Synopsis
		sfdrayinte < in.rsf > out.rsf deriv=deriv.rsf t0=0. shift=1. source=o[1]+(n[1]-1)/2*d[1]

Parameters
		string deriv= auxiliary input file name   float shift=1. complex source shift   float source=o[1]+(n[1]-1)/2*d[1] source location   float t0=0. time origin at source