Program sfarrival | Multiple-arrival interpolation from down-marching. 
[SYNOPSIS]
sfarrival < in.rsf place=place.rsf > out.rsf depth=depth.rsf sx=0. nw=3
[PARAMETERS]
string  | depth | = |   | 	auxiliary input file name
int     | nw | =3 |   | 	interpolation accuracy 
file    | place | = |   | 	auxiliary input file name
float   | sx | =0. |   | 	source x position 
[DIRECTORY]
user/fomels
