=========== erfa_python

This is a Python wrapper for ERFA, Essential Routines for Fundamental Astronomy, a library derived and 'freed' from SOFA, Standards of Fundamental Astronomy.

ERFA : https://github.com/liberfa/erfa

SOFA : http://www.iausofa.org

requirements

to use this wrapper, you need:

Python 2.7 - 3.6
C compiler to build the module.

. newer version of gcc (4.7+) is prefered.

obtaining

download tarball

latest version is available from pypi:

https://pypi.python.org/pypi/erfa_python

or from github:

https://github.com/nirinA/erfa_python/releases

clone from github

you can clone the project repository at:

https://github.com/nirinA/erfa_python/

building

to build the module, unpack the tarball, cd to erfa_python directory and do the usual:

    python setup.py build

note for OS X:

on OSX platform, it seems that erfa needs to be build as a library, and some 'compatibility version' needs to be adjusted thanks to @vhaasteren for reporting and solving this issue, see:

https://github.com/nirinA/erfa_python/issues/4

installing

if previous version of erfa_python is already installed in site-packages, be sure to remove all related files before installing the new version.
install (may need root privilege) with:

    python setup.py install

testing

a test-suite adapted from t_erfa_c.c is provided. do:

    python erfa_test.py

to validate erfa_python module.

note:

some test fail with older version of gcc (4.5). thanks to @yanwang2012 for this report, see:

https://github.com/nirinA/erfa_python/issues/6

documentation

on-line documentation is available with:

    pydoc erfa

to generate a html version:

    pydoc -w erfa

and, from the interpreter:

   >>> help(erfa)
   >>> help(erfa.<function>)

to be updated

more detailed C-api reference of liberfa is available in doc/api.rst. a html version can be built:

    cd doc   
    mkdir _build  
    sphinx-build . _build

you need sphinx and its dependencies to build the doc.

examples

some examples adapted from SOFA documentation can be found in examples/ directory.

. ex_ast.py

example of Astrometry Tools

. ex_pn.py

example of tools for Earth Attitude

. ex_ts.py

example of Time Scale and Calendar Tools

. ex_ephem.py

basic example of Ephemerids for Sun and Major planets

what's new

. 2010201

update from SOFA release 14.

. 20170421

update from SOFA release 13.
this release replaces the IAU 1976 value of astronomical unit with the IAU 2012 value.
codes are all backward compatible but results are not, especially those using erfa.ASTROM
erfa_test.py has been updated accordingly

. 2016123

update from SOFA release 12, revised on 2016-12-23.
tests for fk52h and starpm are relaxed, as they failed with Python3.6 built with all optimization enabled.

. 20160503

add new routines from SOFA release 12.

. 20150211

add new functions icrs2g and g2icrs from latest SOFA release

. 20141016

upload a windows binary to PyPi.

. 20140921

update erfa.c from latest sofa release.

. 20140601

erfa source is included, so a pre-installed liberfa is no longer required.

. 20140530

update ex_ast.py
fix _erfamodule.c docstring

. 20140127

support for Python-3.4.

. 20131226

completed routines from the latest SOFA release.
renamed and slightly reworked the C extension to _erfamodule.c

. 20131222

added a few routines from the latest SOFA release.

. 20130830

registered to PyPi

. 20130815

rewrote the wrapper from SOFA to ERFA

nirinA / erfa_python

readme