next up previous contents
Next: GENDOCS - An Instant Up: SUFIND - Find SU Previous: SUFIND - Find SU   Contents

Getting information about SU programs

A more specific example would be to use sufind to look for dip moveout (DMO) programs:

% sufind dmo

 SUDMOFK - DMO via F-K domain (log-stretch) method for common-offset gathers

 sudmofk <stdin >stdout cdpmin= cdpmax= dxcdp= noffmix= [...]           


 SUDMOTX - DMO via T-X domain (Kirchhoff) method for common-offset gathers

 sudmotx <stdin >stdout cdpmin= cdpmax= dxcdp= noffmix= [optional parms]

 SUDMOVZ - DMO for V(Z) media for common-offset gathers

 sudmovz <stdin >stdout cdpmin= cdpmax= dxcdp= noffmix= [...]     

 SUFDMOD2 - Finite-Difference MODeling (2nd order) for acoustic wave equation

 sufdmod2 <vfile >wfile nx= nz= tmax= xs= zs= [optional parameters]     


 SUSTOLT - Stolt migration for stacked data or common-offset gathers    

 sustolt <stdin >stdout cdpmin= cdpmax= dxcdp= noffmix= [...]
The last two ``hits'' are spurious, but we see that three DMO programs have been found.

Now use the self-doc facility to get more information about sudmofk:

% sudmofk
                                                                        
 SUDMOFK - DMO via F-K domain (log-stretch) method for common-offset gathers
                                                                        
 sudmofk <stdin >stdout cdpmin= cdpmax= dxcdp= noffmix= [...]           
                                                                        
 Required Parameters:                                                   
 cdpmin                  minimum cdp (integer number) for which to apply DMO
 cdpmax                  maximum cdp (integer number) for which to apply DMO
 dxcdp                   distance between adjacent cdp bins (m) 
 noffmix                 number of offsets to mix (see notes)           
                                                                        
 Optional Parameters:                                                   
 tdmo=0.0                times corresponding to rms velocities in vdmo (s)
 vdmo=1500.0             rms velocities corresponding to times in tdmo (m/s)
 sdmo=1.0                DMO stretch factor; try 0.6 for typical v(z)   
 fmax=0.5/dt             maximum frequency in input traces (Hz) 
 verbose=0               =1 for diagnostic print                        
                                                                        
 Notes:                                                         
 Input traces should be sorted into common-offset gathers.  One common- 
 offset gather ends and another begins when the offset field of the trace
 headers changes.                                                       
                                                                        
 The cdp field of the input trace headers must be the cdp bin NUMBER, NOT
 the cdp location expressed in units of meters or feet.         
                                                                        
 The number of offsets to mix (noffmix) should typically equal the ratio of
 the shotpoint spacing to the cdp spacing.  This choice ensures that every
 cdp will be represented in each offset mix.  Traces in each mix will   
 contribute through DMO to other traces in adjacent cdps within that mix.
                                                                        
 The tdmo and vdmo arrays specify a velocity function of time that is   
 used to implement a first-order correction for depth-variable velocity.
 The times in tdmo must be monotonically increasing.                    
                                                                        
 For each offset, the minimum time at which a non-zero sample exists is 
 used to determine a mute time.  Output samples for times earlier than this
 mute time will be zeroed.  Computation time may be significantly reduced
 if the input traces are zeroed (muted) for early times at large offsets.
                                                                        
 Trace header fields accessed:  ns, dt, delrt, offset, cdp.
By using sufind in conjunction with the selfdoc feature (or sudoc), and choosing smart strings to search on, it is possible to find a great deal of detailed information about SU's facilities.



John Stockwell 2007-04-10