README for mapmap
-----------------

mapmap creates maps of aperture mass (M_ap, Schneider 1996). It takes
a FITS_LDAC catalog as input and produces FITS images of aperture mass
maps ("mapmaps") and fits cubes of tomographic peak maps (Hennawi &
Spergel 2005). Optionally it also produces maps of M_ap significance
computed analytically following Eq. 13 of Schirmer et al. (2006,
astro-ph/0607022), maps of -M_ap, mapmaps of the cross-component of
the shear, and mapmaps for a randomized input catalog. For the latter
option the random seed is hardwired to a constant in the program.

The input catalog must at least provide columns with (1) right
ascencion, (2) declination, (3) 1-component of the shear, and (4)
2-component of the shear. Optionally a fifth column can be used to
assign weights to individual shear estimators. Note that although the
positions are expected in right ascencion and declination, the program
expects shear values measured in a Cartesian frame with the values of
the 1-axis increasing from left to right. The table and column names
in the input catalog can be configured via command line options or the
configuration file.

Two filter functions are built in: The polynomial filter of Schneider
et al. (1998, option SCHNEIDER) and the truncated pseudo-NFW filter of
Schirmer et al. (2006, filter SCHIRMER). Different filter functions
can be read from a file (option FILE). The filter radius is set by
assuming a fiducial cluster model and specifying the redshift of the
model cluster and its radius in kpc. 

The size of the output grid is determined by the physical scale at the
redshift of the fiducial model. The default is that one pixel
corresponds to 50 kpc at the model redshift (default 0.3).

mapmap is configured via a SExtractor style configuration file or
command line options. mapmap -c conf_file specifies the location of
the configuration file. If the -c option is not provided mapmap tries
to read mapmap_default.conf in the current working directory. If that
is not found internal default values are used. mapmap -d prints the
internal defaults in the format of the configuration file.



Limitations
-----------

mapmap computes a very simple transformation from equatorial to pixel
coordinates. It will probably fail for very large areas (never tested)
and will definitely fail at the 24h -> 0h transition in right
ascencion and at the poles.


Compilation
-----------

Compilation of mapmap requires the cfitsio library, the GNU Scientific
Library (gsl) with CBLAS extension. Compilation is done with the usual

./configure
make
make install

Efficient use of parallel processing via OpenMP can be enable during
the configure step with the option --enable-openmp.

Some machines (notably massive shared ememory Altix) do not maintain
cache coherence without further instructions by the user. In this case
attaching subprocesses explicitly to a CPU helps. This can be enabled
with the Portable Linux Processor Affinity package included in the
distribution. It is turned off by default because it decreases
performance on most systems but can be enabled with the configuration
switch --enable-plpa.