Program sfplane | Generating plane waves with steering filters. 
[SYNOPSIS]
sfplane < inp.rsf > out.rsf p=0.7 a1=2 b1=1 hyp=n lag=
[PARAMETERS]
int     | a1 | =2 |   | 	filter length 
int     | b1 | =1 |   | 	denominator length 
bool    | hyp | =n |  [y/n] | 	generate hyperbolas 
string  | lag | = |   | 	
float   | p | =0.7 |   | 	plane wave slope 
[DIRECTORY]
user/fomels
