Downloading PyARTS
------------------

I think you have already downloaded PyARTS succesfully, but otherwise,
PyARTS is available by svn from the ARTS website http://www.sat.ltu.se/arts/tools.

Prerequisites
-------------

Note: those are the versions that PyARTS was most recently developed and
tested with. It may work with older versions and probably will work with newer
versions (possibly with minor changes).

   * Python 2.6, <http://www.python.org> (you will probably have this already)
     - Note: PyARTS does not work with Python 3.

   * A fortran compiler

   * NumPy 1.3.0

   * SciPY 0.7.2

   * matplotlib 0.99.3 <http://matplotlib.sourceforge.net/>

   * To build the documentation: docutils (Ubuntu: python-docutils)

Installation
------------

Once you have all of the above prerequisites installed, and checked
out PyARTS from the svn repository, run the following from the base directory.

python setup.py install --user

This will install the package in ~/.local/lib and also it will put some
required scripts in ~/.local/bin.
Do not try to add the PyARTS repository to your PYTHONPATH directly. It won't work. You need
to install PyARTS first, because some parts need to be compiled (such as the
*tmatrix* module).
If you omit the --user argument python will try and install the modules
in the standard 3rd party location (something like
/usr/lib/python2.6/site-packages), which obviously won't happen unless
you have superuser privileges

In most cases the install command above will work, however,
if it cannot find numpy or scipy, you will need to tell it where to find it:

python setup.py build_src build_ext
--include-dirs=<wherever>/include/python install --user

Once installed you should make sure that the PATH environment variable
includes ~/.local/bin and the ARTS_PATH environment variable points to the
arts executable, if this is not in the PATH already.

Some functionality requires certain paths to be set. To make sure ARTS can
find this, set the environment variable ARTS_XMLDATA_PATH to your
arts-xml-data repository and copy the example_config to ~/.PyARTSrc and
edit this accordingly.

Testing your Installation
-------------------------

There are several unit tests in the test/ folder of the distribution.
These test both the functionality and the accuracy of the software. 
To run them all, and check that your installation is OK, type

python testall.py -v

If you would like to contribute to PyARTS, which is
definitely encouraged, it is strongly recommended that the above
command is run, and that all tests are successful, before committing
your changes to svn.

Note: currently (19 May 2011), some tests have been disabled because
of significant changes in ARTS since the code was originally written.

Examples
--------

Some example scripts are provided in the examples/ folder.  Most of them
should work as they only depend on data provided in the data/
folder.  Some fail because of changes in ARTS. The testall.py script
described above actually verifies that the examples run without error.

Documentation
-------------

Most modules in the package have reasonably complete docstring
documentation.
This means that in an interactive python session, online help on a
given PyARTS class or function can be obtained by typing ``help(PyARTS_function_or_class)``.
Or, in ipython, ?PyARTS_function_or_class.

The docstring documentation can also be viewed in easily
navigatable html documents by doing the following:

``<wherever your python stuff is>/pydoc.py -p 1234``

and open ``http://localhost:1234`` in your web browser.  

There is a user guide in the doc/ folder of the distribution.


