Synopsis
		sfeikfswp < vel.rsf > time.rsf vel=y niter=2 zshot=0. yshot=o2 + 0.5*(n2-1)*d2 xshot=o3 + 0.5*(n3-1)*d3 shotfile= horizon=

Parameters
		string horizon= File with a reflection interface   int niter=2 number of sweeping iterations   string shotfile= File with shot locations (n2=number of shots, n1=3)   bool vel=y [y/n] if y, the input is velocity; n - slowness   float xshot=o3 + 0.5*(n3-1)*d3   float yshot=o2 + 0.5*(n2-1)*d2   float zshot=0. Shot location (used if no shotfile)