#!/bin/sh

# run from directory where this script is
cd `echo $0 | sed 's/\(.*\)\/.*/\1/'` # extract pathname
EXAMPLE_DIR=`pwd`

# check whether ECHO has the -e option
if test "`echo -e`" = "-e" ; then ECHO=echo ; else ECHO="echo -e" ; fi

$ECHO
$ECHO "$EXAMPLE_DIR : starting"
$ECHO
$ECHO "This example shows how to use pw.x and hp.x to calculate"
$ECHO "the Hubbard U parameters for Ni and Mn in Ni2MnGa."

# set the needed environment variables
. ../../../environment_variables

# required executables and pseudopotentials
BIN_LIST="pw.x hp.x"
PSEUDO_LIST="Ni.pbesol-n-rrkjus_psl.0.1.UPF Mn.pbesol-spn-rrkjus_psl.0.3.1.UPF Ga.pbesol-dn-rrkjus_psl.0.2.UPF"

$ECHO
$ECHO "  executables directory: $BIN_DIR"
$ECHO "  pseudo directory:      $PSEUDO_DIR"
$ECHO "  temporary directory:   $TMP_DIR"
$ECHO
$ECHO "  checking that needed directories and files exist...\c"

# check for directories
for DIR in "$BIN_DIR" "$PSEUDO_DIR" ; do
    if test ! -d $DIR ; then
        $ECHO
        $ECHO "ERROR: $DIR not existent or not a directory"
        $ECHO "Aborting"
        exit 1
    fi
done
for DIR in "$TMP_DIR" "$EXAMPLE_DIR/results" ; do
    if test ! -d $DIR ; then
        mkdir $DIR
    fi
done
cd $EXAMPLE_DIR/results

# check for executables
for FILE in $BIN_LIST ; do
    if test ! -x $BIN_DIR/$FILE ; then
        $ECHO
        $ECHO "ERROR: $BIN_DIR/$FILE not existent or not executable"
        $ECHO "Aborting"
        exit 1
    fi
done
$ECHO " done"

# check for pseudopotentials
for FILE in $PSEUDO_LIST ; do
    if test ! -r $PSEUDO_DIR/$FILE ; then
       $ECHO
       $ECHO "Downloading $FILE to $PSEUDO_DIR...\c"
            $WGET $PSEUDO_DIR/$FILE $NETWORK_PSEUDO/$FILE 2> /dev/null
    fi
    if test $? != 0; then
        $ECHO
        $ECHO "ERROR: $PSEUDO_DIR/$FILE not existent or not readable"
        $ECHO "Aborting"
        exit 1
    fi
done
$ECHO " done"

# how to run executables
PW_COMMAND="$PARA_PREFIX $BIN_DIR/pw.x $PARA_POSTFIX"
HP_COMMAND="$PARA_PREFIX $BIN_DIR/hp.x $PARA_POSTFIX"
$ECHO
$ECHO "  running pw.x as:   $PW_COMMAND"
$ECHO "  running hp.x as:   $HP_COMMAND"
$ECHO

# clean TMP_DIR
$ECHO "  cleaning $TMP_DIR...\c"
rm -rf $TMP_DIR/*
$ECHO " done"

PREFIX='Ni2MnGa'

# The PWscf self-consistent calculation
cat > $PREFIX.scf.in << EOF
 &control
    calculation='scf'
    restart_mode='from_scratch',
    prefix='$PREFIX'
    pseudo_dir = '$PSEUDO_DIR/'
    outdir='$TMP_DIR/'
    verbosity='high'
 /
 &system
    ibrav = 7,
    celldm(1) = 7.80,
    celldm(3) = 1.4142136,
    nat = 4, 
    ntyp = 3,
    ecutwfc = 50.0
    ecutrho = 400.0
    occupations ='smearing',
    smearing ='mv'
    degauss = 0.01,
    nspin = 2,
    starting_magnetization(1) = 0.5
    starting_magnetization(2) = 0.5
    lda_plus_u = .true.,
    lda_plus_u_kind = 0,
    U_projection_type = 'ortho-atomic',
    Hubbard_U(1) = 1.d-8
    Hubbard_U(2) = 1.d-8
 /
 &electrons
    conv_thr =  1.d-15
    mixing_beta = 0.7
 /
ATOMIC_SPECIES
 Mn  54.938  Mn.pbesol-spn-rrkjus_psl.0.3.1.UPF 
 Ni  58.693  Ni.pbesol-n-rrkjus_psl.0.1.UPF 
 Ga  69.723  Ga.pbesol-dn-rrkjus_psl.0.2.UPF
ATOMIC_POSITIONS {crystal}
 Mn 0.0000000000   0.0000000000   0.0000000000
 Ni 0.5000000000   0.7500000000   0.2500000000 
 Ni 0.5000000000   0.2500000000   0.7500000000 
 Ga 0.0000000000   0.5000000000   0.5000000000
K_POINTS {automatic}
 4 4 4 0 0 0
EOF
$ECHO "  Running the SCF calculation for $PREFIX..."
$PW_COMMAND < $PREFIX.scf.in > $PREFIX.scf.out
$ECHO " done"

# Perturbation of Mn : calculation for q points from 1 to 2
cat > $PREFIX.hp.Mn.step1.in << EOF
 &inputhp
   prefix = '$PREFIX',
   outdir = '$TMP_DIR/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   conv_thr_chi = 1.0d-8,
   iverbosity = 2
   perturb_only_atom(1) = .true.
   start_q = 1
   last_q  = 2
 /
EOF
$ECHO "  Running the linear-response calculation of Hubbard U..."
$HP_COMMAND < $PREFIX.hp.Mn.step1.in > $PREFIX.hp.Mn.step1.out
$ECHO " done"


# Perturbation of Mn : calculation for q points from 3 to 4
cat > $PREFIX.hp.Mn.step2.in << EOF
 &inputhp
   prefix = '$PREFIX',
   outdir = '$TMP_DIR/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   conv_thr_chi = 1.0d-8,
   iverbosity = 2
   perturb_only_atom(1) = .true.
   start_q = 3
   last_q  = 4
 /
EOF
$ECHO "  Running the linear-response calculation of Hubbard U..."
$HP_COMMAND < $PREFIX.hp.Mn.step2.in > $PREFIX.hp.Mn.step2.out
$ECHO " done"


# Perturbation of Mn : collection of q points from 1 to 4
# and calculation of one column in chi0 and chi
cat > $PREFIX.hp.Mn.step3.in << EOF
 &inputhp
   prefix = '$PREFIX',
   outdir = '$TMP_DIR/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   iverbosity = 2
   perturb_only_atom(1) = .true.
   sum_pertq = .true.
 /
EOF
$ECHO "  Running the linear-response calculation of Hubbard U..."
$HP_COMMAND < $PREFIX.hp.Mn.step3.in > $PREFIX.hp.Mn.step3.out
$ECHO " done"


# Perturbation of one Ni : calculation for q points from 1 to 2
cat > $PREFIX.hp.Ni.step1.in << EOF
 &inputhp
   prefix = '$PREFIX',
   outdir = '$TMP_DIR/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   conv_thr_chi = 1.0d-8,
   iverbosity = 2
   perturb_only_atom(2) = .true.
   start_q = 1
   last_q  = 2
 /
EOF
$ECHO "  Running the linear-response calculation of Hubbard U..."
$HP_COMMAND < $PREFIX.hp.Ni.step1.in > $PREFIX.hp.Ni.step1.out
$ECHO " done"


# Perturbation of one Ni : calculation for q points from 3 to 4
cat > $PREFIX.hp.Ni.step2.in << EOF
 &inputhp
   prefix = '$PREFIX',
   outdir = '$TMP_DIR/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   conv_thr_chi = 1.0d-8,
   iverbosity = 2
   perturb_only_atom(2) = .true.
   start_q = 3
   last_q  = 4
 /
EOF
$ECHO "  Running the linear-response calculation of Hubbard U..."
$HP_COMMAND < $PREFIX.hp.Ni.step2.in > $PREFIX.hp.Ni.step2.out
$ECHO " done"


# Perturbation of one Ni : collection of q points from 1 to 4
# and calculation of one column in chi0 and chi
cat > $PREFIX.hp.Ni.step3.in << EOF
 &inputhp
   prefix = '$PREFIX',
   outdir = '$TMP_DIR/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   iverbosity = 2
   perturb_only_atom(2) = .true.
   sum_pertq = .true.
 /
EOF
$ECHO "  Running the linear-response calculation of Hubbard U..."
$HP_COMMAND < $PREFIX.hp.Ni.step3.in > $PREFIX.hp.Ni.step3.out
$ECHO " done"


# Final step: collect all pieces of the response matrices 
# chi0 and chi1, invert them and calculate U for Mn and Ni
cat > $PREFIX.hp.final.in << EOF
 &inputhp
   prefix = '$PREFIX',
   outdir = '$TMP_DIR/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   iverbosity = 2
   compute_hp = .true.
 /
EOF
$ECHO "  Running the linear-response calculation of Hubbard U..."
$HP_COMMAND < $PREFIX.hp.final.in > $PREFIX.hp.final.out
$ECHO " done"