Synopsis
		sffourbreg2 < in.rsf > out.rsf mask=mask.rsf res=res.rsf ref=ref.rsf niter=20 verb=n error=n perc=99. fact=0.5

Parameters
		bool error=n [y/n] error verbosity flag   float fact=0.5 factor for soft-thresholding   string mask= auxiliary input file name   int niter=20 number of iterations   float perc=99. percentage for soft-thresholding   file ref= auxiliary input file name   string res= auxiliary output file name   bool verb=n [y/n] verbosity flag