SUIMP2D - generate shot records for a line scatterer embedded in three dimensions using the Born integral equation

 suimp2d [optional parameters] >stdout               

 Optional parameters                           
      nshot=1           number of shots              
      nrec=1            number of receivers          
      c=5000            speed                  
      dt=.004           sampling rate                
      nt=256            number of samples      
      x0=1000           point scatterer location     
      z0=1000           point scatterer location     
      sxmin=0           first shot location          
      szmin=0           first shot location          
      gxmin=0           first receiver location      
      gzmin=0           first receiver location      
      dsx=100           x-step in shot location      
      dsz=0      z-step in shot location      
      dgx=100           x-step in receiver location  
      dgz=0       z-step in receiver location  

 Example:                                
      suimp2d nrec=32 | sufilter | supswigp | ...    


 Credits:
      CWP: Norm Bleistein, Jack K. Cohen


 Theory: Use the 3D Born integral equation (e.g., Geophysics,
 v51, n8, p1554(7)). Use 2-D delta function for alpha and do
 remaining y-integral by stationary phase.

 Note: Setting a 2D offset in a single offset field beats the
       hell out of us.  We did _something_.

 Trace header fields set: ns, dt, tracl, tracr, fldr, sx, selev,
                          gx, gelev, offset