Synopsis
		sfisaac0 < refl.rsf > ttime.rsf xrefl=xrefl.rsf ns=nr ds=dr s0=r0 order=3 velocity=2.0 tol=0.0001/velocity

Parameters
		float ds=dr source sampling   int ns=nr Number of sources   int order=3 interpolation order   float s0=r0 source origin   float tol=0.0001/velocity assign a default value for tolerance   float velocity=2.0 assign velocity km/s   file xrefl= auxiliary output file name