Program sffwidir | Update the conjugate direction in full waveform inversion 
[SYNOPSIS]
sffwidir < in.rsf > out.rsf grad0=grad0.rsf grad1=grad1.rsf beta=beta.rsf option=
[PARAMETERS]
string  | beta | = |   | 	auxiliary output file name
file    | grad0 | = |   | 	auxiliary input file name
file    | grad1 | = |   | 	auxiliary input file name
string  | option | = |   | 	CG update parameter (Polak, Fletcher-Reeves, Fletcher, Dai-Yuan) 
[DIRECTORY]
user/zhiguang
