Synopsis
		sfisaac1 < refl.rsf > ttime.rsf xrefl=xrefl.rsf ns=nr ns2=nr ds=dr ds2=dr s0=r0 s02=r0 type=1 order=4 velocity=2.0 tol=1/(1000000*velocity) break=n

Parameters
		bool break=n [y/n] Go beyond zero or not   float ds=dr source sampling for midpoint   float ds2=dr source sampling for offset   int ns=nr number of sources for midpoint   int ns2=nr number of sources for offset   int order=4 Interpolation order if choose to use sf_eno   float s0=r0 origin for midpoint   float s02=r0 origin for offset   float tol=1/(1000000*velocity) Assign a default value for tolerance   int type=1 Interpolation type 0=sf_eno and 1=central finite difference   float velocity=2.0 Assign velocity km/s   file xrefl= auxiliary output file name