Synopsis
		sfstackn < in.rsf > out.rsf min=minin.rsf max=maxin.rsf mean=y thres=0.

Parameters
		string max= file determining up to which value to stack (auxiliary input file name)   bool mean=y [y/n] if n, sum; if y, average   string min= file determining from which value to stack (auxiliary input file name)   float thres=0. threshold (percentage of maxabs)

Used In
		SWAG          itime/oz2 itime/oz6 itime/syn