Download
========
A tarball containing acstools, this documentation, and test data is available
at http://stsdas.stsci.edu/download/acstools_nvidia/acstools_nvidia.tar.gz.

.. _installation_label:

Installation
============

Requirements:

* `Python <http://www.python.org>`_ 2.5-2.7
* `numpy <http://numpy.scipy.org>`_
* `pyfits <http://www.stsci.edu/resources/software_hardware/pyfits>`_

With the above requirements installed run the following commands at the
command line::

  cd acstools
  python setup.py build
  python setup.py install
  
If all of the above steps run correctly acstools should now be installed, 
which you can test by typing ``import acstools`` at the Python interactive
prompt.

.. _run_label:

Running CTE Correction
======================

Running the CTE correction is simple using the ``acstools.PixCteCorr.YCte``
function. An example from the Python interactive prompt::

  >>> import acstools.PixCteCorr as pcc
  >>> pcc.YCte('jb1f89eoq_flt.fits')
  
This will make an output file called ``jb1f89eoq_cte.fits``. The output file
name may also be specified::

  >>> import acstools.PixCteCorr as pcc
  >>> pcc.YCte('jb1f89eoq_flt.fits','corrected_output.fits')
  
Use the Python ``help`` function to see more information on ``YCte``::

  >>> import acstools.PixCteCorr as pcc
  >>> help(pcc.YCte)
  
As a convenience we have included scripts called ``run_correction.py`` in each
of the data directories that can be used to run the CTE correction. Run them
by typing ``python run_correction.py`` at the command line.
  
Comparing Results
=================

Installed along with acstools is a script called ``fitsdiff``, which is useful
for comparing FITS files::

  fitsdiff -c '*' -k '*' jb1f89eoq_cte.fits jb1f89eoq_cte_ref.fits

   fitsdiff:  1.5 (28 Feb 2011)
   file1 = jb1f89eoq_cte.fits
   file2 = jb1f89eoq_cte_ref.fits
   Keyword(s) not to be compared:  ['*']
   Keyword(s) whose comments not to be compared:  ['*']
   Column(s) not to be compared:  ['']
   Maximum number of different pixels to be reported:  10
   Data comparison level:  0.0

  Primary HDU:
    Inconsistent occurrence of keyword          jb1f89eoq_cte.fits has 58, jb1f89eoq_cte_ref.fits has 57
    Inconsistent occurrence of keyword HISTORY  jb1f89eoq_cte.fits has 34, jb1f89eoq_cte_ref.fits has 35
  Input files have naught dimensions

  IMAGE Extension 1 HDU:
      There are 0 different data points.

  IMAGE Extension 2 HDU:
      There are 0 different data points.

  IMAGE Extension 3 HDU:
      There are 0 different data points.

  IMAGE Extension 4 HDU:
      There are 0 different data points.

  IMAGE Extension 5 HDU:
      There are 0 different data points.

  IMAGE Extension 6 HDU:
      There are 0 different data points.
      
The ``-c '*' -k '*'`` options tell ``fitsdiff`` not to compare header keywords
or comments since we are just interested in whether the data match. Type
``fitsdiff -h`` at the command line to see the full help text. In this case
we are also not interested in the results about the "Primary HDU". Rather we
are making sure that for each "IMAGE Extension # HDU" there are 0 reported
differences.

For convenience we have included scripts called ``run_comparison.py`` in each
of the data directories that will run fitsdiff as in the above example. Run them
by typing ``python run_comparison.py`` at the command line.