Cactus Code Thorn ParaRand
Authors    : Julian Borrill, John Shalf
CVS info   : $Header$
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Purpose of the thorn: A parallel random number generator.  Generates
consistent/repeatable random number fields regardless of the number
of processors involved in distributed memory runs.  The problem with
random number generation using unix drand() is that if you provide the
same seed for each processor you end up with the same set of random 
numbers for each processor-local domain (which means you get a lattice
of reapeated results when you run your simulation).  However, if you
seed each processor differently, you will get different results 
depending on the number of processors you use.  Ideally you want 
to have repeatable results when you use the same global domain size
regardless of the number of processors you use.  This generator 
accomplishes this by splicing into the correct portion of a well
known random number sequence so that each cell in the computational
domain gets the same part of the overall random number sequence 
regardless of the domain decomposition.

Also includes utilities for different random number distributions 
(spherical,gaussian etc...) suitable for QFT intial data.