Program sfofd2_25 | 2-D Fourth-order Optimized Finite-difference wave extrapolation 
[SYNOPSIS]
sfofd2_25 > out.rsf vel=vel.rsf < source.rsf G=G.rsf s1=files1.rsf s2=files2.rsf dt= nt= isx= isz=
[PARAMETERS]
file    | G | = |   | 	auxiliary input file name
float   | dt | = |   | 	
int     | isx | = |   | 	
int     | isz | = |   | 	
int     | nt | = |   | 	
file    | s1 | = |   | 	auxiliary input file name
file    | s2 | = |   | 	auxiliary input file name
file    | vel | = |   | 	auxiliary input file name
[DIRECTORY]
user/songxl
