Synopsis
		sfttieikonal < vzf.rsf > time.rsf niter=4 nfpi=3 zshot=0. yshot=o2 + 0.5*(n2-1)*d2 epsilon= delta= theta= shotfile=

Parameters
		string delta=   string epsilon=   int nfpi=3 number of fixed-point iterations   int niter=4 number of sweeping iterations   string shotfile= File with shot locations (n2=number of shots, n1=3)   string theta=   float yshot=o2 + 0.5*(n2-1)*d2   float zshot=0. Shot location (used if no shotfile)