1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156
|
This is the source code repository for ERFA (Essential Routines for
Fundamental Astronomy). ERFA is a C library containing key algorithms for
astronomy, and is based on the `SOFA library <http://www.iausofa.org/>`_ published by the International
Astronomical Union (IAU).
ERFA is intended to replicate the functionality of SOFA (aside from possible
bugfixes in ERFA that have not yet been included in SOFA), but is licensed
under a three-clause BSD license to enable its compatibility with a wide
range of open source licenses. Permission for this release has been
obtained from the SOFA board, and is available in the ``LICENSE`` file included
in this source distribution.
Differences from SOFA
---------------------
This version of ERFA (v1.7.2) is based on SOFA version "20210125", with the
differences outlined below.
ERFA branding
^^^^^^^^^^^^^
All references to "SOFA" in the source code have been changed to ERFA, and
functions have the prefix ``era`` instead of ``iau``.
C macro prefixes
^^^^^^^^^^^^^^^^
All C macros used in ERFA are the same as their SOFA equivalents, but with an
``ERFA_`` prefix to prevent namespace collisions.
Version information
^^^^^^^^^^^^^^^^^^^
ERFA provides a few utility functions for accessing version information at
runtime which are not a part of SOFA. Specifically, these are the
``eraVersion``, ``eraVersion*``, and ``eraSofaVersion`` functions that are
exposed in the ``erfaextra.h`` header.
Runtime leap second modification
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ERFA provides the capability to modify at runtime the leap seconds assumed for
various calculations. These are accessed via the ``eraGetLeapSeconds`` and
``eraSetLeapSeconds`` functions that are exposed in the ``erfaextra.h`` header.
This functionality is currently considered somewhat experimental, meaning an
improved API might be available in the future, but the current API can also be
counted on for the near future.
Bug fixes
^^^^^^^^^
ERFA includes smaller changes that may or may not eventually make it into SOFA,
addressing localized bugs or similar smaller issues:
* ERFA 1.7.2 and SOFA "20210125"
+ Only bug and accuracy fixes in the SOFA release. The only differences
between ERFA 1.7.2 and SOFA "20210125" remain the added ``eraVersion``,
``eraSofaVersion``, and leap second functions noted above.
* ERFA 1.7.1 and SOFA "20200721"
+ Only bug fixes in the SOFA release. The only differences between ERFA 1.7.1
and SOFA "20200721" remain the added ``eraVersion``, ``eraSofaVersion``, and
leap second functions noted above.
* ERFA 1.7.0 and SOFA "20190722"
+ There are no differences between ERFA 1.7.0 and SOFA "20190722" except
for the added ``eraVersion``, ``eraSofaVersion``, and leap second functions
noted above.
* ERFA 1.6.0 and SOFA "20190722"
+ There are no differences between ERFA 1.6.0 and SOFA "20190722" except
for the ``eraVersion`` and ``eraSofaVersion`` functions added in ERFA 1.4.0.
* ERFA 1.5.0 and SOFA "20180130"
+ There are no differences between ERFA 1.5.0 and SOFA "20180130" except
for the ``eraVersion`` and ``eraSofaVersion`` functions added in ERFA 1.4.0.
* ERFA 1.4.0 and SOFA "20170420"
+ ERFA 1.4.0 adds the ``eraVersion`` and ``eraSofaVersion`` functions to
determine the installed version of ERFA (and the SOFA version it is derived
from).
+ ERFA 1.4.0 includes some bug fixes contributed to ERFA after 1.3.0 but
before 1.4.0. These were incorporated (with modification) into
SOFA "20170420" (without attribution) and hence these are not differences
between ERFA and SOFA. (See https://github.com/liberfa/erfa/issues/40 and
https://github.com/liberfa/erfa/issues/41)
* ERFA 1.3.0 and SOFA "20160503_a"
+ There are no differences between ERFA 1.3.0 and SOFA "20160503_a".
* ERFA 1.2.0 and SOFA "20150209_a"
+ Typos have been corrected in the documentation of atco13 and atio13 (see https://github.com/liberfa/erfa/issues/29).
Note that issues identified in ERFA should generally also be reported upstream to SOFA at sofa@ukho.gov.uk.
Building and installing ERFA
----------------------------
To build and install a released version of ERFA in your OS's standard
location, simply do::
./configure
make
make install
If you want to run the tests to make sure ERFA built correctly, before
installing do::
make check
For developers
^^^^^^^^^^^^^^
If you are using a developer version from github, you will need to first do
``./bootstrap.sh`` before the above commands. This requires ``autoconf`` and
``libtool``.
If you wish to build against the ERFA static library without installing, you
will find it in ``$ERFAROOT/src/.libs/liberfa.a`` after running ``make``.
Creating a single-file version of the source code
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Alternatively, if you wish to bundle the ERFA source code with a separate
package, you can use the ``source_flattener.py`` script from the
`erfa-fetch repository`_ to combine
the ERFA source code into just two files: a ``erfa.c`` source file, and an
``erfa.h`` include file. You should run this script like this::
cd /path/to/erfa-source-code
python /path/to/erfa-fetch/source_flattener.py src -n erfa
If possible, however, it is recommended that you provide an option to use any
copy of the ERFA library that is already installed on the system.
Travis build status
-------------------
.. image:: https://travis-ci.org/liberfa/erfa.png
:target: https://travis-ci.org/liberfa/erfa
.. _erfa-fetch repository: https://github.com/liberfa/erfa-fetch
Cite As
-------
.. image:: https://zenodo.org/badge/DOI/10.5281/zenodo.3564896.svg
:target: https://doi.org/10.5281/zenodo.3564896
|