crisThickMaps package

	author: bruce sears
	released: 3-19-97

	This package is used for determining the absolute thickness
	of a cris detector given the stack location of the cris detector
	and a point (x, y) on the detector.  The stack location is a
	string of the form "T6-1B", "T2C", "T7-2A", etc.  See the comments
	in parseStackDetectorID.c for more details.

	There are some mid-sized databases intertwined with these
	routines.  For speed in running, these databases are not read
	from the text files included in this package.  Instead,
	pre-compiler scripts are run which read the text databases
	and embed them into C arrays inside the C code prior to
	compilation.  For this reason, some of the .c files are
	quite long.  All of the c code will be near the end of these
	files (after the arrays.)  You do not need to worry about
	this process, as the .c files have already been generated
	and are ready to be compiled here.  But if you are curious or
	need to understand the pre-process method, see the section
	below called PRE-COMPILATION PROCESSING DETAILS.  If you will
	be modifying any of the code in this package, you should
	probably read it.  Most users will only be interested in
	the .c files here.

	PRE-COMPILATION PROCESSING DETAILS:
	Some of the .c files in this package have a .src and a
	generate script involved with them.  The .src file has
	all of the C code in it with the exception of having
	tags where constants and arrays will be placed.  The
	scripts (written in perl) parse all the databases in the
	package and replace the tags in the .src file with values
	and arrays in order to create the .c file.  For this reason,
	if you are planning on fooling with any of this, be aware
	that such .c files are automatically generated from the
	script and the contents of the .src file.  Edits of the C code
	would be done in the .src file, then the generate script would
	be run, producing the .c file.


version 2.00:
	ported to c from idl (version 1.xx)

	some declarations (from the header file):

	    struct dblAndInt { double dbl; int i; };
		this struct is merely an easy way to return a double and an int

	    struct dblAndInt getCrisThickness(char* stackDetectorID,
							double x, double y);

	usage:
	    struct dblAndInt thicknessAndExtrapCount;
	    double thickness;
	    int extrapCount;

	    thicknessAndExtrapCount = getCrisThickness(stackDetectorID, x, y);
	    thickness = thicknessAndExtrapCount.dbl;
	    extrapCount = thicknessAndExtrapCount.i;


		stackDetectorID = detector's location in the cris stacks.  It
			is a string of format "T2A", or "T6-2D" for telescope
			partitions with multiple detectors.
		x, y = "bs-coordinates" location on said detector.  bs-coords
			are defined at
			http://www.srl.caltech.edu/ACE/forum/topics/ACE
		thickness = thickness at (x, y) in microns 
		extrapCount = the value of thickness at (x, y)
			is interpolated between the 4 nodes
			at the corners of 3 mm x 3 mm pixels.
			The nodes correspond to the points which
			were measured by the MSU particle maps
			of the cris detectors.  At the edges of the
			detector, the thickness has been extrapolated
			to the nodes outside of the actual measurments.
			extrapCount will usually return as 0, but near
			the edges of the detector may be from 1 to 3.
			if extrapCount = 4, the point you are looking
			at is probably not physically on the detector
			even though get_cris_thickness may return a
			thickness value using 4 extrapolated nodes.
			(integer)

			IMPORTANT: Version 2.00 returns 0 thicknesses
			for all extrapolated values.  This will be fixed
			in the next version.

	compiling:
	    edit the Makefile in the main directory as directed therein, and
	    then type "make".  if you are not using a unix system, then you
	    will need to get help from your local systems people.  make may
	    be available on other systems as well.  it is merely a nice utility
	    for compiling and linking sets of code.  please contact me if there
	    are any questions or problems here.  the end result of this make
	    is a library of compiled object files, libCrisThickMaps.a

	example compilation and use:
	    in the directory USAGE_TEST, there is a sample program which calls
	    getCrisThickness.  there is also another Makefile there which
	    illustrates how to link in libCrisThickMaps.a.