Program sfsstep2 | 3-D post-stack modeling/migration with extended split step. 
[SYNOPSIS]
sfsstep2 < in.rsf > out.rsf slowness=vel.rsf inv=n verb=n eps=0.01 nt=1 nr=1 padx=0 pady=0 dt=0.004 nw= dw= w0=0.
[PARAMETERS]
float   | dt | =0.004 |   | 	time error 
float   | dw | = |   | 	Frequency sampling (for modeling) 
float   | eps | =0.01 |   | 	stability parameter 
bool    | inv | =n |  [y/n] | 	If y, modeling; if n, migration 
int     | nr | =1 |   | 	maximum number of references 
int     | nt | =1 |   | 	taper size 
int     | nw | = |   | 	Length of frequency axis (for modeling) 
int     | padx | =0 |   | 	cross-line padding 
int     | pady | =0 |   | 	in-line padding 
file    | slowness | = |   | 	auxiliary input file name
bool    | verb | =n |  [y/n] | 	verbosity flag 
float   | w0 | =0. |   | 	Frequency origin (for modeling) 
[DIRECTORY]
system/seismic
