Synopsis
		sfdivn < fnum.rsf den=fden.rsf > frat.rsf niter=100 verb=y eps=0.0f rect#=(1,1,...)

December 2015 program of the month:
http://ahay.org/blog/2015/12/22/program-of-the-month-sfdivn/

Parameters
		file den= auxiliary input file name   float eps=0.0f regularization   int niter=100 number of iterations   int rect#=(1,1,...) smoothing radius on #-th axis   bool verb=y [y/n] verbosity