Program sfrays2a | Ray tracing in VTI media by a Runge-Kutta integrator.
[SYNOPSIS]
sfrays2a < vz.rsf > rays.rsf shotfile=shots.rsf anglefile=angles.rsf vel=y order=4 nt= dt= verb=y escvar=n zshot=0. yshot=o[1] + 0.5*(n[1]-1)*d[1] nr= a0=0. amax=360. vx= eta= > rays.rsf
[COMMENTS]
Rays can be plotted with sfplotrays.

[PARAMETERS]
float   | a0 | =0. |   | 	minimum angle (if no anglefile) 
float   | amax | =360. |   | 	maximum angle (if no anglefile) 
string  | anglefile | = |   | 	file with initial angles (auxiliary input file name)
float   | dt | = |   | 	Sampling in time 
bool    | escvar | =n |  [y/n] | 	If y - output escape values, n - trajectories 
string  | eta | = |   | 	eta parameter 
int     | nr | = |   | 	number of angles (if no anglefile) 
int     | nt | = |   | 	Number of time steps 
int     | order | =4 |   | 	Interpolation order 
string  | shotfile | = |   | 	file with shot locations (auxiliary input file name)
bool    | vel | =y |  [y/n] | 	If y, input is velocity; if n, slowness 
bool    | verb | =y |  [y/n] | 	Verbosity flag 
string  | vx | = |   | 	horizontal velocity or slowness 
float   | yshot | =o[1] + 0.5*(n[1]-1)*d[1] |   | 	
float   | zshot | =0. |   | 	shot coordinates (if no shotfile) 
[DIRECTORY]
system/seismic
