readme

Readme for FLATlib v0.7
--------------------------

FLATlib is a Fortran90 library for performing fast convolution of
theoretical spectra with the instrumental response functions of the
Fermi Large Area Telescope (LAT).  This release is probably the final beta
version of the library, for use within and outside the Fermi collaboration.
It contains P6_v1, P6_v3, P7_v1 and P7_V6 IRFs.  This version is minimally
documented; later releases might contain more documentation.

To use flatlib, copy the contents of the tarball to whatever directory
you like, retaining the directory structure.  Make sure you have the cfitsio, 
fftw3 and m libraries installed and accessible in your default libray paths.  
Modify the makefile in the root directory to suit your compiler preferences.  
Compile the library, utilities and test program by just typing 'make' in the 
flatlib root directory.

In general, the IRFs need to be averaged before any fast convolutions can be 
done.  This can be done in advance using 
./flataverage <IRF folder name>
in the data directory.  If this has not been done already, it will be done 
automatically anyway for the chosen IRFs when flatConvolve_fast_init is 
called to set up the convolution.  The averaging may take a very long time
to run, depending upon your computer speed and whether you modified any of
the options in src/flatCommon.f90.

Once these are done, you can run the test program by typing
./flattest
and checking that there are no errors in the output.  Refer to 
src/flatTest.f90 for an example of how to call the library from your
own programs.

Note that the compiled library which you will need to link to is 
lib/libflatlib.a; the other libraries in lib/ are just temporaries
and are not required to be linked to by end users.

Pat Scott  	July 7 2009
Updated 	Feb 21 2011
		Oct 20 2011
		Apr 12 2012
                Mar 12 2013