Program sfhpef | Multi-dimensional PEF (prediction error filter) estimation on a helix. 
[SYNOPSIS]
sfhpef < in.rsf > filt.rsf maskin=mask.rsf a= center= gap= n= na=0 tol=1.e-6 niter=2*(aa->nh) lag= maskout=
[PARAMETERS]
ints    | a | = |   | 	 [dim]
ints    | center | = |   | 	 [dim]
ints    | gap | = |   | 	 [dim]
string  | lag | = |   | 	output file for filter lags 
string  | maskin | = |   | 	optional input mask file (auxiliary input file name)
string  | maskout | = |   | 	optional output mask file 
ints    | n | = |   | 	 [dim]
int     | na | =0 |   | 	filter size 
int     | niter | =2*(aa->nh) |   | 	number of iterations 
float   | tol | =1.e-6 |   | 	tolerance for filter compression 
[DIRECTORY]
user/gee
