This README describes the Python version of fitgal, refered to as fitgal.py

The fitgal tar file will contain the following 9 files

0. This README file
1. fitgal.py: The main fitgal program
2. fitgalfunc.py: A set of functions and subroutines needed by fitgal.py
3. config.py: The fitgal configuration file. You control fitgal's
fitting behavior mostly by modifying this file. 

For testing purposes, I have also provided:
4. test1.fits: A FITS file with a sample image taken from SDSS r-band data.
5. gauss25.fits: The PSF image correspoding to the galaxy data above.
6. mask.fits: A mask file that can be used in conjunction with test1.fits
7. runfitgal: a single line script to call the fitgal.py program
8. matplotlibrc: a configuration file for matplotlib plotting library

Preparation
-----------
PLEASE SKIP THIS PREPARATION STEP TILL SARAH INSTALLS MATPLOTLIB
The matplotlibrc file needs to be moved to the right location. To do that:

mkdir ~/.matplotlib
mv matplotlibrc ~/.matplotlib

Follow fitting progress on the web
----------------------------------

Every 100 iterations, the program writes a HTML file called fitgal.html.
To follow the progress of your fitting on the web do the following
1. Unpack the fitgal.tar file in your web directory (or a sub-directory) 
eg. I unpacked mine in /usr1/yogesh/public_html/fitgal
2. Set the webdir variable in config.py to point to this directory
eg. For the directory above, I used:
webdir='http://meghnad.iucaa.ernet.in/~yogesh/fitgal/'
Note: trailing slash is required!
3. Run the code (see next section)
4. Point your browser to the fitgal.html file at that URL
eg. I need to point mine to:
http://meghnad.iucaa.ernet.in/~yogesh/fitgal/fitgal.html
The page refreshes automatically. Enjoy! 

Running the code
----------------

To run fitgal.py simply type,

./runfitgal

at the shell prompt. The current best fit values are printed to
STDOUT after every 50 iterations.

The order of the parameters is:
'i0b', 're', 'eb', 'n', 'i0d', 'rd', 'ed', 'point', 'bpa','dpa', 'background'
 
Tip: Fitting should take about 157 seconds on aten without graphical
output, somewhat longer with graphics outputs.

After the fitting is complete, the following output files are generated.

1. model.fits: FITS file with the best fit model convolved with the PSF
2. bulge.fits: FITS file with the best fit bulge convolved with the PSF
3. disk.fits : FITS file with the best fit disk convolved with the PSF
4. residual.fits: (real-model)/real FITS file.
5. fitgal.csv: the best fit parameters in CSV format.
6. fitgal.png: PNG file of the final iteration graphical plot
7. fitgal.ps: Postscipt file of the final iteration graphical plot

Note: fitgal.png and fitgal.ps are only produced if matplotlib is installed.

To run the script on your own galaxy image, you need to modify the runfitgal
file. 

You will need to supply a galaxy image (fits cutout), PSF image (with
PSF properly centered) and the xcenter and ycenter of the galaxy and
what components you will fit. 

./fitgal.py test1.fits gauss25.fits 26.74 27.53 1 1 1

The  seven arguments are:
1. test1.fits: The galaxy FITS image
2. gauss25.fits: The PSF image
3. 26.74: X-center of galaxy
4. 27.53: Y-center of galaxy
5. 1: Fit bulge, use 0 here for don't fit bulge
6. 1: Fit disk, use 0 here for don't fit disk
7. 1: Fit point, use 0 here for don't fit point

You can also modify the parameter initial values, ranges and
whether the parameter should be held fixed. You will need to change
the config.py file to do this. The code is commented to aid you.

If you want to learn more
-------------------------

You may wish to read the code. Start with the file fitgal.py to follow
the rather straightforward logic. For the details, read
fitgalfunc.py. config.py contains all the user configurable
parameters. Reading Python is easy, even if you don't know the
language. Remember: in python, identation is the only way to define
the beginning and end of blocks.