison to usepaw=1, the calculation is done without polarization in the exchange correlation functional.
By B. Amadon.

D.7 New extensive testing of the DFPT+PAW+GGA, see [[test:v8_51]].
    However, [[pawxcdev]]=0 is still needed.
    By M. Torrent.

D.8 New input variable [[prtfull1wf]] to print the full perturbed wavefunctions.
    By G. Antonius.

D.9 Allows one to suppress completion of the 2DTE for vanishing elements using symmetries only,
    negative values of [[rfmeth]].
    By X. Gonze.

D.10 Interface with TRIQS_2.0.
    By O. Gingras.

D.11 Allows to define different occupations for different spins, when [[occopt]]=0 and [[nsppol]]=2.
     By X. Gonze.

D.12 NEB is now tested (at last), [[test:v6_29]].
     By X. Gonze.

D.13 Many |abitutorials| have been improved.
     By X. Gonze.

D.14 Work on orbital magnetization.
     By J. Zwanziger.

D.15 Elastic and piezoelectric tensors in netcdf format.
     By M. Giantomassi

D.16 Allow [[boxcutmin]] for DFPT case, after check by H. Miranda.

D.17 ABIWAN.nc files with Wannier output that can be analyzed wit AbiPy.
     See the |AbiwanFileNb| for futher information.
     By M. Giantomassi.

D.18 The [[topic:Macroave]] has been created.
     By X. Gonze.

D.19. Include CTQMC Code using non diagonal hybridization function. See [[test:paral_83]].
     By B. Amadon, J. Denier and J. Bieder.

D.20. Finalize scalapack/elpa integration in lobpcg.
      Use ONLY if no openmp. Warning: scalapack is not thread-safe in general.
      By J. Bieder.

D.21 Automatic test [[test:v8_37]] for TDep application.
    By J. Bieder.

D.22 Python scripts to calculate physical properties that can be derived from the elastic tensor
     (which is the result of an anaddb calculation).
     By N. Pike.

D.23 Miscellaneous additional bug fixes and improvements of documentation.
     By B. Amadon, G. Antonius, L Baguet, J.-M. Beuken, J. Bieder, F. Goudreault, F. Jollet, H. Miranda,
     F. Nacaratto, N. Pike, M. Torrent, M. Verstraete.

* * *

## v8.8

Version 8.8, released on April 28, 2018.
List of changes with respect to version 8.6.

Many thanks to the contributors to the ABINIT project between
November 2017 and April 2018. These release notes
are relative to modifications/improvements of ABINIT v8.8 with respect to v8.6.
The merge request #285 is the first MR not reported in these release notes.

The list of contributors includes:
B. Amadon, G. Antonius, L. Baguet, J.-M. Beuken, J. Bieder, F. Bottin, Y. Bouchet, E. Bousquet, W. Chen,
C. Espejo, Ph. Ghosez, M. Giantomassi, X. Gonze, F. Jollet, A. Martin,
H. Miranda, G. Petretto, N. Pike, Y. Pouillon, S. Prokhorenko, F. Ricci,
G.-M. Rignanese, M. Torrent, M. Verstraete, J. Zwanziger

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases ...
This might take some time ...

Xavier

### A. Warnings and important remarks

A.1 Due to the availability of new input variables, some obsolete input variables have been suppressed:

* input variable cgtyphf, see now [[fockoptmix]];
* input variable gwfockmix, see now [[hyb_mixing]] and [[hyb_mixing_sr]].

A.2 The algorithm used for computing the weights for the phonon band structure interpolation in ANADDB
    in the case [[brav@anaddb]] = 1 has changed. See B.5.

A.3 Tests v7#71-72 have been moved to v7#76-77.

A.4 Replaced *tribes* by *relevance* in doc/topics.

A.5 Replace `EELF` file extension by `ELF`. See [[prtelf]].
    By Guido Petretto.

A.6 Definition of a maximal value for dilatmx, at 1.15, than can be bypassed by setting chkdilatmx=0.
    This is to prevent users slowing down ABINIT too much inadvertantly.

* * *

### B. Most noticeable achievements

B.1 The whole ABINIT documentation has been placed under the control of [mkdocs](http://www.mkdocs.org/),
    and most files have been translated to markdown
    (well, there are still a few remaining files not placed in this system, but these are quite few).
    The capabilities developed for [v8.6](#v86)
    (Topics -B.1-, central bibliography -B.2-, restructured and searcheable list of input variables -B.3-,
    frequency statistics -B.4-) have been maintained and consolidated.
    More documentation is available for developers than before. The whole system is better integrated and easier to maintain.
    The appearance is also new.
    The work on documentation is nearly complete, still not all bibliographical references of the doc have been entered in this
    central bibliographic database.
    Entry point: see the new header of any ABINIT documentation file e.g. the [new user's guide](/guide/new_user).
    By M. Giantomassi, with some help from X. Gonze.

B.2 The DFPT has been extended to non-collinear systems ([[nspden]] = 4), with or without spin-orbit coupling,
    for the ddk, electric field and atomic displacement perturbations,
    as well as for the Zeeman magnetic field perturbation (see B.3).
    See tests from [[test:v8_66]] to [[test:v8_80]]. For experts, see the new input variable [[ixcrot]].
    By F. Ricci, S. Prokhorenko, M. Verstraete, M. Torrent and E. Bousquet.

B.3 DFPT can now treat the magnetic field perturbation (Zeeman interaction - magnetic field couple to the spin).
    See the input variable [[rfmagn]], as well as tests [[test:v8_66]] to [[test:v8_70]].
    The new input variable [[tim1rev]] has been introduced, to allow treating perturbations with non-zero q wavevectors.
    By S. Prokhorenko and E. Bousquet.

B.4 The python library [AbiPy](https://github.com/abinit/abipy), for launching ABINIT (also in high-throughput mode)
    and the jupyter notebook based tutorials, nicknamed [abitutorials](https://github.com/abinit/abitutorials) are now sufficiently
    mature to be advertised. They have been used at the ICTP electron-phonon doctoral school in March 2018.
    Feedback on AbiPy and abitutorials is welcome.
    By M. Giantomassi.

B.5 A new algorithm (Wigner-Seitz cell based) for computing the weights for the phonon band structure interpolation in ANADDB
    has been implemented. It has replaced the old algorithm in case [[brav@anaddb]] = 1.
    The old algorithm is still available for back-compatibility purposes, now corresponding to [[brav@anaddb]] = -1,
    see [[test:v7_93]], although there is no real reason for using it.
    The new algorithm is very general, respect better the symmetries, and should even supercede
    the use of other values of [[brav@anaddb]].
    By G. Petretto following discussions with GM Rignanese and XGonze, and tests by Henrique Pereira Miranda.

B.6 The Chern number can be computed, in the norm-conserving case as well as in the PAW case.
    See the theory in [[cite:Ceresoli2006]].
    Associated input variable: [[orbmag]].
    Nuclear magnetic dipole moment code has been improved for efficiency. In particular,
    this improvement is due to converted nucdipmom_k to complex type and explicit BLAS call.
    Tutorial [[tutorial:nuc|nuc]] is nightly tested.
    By J. Zwanziger ([[tutorial:nuc|nuc]] testing by X. Gonze).

* * *

###C. Changes for the developers (also compilers)

C.1 Add support for NAG 6.2, use netcdf4 and hdf5 with NAG 6.2.
    New builders: abiref_nag_6.2_openmpi and atlas_gnu_7.2_fb

C.2 New version of ELPA module (2011 -> 2017 compatible)
    By M. Torrent

C.3 Replaced http://www.abinit.org by https://www.abinit.org everywhere in the doc.
    By JM Beuken

C.4 Added fake -n/--no-split option to makemake.
    This little change will let the test farm keep on working with all branches while the source tree is split into common + core.
    By Y. Pouillon

C.5 Upgrade Abinit to PSML API 1.1.
    By Y. Pouillon

C.6 Allowed for free-form link flags statements in configure options
    By Y. Pouillon

C.7 Intel 18.0 is now officially supported (one bot using it is present in the test farm).
    The situation is not perfect though, as  in mrgscr and mrgdv, the ADVANCE='NO' specification for the write instruction does not work, but
   it works in simple programs. Thus all tests (and their chain of tests) that rely on mrgscr and mrgdv have been disabled for this compiler.
   Namely, v3#87-91, vv67mbpt#37-39, v7#86-88, v8#41-44, v8#63
   Also, the reading of WFK files using MPIIO is not correct, for tests mpiio#26 and 62.

* * *

###D.  Other changes (or on-going developments, not yet finalized)

D.1 Implementation of the LDA-1/2 methodology (see the announcement B.10 of v8.6): [[test:v8_32]] has been provided.
    By F. Jollet.

D.2 Numerous progresses have been made related to the hybrid functionals (although hybrid functionals
    are not yet in production).

* Stresses are now computed correctly.

* The downsampling of the Brillouin Zone to build the Fock operator has been implemented and tested.
See the input variable [[fockdownsampling]] as well as tests [[test:libxc_72]] and [[test:paral_09]].

* The B3LYP functional has been implemented, [[ixc]] = -402.

* The new input variables [[hyb_mixing]], [[hyb_mixing_sr]], [[hyb_range_dft]], and [[hyb_range_fock]]
give sufficient flexibility in the PBE0 and HSE family of functionals.

* GW calculations can now start on top of hybrid functional calculations.

* At variance, there is also now more flexibility to run hybrid calculations using the GW infrastructure
([[gwcalctyp]] = 5, 15, 25) by the definition of the [[ixc_sigma]] input variable.

* There has been also important work concerning the self-consistency, although this work is not finalized yet
(one reason why hybrid functionals are not yet in production).
The self-consistency at fixed ACE operator can take advantage of an auxiliary XC functional to decrease
the number of inner iterations, see [[fockoptmix]], [[auxc_ixc]] and [[auxc_scal]], while for the outer loop,
in which the ACE operator is upgraded, the wavefunction mixing has been implemented ([[fockoptmix]] and [[wfmix]]).

See the new tests v7#67-72 libxc#44, 45, 72, 73, 74,
and also the updated tests v4#86, 87, v67mbpt#09, v7#65, libxc#41, 42, 43, paral#09.
By X. Gonze and F. Jollet, with help by M. Torrent.

D.3 The [[tutorial:eph_tdep_legacy|tutorial on temperature-dependence of the electronic structure]] has been upgraded, and carefully tested.
    See all tests in `tutorespfn/teph_tdep_legacy*`.
    By X. Gonze and M. Giantomassi

D.4 Output of interpolated density in the MPI-IO case is now tested, [[test:mpiio_26]] and [[test:mpiio_27]].

D.5 Ongoing work on the multibinit project.
    New input variables fit_nfixcoeff, fit_fixcoeff, fix_generateTerm,
    see [[test:v8_13]] and [[test:v8_14]].
    New input variable dipdip_prt, see [[test:v8_06]], as well as tests [[test:paral_96]] to paral[102].
    New generator for the polynomial coefficients, debug strain for the fit process, add tolerance in the fit process,
    add the plot of the comparison between model and DFT.
    By A. Martin, M. Verstraete and Ph. Ghosez.

D.6 Adjustment of tutorial tutoparal ucrpa, see test tutoparal#tucrpa_4.
    By B. Amadon

D.7 The ddk file is now available in netCDF format (lightweight version without first-order wavefunctions),
    and test with the optic post-processor has been set up.
    See the new [[test:v7_49]].
    By M. Giantomassi

D.8 Continued development of the electron-phonon [[optdriver]] = 7 module of ABINIT.
    New input variable [[tmesh]], defining a linear mesh of temperatures, see tests [[test:v8_44]] and [[test:v8_45]].
    Also, debugging and improvement of doc.
    By M. Giantomassi

D.9 Added netcdf output of phonons for full grid, not just band structure. Only in tetrahedron prtdos 2 case.
    By M. Verstraete

D.10 On-going development: main executable `atdep`, for the TDEP algorithm, by Hellman and coworkers.
     See [[src:98_main/tdep.F90]], as well as directory 80_tdep.
     No automatic tests provided yet, no documentation as well ...
     By F. Bottin, J. Bouchet, J. Bieder.

D.11 Capability to print perturbed vxc potential in response function calculations.
     By G. Antonius

D.12 On-going modularization of all source F90 files, to get rid off abilint.
     By M. Giantomassi

D.13 On-going improvements in the doc, to benefit from the new processing capabilities,
     like central bibliography, matjax, etc ...
     By M. Giantomassi, X. Gonze

D.14 Post-processing script for Raman calculations (script/post-processing/Raman_spec.py).
     Reads the anaddb output file and extracts the Raman tensor and then calculates
     the Raman spectra as a function of frequency at a user-defined temperature.
     Additionally, the script will automatically extract the dielectric tensor as a function of frequency if it is available.
     By N. Pike

D.15 Refactoring for DFPT+NON_COLL: first version for PAW
     By M. Torrent

D.16 Fix of several bugs in constrained magnetization calculations [[magconon]].
     By E. Bousquet

D.17 Wrong sign of the derivative of spherical harmonics for f orbitals.
     Can lead to problems in BSE and GW calculations if pseudos with explicit f-projectors are used.
     Detected and corrected by Henrique Pereira Miranda.
     See [[gitsha:87617d261b5905e368081af4b899b3ddd7ec83fe]] for the corrected expressions.

D.18 Add possibility to do DFT+U calculations without spin polarization
     in the exchange and correlation functional: the spin polarization thus only comes from the U and J terms.
     Can be used with [[usepawu]] = 4, but still under tests.
     By B. Amadon

D.19 GW is now available with [[nspinor]] = 2 with or without spin-orbit coupling,
    and with [[nspden]] = 1 or 4 (collinear or non-collinear spin-magnetisation).
    Implemented only in the norm-conserving case. Still under testing.
    See tests from [[test:v8_90]] to [[test:v8_93]].
    By M. Giantomassi.

D.20 Miscellaneous additional bug fixes and improvements of documentation by:
     L. Baguet, W. Chen, C. Espejo, M. Giantomassi, Y. Pouillon, M. Torrent, J. Zwanziger.


* * *

## v8.6

Many thanks to the contributors to the ABINIT project between
May 2017 and October 2017. These release notes
are relative to modifications/improvements of ABINITv8.6 with respect to v8.4.

The list of contributors includes:
B. Amadon, G. Antonius, L. Baguet, J.-M. Beuken, J. Bieder, F. Bottin, Y. Bouchet, E. Bousquet,
M. Giantomassi, O. Gingras, Ph. Ghosez, M. Giantomassi, X. Gonze, F. Jollet, J. Junquera, A. Martin,
F. Naccarato, G. Petretto, N. Pike, Y. Pouillon, S. Prokhorenko, M. Torrent, M. Verstraete, J. Wiktor, J. Zwanziger

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases.
This might take some time ...

Xavier

* * *

Version 8.6, released on November 3, 2017.

List of changes with respect to version 8.4 .

* * *

###A. Warnings and important remarks

A.1 The interface between ABINIT and TRIQS has been changed, such that TRIQS 1.4 is used now instead of TRIQS 1.3.
    No backward compatibility with TRIQS 1.3 has been coded, sorry. See D.4.

A.2 Some changes of names:

* input variable gwls_sternheimer_kmax has become [[gwls_stern_kmax]];
* input variable gwls_dielectric_model has become [[gwls_diel_model]];
* input variable prt_effpot has become prt_model (multibinit input variable);
* input variable effmass has become [[effmass_free]];
* tutorial tlda has become tdftu;

    Also, the input variable gwls_second_model_parameter, not used, has been suppressed.

A.3 The definition of Hund's coupling J as computed within cRPA has changed: it now uses the same convention as
    the convention used (for the variable [[jpawu]]) in DFT+U and DFT+DMFT in ABINIT (automatic tests, and tutorial
    are accordingly changed).
    By B. Amadon

* * *

###B.  Most noticeable achievements

B.1 The whole ABINIT documentation has been significantly improved by the introduction of Topics, replacing the
    previous "lists of ABINIT features". All the capabilities of ABINIT are now presented in about 70 short topic Web pages.
    Those topic web pages usually have:
    - a brief introduction;
    - the list of related tutorials -if any-;
    - the list of related input variables (ordered according to their importance for the topics -compulsory, basic, useful or expert-);
    - possibly example input files;
    - list of references.
    Entry point: see the new header of any ABINIT documentation file e.g. the [new user's guide](/guide/new_user)
    By F. Jollet and X. Gonze (also tests/fixes by B. Amadon, M. Torrent).

B.2 A central [[theory:bibliography]] database abiref.bib has been created, and linked to the
    above-mentioned topics (B.1) but also to other parts of the ABINIT documentation (e.g. input variable list,
    the tutorials, the theory documents, the acknowledgments).
    More than 200 bibliographical references are present.  Not all bibliographical references of the doc have been entered in this
    central bibliographic database, though.
    By X. Gonze and F. Jollet.

B.3 The list of input variables has been restructured, and is now searchable.
    The input variables for anaddb, aim and optic have been included in the database.
    By J. Bieder, X. Gonze and F. Jollet.

B.4 The frequency of usage of each input variable (in the set of automatic tests) is now automatically
    computed, and mentioned in the documentation for this input variable. Examples input files are also now mentioned in the documentation.
    The input files for the automatic tests can now be directly accessed on the Web, as well as the reference files for the tutorials.
    By. X. Gonze and F. Jollet.

B.5 Several important developments related to electron-phonon matrix element computation have been made.
    The Frohlich interpolation procedure for electron-phonon matrix elements, as explained in PRL 115, 176401 (2015), has been implemented.
    The long-range part of the phonon coupling potential is modeled with the Born effective charges and the dielectric tensor.
    This long-range part is substracted from the potential before the Fourier interpolation then added after the interpolation.
    The resulting potential is in much better agreement with the full calculation, as can be verified from the el-ph matrix elements.
    Also, a functionality has been added in the eph driver ([[eph_task]]=5) to only interpolate the phonon potential onto a fine q-point grid.
    The interpolation is performed one perturbation at a time, and is thus more memory efficient than the previous procedures.
    There is additional testing of the new "driver" optdrive=7 specifically dealing with electron-phonon
    related computations (including zero-point renormalisation), especially the interpolation.
    The symmetries have been fixed.
    See new tests [[test:v8_61]]-[[test:v8_65]].
    By  G. Antonius and M. Giantomassi.

B.6 ABINIT can now read pseudopotentials in the PSML 1.1 format, as described in https://arxiv.org/abs/1707.08938. This XML-based format is
    produced by ONCVPSP 3.2 and 3.3, as well as SIESTA's ATOM 4.2, and allows to perform calculations with the exact same pseudopotential files
    in both ABINIT and SIESTA. See the new directory ~abinit/tests/psml, tests [[test:psml_01]] to [[test:psml_14]].
    Note: patches are provided at https://launchpad.net/pspgenpatch to enable PSML output in ONCVPSP.
    By Y. Pouillon, M. Verstraete, J. Junquera and A. Garcia.

B.7 ABINIT is now interfaced with Libxc 3.0. The interface with Libxc 4.0 is in preparation.
    Tests [[test:libxc_06]], [[test:libxc_07]], [[test:libxc_17]], [[test:libxc_18]], [[test:libxc_20]], [[test:libxc_21]]
    have been modified, because some functionals of libxc v2.0 have changed category in v3.0.
    By M. Torrent.

B.8 A new tutorial, called [[tutorial:positron|Electron-positron annihilation]] has been created.
    By J. Wiktor and M. Torrent.

B.9 The new input variable [[chkdilatmx]] has been introduced, to allow expert users to make
    ABINIT bypass the stopping criterion related to dilatmx. In practice, if the condition related
    to dilatmx is not met, ABINIT continues, and delivers an (approximate) optimized geometry and energy,
    that might be used by external drivers like e.g. USPEX to continue the search for global optimized structures.
    See input variable [[chkdilatmx]], and test [[test:v3_42]].
    By X. Gonze.

B.10 Implementation of the LDA-1/2 methodology.
     Tests to be provided.
     By F. Jollet.

* * *

###C. Changes for the developers (also compilers)

C.1 There are large changes of the procedure to document ABINIT, for most of the documentation files.
    The HTML files are now produced from YAML files, under the control of the script ~abinit/doc/generate_doc.py .
    The documentation that describes this procedure is available on the ABINIT wiki, at https://wiki.abinit.org/doku.php?id=developers:generate_doc .
    This is directly linked to the modifications in the doc presented in B1-B4.
    In particular, the Dokuwiki syntax is used for the hyperlinks.
    By F. Jollet and X. Gonze.

* * *

###D.  Other changes (or on-going developments, not yet finalized)

D.1 The "Adaptively Compressed Operator" approach for the fast application of the Fock operator has been implemented,
    and replaces the traditional way to apply the Fock operator in hybrid functionals (e.g. HSE06, PBE0, ...).
    Hybrid functionals are not yet to be considered in production, though (see D.6), but likely for ABINITv8.8.
    See tests libxc 51, 52, 53, 67, 68, 69, 70, 71, and also v7#65, 66, 70.
    By F. Jollet and X. Gonze.

D.2 A set of 6 input files and accompanying references (from 32 to 2048 procs), for benchmarking high-performance computing
    is available in the new directory ~abinit/tests/hpc .
    Not yet tested automatically, but this future capability is prepared.
    By M. Torrent.

D.3 The tutorial on the temperature-dependent electronic structure has been imported from the ABINIT wiki to the
    usual location ~abinit/doc/tutorial and suppressed from the Wiki. However, it is not yet operational.
    Work is also going on on tutorial fold2bloch.
    By X. Gonze.

D.4 Interfacing with TRIQS 1.4 (instead of 1.3).
    By O. Gingras, B. Amadon and J.-M. Beuken.

D.5 Anaddb can now interpolate and print out the DDB onto an arbitrary set of q-point.
    The same procedure was used to produce the phonon band structure.
    Now, with the input variable prtddb, anaddb will produce both the _DDB file and the _DDB.nc files, the latter being separated for each q-point.
    By G. Antonius.

D.6 On-going work on hybrid functionals: speed-up of the SCF loop, computation of stresses,
    joint computation of forces and stresses, downsampling the wavevectors.
    By X. Gonze and F. Jollet.

D.7 On-going work on the implementation of the TDEP algorithm (temperature dependent sampling).
    By J. Bieder, F. Bottin and Y. Bouchet.

D.8 Replacements of http:// by https:// in many documentation files.
    By J.M. Beuken.

D.9 Test of non-magnetic DFT+U and DFT+U+SO.
    See the new test v5#16
    By M. Torrent.

D.10 Make DFT+U and local EX-exchange compatible with nspden=1/nspinor=2
     By M. Torrent.

D.11 Test of the Velocity Verlet algorithm ionmov=24
     See the new test v8#13
     By S. Prokhorenko.

D.12 Make thermally occupied supercell of a given size, with input variable thermal_supercell.
     See test v8#46
     By M. Giantomassi

D.13 Write dielectric tensor to anaddb.nc when only perturbations w.r.t. electric field are present; Test for nlflag=2,3
     Test the computation of the nonlinear coefficients and first change of dielectric tensor.
     See test v8#47-50
     By F. Naccarato.

D.14 Ongoing work: Raman intensities, in the PAW case, using DFPT.
     By L. Baguet and M. Torrent.

D.15 Ongoing work on the multibinit project.
     New hist storage.
     New tests paral#101-102, to test the anharmonic part.
     Rationalization of supercell treatment with multibinit
     By A. Martin, M. Verstraete and Ph. Ghosez.

D.16 On-going work on the extension of DFPT within non-collinear magnetism.
     By F. Ricci, S. Prokhorenko, M. Verstraete, M. Torrent and E. Bousquet.

D.17 On-going work on DFPT with magnetic field perturbation (Zeeman field).
     By S. Prokhorenko and E. Bousquet.

D.18 Begin transport epc calculations within the eph part of the code.
     By M. Verstraete.

D.19 Improvements for the reading and initialization of density (esp. nspden=4).
     By M. Torrent.

D.20 New interface to the build system and new ac8 config file format.
     By Y. Pouillon.

D.21 Store fold2bloch results in NetCDF format.
     Add new option to cut3d to convert DEN/POT from Fortran to netcdf
     By M. Giantomassi.

D.22 Add mdtemp in the _HIST file. This can be useful (mandatory) for post processing MD/PIMD
     Add imgmov in the _HIST file. Convenient to know if it is PIMD or NEB/string for postprocessing
     By J. Bieder.

D.23 Use inversion symmetry if nspden == 4 and NC
     By M. Giantomassi.

D.24 Update elastic tutorial
     By J. Zwanziger.

D.25 Add LO-TO terms to netcdf files
     By M. Giantomassi.

D.26 Numerous miscellaneous additional bug fixes and improvements of documentation by:
     G. Antonius, J. Bieder, M. Giantomassi, F. Jollet,
     G. Petretto, N. Pike, Y. Pouillon, M. Verstraete, M. Torrent.

* * *

## v8.4

Many thanks to the contributors to the ABINIT project between
January 2017 and May 2017.
These release notes are relative to modifications/improvements of ABINITv8.4 with respect to v8.2.

The list of contributors includes:
F. Altvater, G. Antonius, L. Baguet, J.-M. Beuken, J. Bieder, E. Bousquet,
W. Chen, G. Geneste, M. Giantomassi, Y. Gillet, X. Gonze, F. Jollet, A. Martin,
F. Naccarato, G. Petretto, S. Prokhorenko, F. Ricci, M. Torrent, M. Verstraete, J. Zwanziger

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases ...
This might take some time ...

Xavier

* * *

Version 8.4, released on June 2, 2017.

List of changes with respect to version 8.2 .

* * *

A.  Warnings and important remarks

A.1 The Github ABINIT Web page, at https://github.com/abinit, allows one to
    access the mirror of the repository of ABINIT, as well as some other projects
    related to ABINIT, like AbiPy or the pseudo-dojo.

A.2 The content of the ABINIT Web portal, specifically for the pages related to the presentation of
    ABINIT (http://www.abinit.org/about/what-is-abinit), has been upgraded.

* * *

B.  Most noticeable achievements

B.1 Implementation of algorithms to interpolate the electronic band structure,
    based either on "star functions" of on "B-splines" (as alternatives to Wannier function interpolation).
    See the input variables [[einterp]], [[nkpath]], and [[prtebands]], and tests
    old syntax: `Tlibxc#42, Tv8#04` replaced by
    [[tests/libxc/Input/t41.abi]], [[test:v8_04]].
    Work by M. Giantomassi

B.2 The Fock mixing factor for the HSE hybrid functional can be tuned thanks to the input variable gwfockmix.
    (Warning: this is for the GW-type approach to electronic structure only, not for total energies)
    See test Tlibxc#43 .
    Work by W. Chen.

B.3 Implementation of spatially-varying chemical potential, for each atomic species.
    See the input variables [[chempot]] and [[nzchempot]], and tests Tv8#30 and 31.
    Work by X. Gonze

B.4 Linear geometrical constraints can now be imposed on PIMD runs.
    This allows ABINIT to use the blue moon sampling technique.
    See the input variable pimd_contraint, and test Tv8#05
    The use of history (HIST) files is now possible with images.
    Work by G. Geneste and M. Torrent.

B.5 Computation of linear reponse (optics executable as well as BSE part of ABINIT)
    in the case of temperature-dependent electronic structure.
    See tests Tv67mbpt#50-53.
    WARNING: This capability of ABINIT has not been fully tested. However, the
    basic tests for non-spin-polarized simple semiconductors are OK.
    As usual, use at your own risk.
    Work by Y. Gillet and M. Giantomassi.

B.6 Computation of Gruneisen parameters by finite differences, within ANADDB.
    See test v8#45
    Work by M. Giantomassi

B.7 New LOBPCG implementation [[wfoptalg]] = 114.
    This is the default when [[paral_kgb]] == 1.
    Performances are equivalent in standard use (MPI alone) and much better with openmp+multithreaded linalg.
    It also allows to have only one block for large system and to reduce memory copies.
    This version has been developed keeping in mind the next generation of HPC.
    Work by J. Bieder

B.8 New algorithms for the displacement of nuclei ([[ionmov]]):
    - Hybrid Monte Carlo (HMC) predictor (ionmov=25)
    - Velocity Verlet (VV) NVE molecular dynamics predictor (ionmov=24)
    See Tv8#12 for ionmov=24.
    Work by S. Prokhorenko

B.9 Refactoring of ANADDB for the production of DOS and other thermodynamic quantities,
    also the mean square displacement and mean square velocity.
    The DOS is obtained using usual DOS methods, instead of the histogram method,
    and converges much faster with [[anaddb:ng2qpt]]. Activated with [[anaddb:prtdos]] 1 or 2 in anaddb.
    Work by M. Verstraete.

* * *

C. Changes for the developers (also compilers)

C.1 Management of the test farm: the new bot ubu_intel_17_openmpi
    has been activated, so that Intel 17 is now supported.
    Also, replacement of shiva_gnu_6.3_py3k by inca_gnu_6.3_py3k,
    update of graphene (MacPorts) to gcc6.3 + scalapack.
    By J.M. Beuken.

* * *

D.  Other changes (or on-going developments, not yet finalized).

D.1 The printing of potentials (e.g. [[prtvxc]] ...) works now for DFPT.
    By M. Verstraete.

D.2 New input variable [[prtphbands]].
    See tests v7#88 and v8#46.
    By M. Giantomassi

D.3 In case the ANADDB interpolation of phonon frequencies produces
    erroneously a negative slope around gamma, the new [[anaddb:nsphere]] = -1 possibility
    allows ANADDB to select a set of IFCs that does not lead to such non-physical behaviour.
    See test v8#46.
    Work by M. Giantomassi.

D.4 Added new value for [[anaddb:nlflag]] = 3 that computes only the non-linear susceptibility.
    By F. Naccarato.

D.5 Computation of forces is now possible in the Wavelets + PAW case.
    By M. Torrent.

D.6 Ongoing work concerning the new "driver" [[optdriver]] = 7 specifically dealing with electron-phonon
    related computations (including zero-point renormalisation).
    See new tests v8#41 to 44.
    Work by M. Giantomassi.

D.7 Ongoing work: Raman intensities, in the PAW case, using DFPT.
    By L. Baguet and M. Torrent

D.8 Ongoing work related to non-collinear DFPT.
    Definition of the new input variable [[rfmagn]], as well as Tv8#20 .
    DFPT with static B-field (Zeeman term only) works for q=(0 0 0).
    Adjustmanet of dfpt corrections for metals to non-collinear case.
    Bug fix for GS calculations with finite magnetic field (case of collinear spins).
    By S. Prokhorenko, F. Ricci, and E. Bousquet

D.9 Ongoing work on the multibinit project.
    NPT simulations are possible.
    New tests v8#06 and paral#100, to check the correct IO of XML files.
    Note that tests Tv7#120-124 have been renumbered Tv8#07-11.
    Work by A. Martin

D.10 New test paral#62, to make sure [[paral_kgb]] = 0 works when there are some idle procs.
     By M. Giantomassi

D.11 Ongoing work on forces and stresses for hybrid functionals.
     By F. Jollet

D.12 Ongoing work on the electron-phonon postprocessor ElectronPhononCoupling.
     Fix bug affecting MPI runs.
     By G. Antonius.

D.13 Improvement of zheevd using MAGMA (from a msg on the forum)
     By M. Torrent

D.14 Implemented KSS.nc output with netcdf primitives
     By M. Giantomassi

D.15 Concerning  the Fourier interpolation of the phonon band structure,
     inside ANADDB, work by G Petretto:
     - Updates in the calculation of sound velocity,
     - Small modifications for [[anaddb:nlflag]] == 3 and added some quantities to the anaddb netcdf file,
     - Fix a bug in the implementation of the new weights

D.16 Concerning Path Integral Molecular Dynamics with Quantum Thermal Bath:
     allow restart from history file.
     By M. Torrent

D.17 Refactored the computation of the electric dipole moment.
     By M. Torrent

D.18 The energy width for the bands in the Boltztrap intrans file is now automatically set.
     Previously a constant 0.4 Ryd, and the user should have checked by hand if
     the value was sufficient. Should be considered a bug fix.
     By M Verstraete

D.19 Numerous miscellaneous additional bug fixes and improvements of documentation by:
     F. Altvater, G. Antonius, J. Bieder, M. Giantomassi, F. Jollet,
     G. Petretto, M. Verstraete, M. Torrent, J. Zwanziger.

* * *

## v8.2

Many thanks to the contributors to the ABINIT project between
June 2016 and January 2017. These release notes
are relative to modifications/improvements of ABINITv8.2 with respect to v8.0.

Moreover, most of them are also described in the Computer Physics Communications 2016 ABINIT paper,
doi:10.1016/j.cpc.2016.04.003

The list of contributors includes:
B. Amadon, G. Antonius, L. Baguet, J.-M. Beuken, J. Bieder, E. Bousquet, F. Bruneval,
W. Chen, M. Giantomassi, Y. Gillet, X. Gonze, G. Petretto, F. Jollet, A. Martin,
V. Planes, Y. Pouillon, T. Rangel, F. Ricci, M. Torrent, M. Verstraete

It is worth to read carefully all the modifications that are mentioned in the present file,
and examine the links to help files or test cases ...
This might take some time ...

Xavier

* * *

Version 8.2, released on February 16, 2017.

List of changes with respect to version 8.0 .

* * *

A.  WARNINGS AND IMPORTANT REMARKS

A.0 The 2016 article by the ABINIT group is now mentioned in the acknowledgments:
    "Recent developments in the ABINIT software package.
    Computer. Phys. Communications 205, 106 (2016)".
    See http://www.abinit.org/doc/helpfiles/for-v8.2/users/acknowledgments.html, as well as
    the notice at the end of ABINIT runs.

A.1 [[inclvkb]] 1 has been removed. Now the possible values are either 0 or 2

A.2 The default strategy of [[so_psp]] has been changed
    (see the description of the input variable so_psp).

* * *

B.  Most noticeable achievements

B.1 Implementation of the Limited-memory Broyden-Fletcher-Goldfarb-Shanno (LBFGS)
    minimization algorithm.  Activate this algorithm using [[ionmov]] = 22.
    From the tests that have been run, this algorithm can be much better
    than the native implementation of BFGS in ABINIT when one approaches convergence,
    perhaps because of better treatment of numerical details.
    This algorithm might become the default in ABINIT, if the better behaviour is confirmed.
    Test case: v8#02 .
    The working routines were based on the original implementation of J. Nocedal
    available on netlib.org.  They have been reshaped and translated into modern fortran,
    then interfaced to ABINIT by F. Bruneval (sources in 45_geomoptim/m_lbfgs.F90).

B.2 A new tutorial is available, on the calculation of the effective interactions U and J
    using constrained Random Phase Approximation (cRPA) for DFT+DMFT (or DFT+U) calculations.
    See doc/tutorial/_ucalc_crpa.md as well as the automatic tests tutorial/tucrpa#1-5 .
    This tutorial was prepared by B. Amadon.

B.3 Implementation of temperature-dependent spectral functions
    (electronic spectral function, with electron-phonon interactions),
    as well as real part of phonon self-energy (Pi) for gapped systems.
    Also, automatic test for spectral function, v7#89, and improved documentation.
    Work by G. Antonius.

B.4 The RPA one-shot bootstrap fxc kernel has been implemented for GW calculations (gwgamma=-8).
    See Rigamonti et al PRL 114, 146402 (2014) and Berger PRL 115, 137402 (2015).
    The test v67mbpt#36 has been updated.
    Work by W. Chen.

* * *

C. Changes for the developers (also compilers)

C.1 The version control system that is used for the development of ABINIT has been changed:
    the whole ABINIT project
    has been ported from bzr to git.
    Work by J.-M. Beuken, Y. Pouillon, M. Giantomassi, X. Gonze,
    with discussions with many developers.

C.2 New versions of Fortran compilers have been integrated in the test farm:
    - intel 16.0
    - gnu 6.1 and 6.2
    - IBM xlf compiler 14.1
    - NAG 5.3
    Corresponding examples are available in doc/build/config-examples.
    On the contrary, g95 is not tested anymore.
    Work by J.-M. Beuken

C.3 The v8 directory for tests has been initialized.
    By Matteo Giantomassi.

C.4 Python 3 >= 3.4 is now supported in build system scripts
    (compatibility with py2_ version >= is maintained).
    By Matteo Giantomassi.

* * *

D.  Other changes
(or on-going developments, not yet finalized).

D.1 The main executable "multibinit" has been created.
    Its goal is to perform "second-principles calculations", building model Hamiltonians
    using the data provided by the DDB (or other info from ABINIT).
    Tests v7#120-124 (should be renamed) as well as paral#95-98.
    Work by A. Martin.

D.2 A new "driver" within ABINIT has been defined, specifically dealing with electron-phonon
    related computations (including zero-point renormalisation).
    Set optdriver=7 .
    New input variables: ddb_shiftq, eph_task, eph_transport, prtphdos, prtphsurf.
    See tests v7#88 and 89.
    Work by M. Giantomassi and G. Antonius.

D.3 The generation of k-point meshes with kptrlatt and shiftk is now tested.
    See test v8#03 .
    Work by M. Giantomassi

D.4 As a follow-up of the Achievement B3 in the release notes of ABINITv8.0 (DMFT + TRIQS),
    new input variables have been defined for DMFT: dmft_tolfreq and dmftctqmc_triqs_nleg.
    Automatic tests have been set-up, tests v8#01 and paral#99.
    Work by B. Amadon and V. Planes

D.5 More systematic tests of the IO in parallel (different files) have been set up,
    in the norm-conserving, PAW and PAW + spin-orbit cases.
    See tests mpiio#26, 27 and 28.
    Also, the case [[paral_kgb]] = 0 is now tested with idle processors. See test paral#62.
    Work by M. Giantomassi

D.6 The load balancing for the repartition of the plane waves among procs is now monitored,
    and a dynamical equilibration is made possible thanks to the new input variable pw_unbal_thresh.
    See test mpiio#26.
    Work by M. Torrent

D.7 The capability to output spin-resolved DOS in case of spin-orbit NC pseudopotential
    calculations has been checked, and a test has been set-up (test v7#17).
    Work by M. Giantomassi

D.8 Files generated by ABINIT, and used by BOLTZTRAP are now tested.
    See v6#11.
    Work by M. Giantomassi

D.9 Unit tests (fftprof) have been set up for the use of the MKL-DFTI routines:
    unitary#tfftmkl_03 and 04.
    Work by M. Giantomassi

D.10 Ongoing work: Raman intensities, in the PAW case, using DFPT.
     By L. Baguet and M. Torrent

D.11 prtvcbm working with all parallelizations.
     Tests mpiio 26:28 have been reactivated on 4 processors.
     By M. Torrent

D.12 On going work related to non-collinear DFPT.
     By F. Ricci, S. Prokhorenko, and E. Bousquet

D.13 MBPT: support for the commutator [Vnl r] in the case of NC pseudos
     with more than one projector per l-channel has been added.
     Tests in v67mbpt[40] (GW run with psp8 files).
     SOC is not yet available, though.
     The KSS file continues to use the old implementation to maintain backward compatibility
     hence outkss won't produce the file if multiple-projectors are detected
     inclvkb 1 has been removed. Now the possible values are either 0 or 2
     By M Giantomassi

D.14 For Hirshfeld and Bader: doc and warning.
     For Hirshfeld charges the output was unclear: the density integral (electrons only)
     was called the hirshfeld charge, as opposed to the net one.
     For Bader there was no check that the core charge file
     corresponded to the pseudopotential used.
     Now checks at least that it integrates to znucl-zion, which is a first step.
     Important as the default fc files on the web do not have semicore electrons,
     whereas many of the psp8 will.
     Contribution by M. Verstraete.

D.15 Updated acknowledgments, including the 2016 paper.
     By X. Gonze

D.16 Ongoing work on forces and stresses for hybrid functionals.
     By F. Jollet

D.17 Ongoing work concerning weights for the Fourier interpolation inside ANADDB.
     By G. Petretto

D.18 Numerous miscellaneous additional bug fixes
     (to the sources, as well as to the build system, including patches for the fallbacks),
     and improvements of documentation by:
     G. Antonius, L. Baguet, J. Bieder, F. Bruneval,
     M. Giantomassi, Y. Gillet, G. Petretto, Y. Pouillon,
     M. Verstraete, M. Torrent (in particular, for DFPT+PAW).

* * *