Synopsis
		sfbigmpistack nx= ny= nz= debug=n verb=n dx= dy= dz= oz= oy= ox= nf= jf= of= prefix= shots= oname=

Assumes that files are commonly named sequentially, e.g.:

File001.rsf
File002.rsf
File003.rsf ...
FileN.rsf

Such that all files can be represented as a prefix, which
is a printf like statement that will be evaluated for all
files to be included in a range.

For the above example the prefix would be:

prefix="File%03d.rsf"

The nf, jf, and of parameters specify a range of numbers to evaluate the
prefix for, giving the program filenames to be used for summing
together. For example:

nf=10,of=0,jf=1 --> (0,1,2,3,4,5,6,7,8,9,10)
nf=10,of=5,jf=2 --> (5,7,9,11,13,15,17,19,21,23)

If there are more files than processes, then this program will subdivide
the files onto various processes, and run multiple rounds until
everything is done.

These must be 3D arrays (or 2D ,but with three dimensions), arrays must be
X-Y-Z
a1-a2-a3

Parameters
		bool debug=n [y/n]   float dx=   float dy=   float dz=   int jf= delta between files   int nf= number of files to stack   int nx= origin of files   int ny= origin of files   int nz= origin of files   int of= origin of files   string oname= name of output file   float ox=   float oy=   float oz=   string prefix= printf like prefix   string shots= name of shot file   bool verb=n [y/n]