Program sfmpifwigrad | Calculate acoustic FWI gradient with the prepared adjoint source 
[SYNOPSIS]
sfmpifwigrad Fvel=Fv.rsf Fwavelet=Fw.rsf Fadj=Fadj.rsf Fgrad=Fgrad.rsf Fwfl1=Fwfl1.rsf Fwfl2=Fwfl2.rsf ns= ds= s0= sz=5 nr=nx dr=dx r0=x0 rz=5 frectx=2 frectz=2 nb=100 coef=0.002
[PARAMETERS]
file    | Fadj | = |   | 	auxiliary input file name
file    | Fgrad | = |   | 	auxiliary output file name
file    | Fvel | = |   | 	auxiliary input file name
file    | Fwavelet | = |   | 	auxiliary input file name
file    | Fwfl1 | = |   | 	auxiliary output file name
file    | Fwfl2 | = |   | 	auxiliary output file name
float   | coef | =0.002 |   | 	absorbing boundary coefficient 
float   | dr | =dx |   | 	receiver interval 
float   | ds | = |   | 	shot interval 
int     | frectx | =2 |   | 	source smoothing in x 
int     | frectz | =2 |   | 	source smoothing in z 
int     | nb | =100 |   | 	boundary width 
int     | nr | =nx |   | 	number of receiver 
int     | ns | = |   | 	shot number 
float   | r0 | =x0 |   | 	receiver origin 
int     | rz | =5 |   | 	receiver depth 
float   | s0 | = |   | 	shot origin 
int     | sz | =5 |   | 	source depth 
[DIRECTORY]
user/zhiguang
