SYNOPSIS

PERL PROGRAM NAME:

AUTHOR: Juan Lorenzo (Perl module only)

DATE:

DESCRIPTION:

Version:

USE

NOTES

Examples

SYNOPSIS

SEISMIC UNIX NOTES SUMIGPSPI - Gazdag's phase-shift plus interpolation depth migration

            for zero-offset data, which can handle the lateral         

            velocity variation.                                        



 sumigpspi <infile >outfile vfile= [optional parameters]               

 

 Required Parameters:							

 nz=		number of depth sapmles					

 dz=		depth sampling interval					

 vfile=	name of file containing velocities			

		(Please see Notes below concerning the format of vfile)	



 Optional Parameters:                                                  

 dt=from header(dt) or .004    time sampling interval                  

 dx=from header(d2) or 1.0     midpoint sampling interval              



 tmpdir=        if non-empty, use the value as a directory path        

                prefix for storing temporary files; else if the        

                the CWP_TMPDIR environment variable is set use         

                its value for the path; else use tmpfile()             



 Notes:								

 The input velocity file 'vfile' consists of C-style binary floats.	

 The structure of this file is vfile[iz][ix]. Note that this means that

 the x-direction is the fastest direction instead of z-direction! Such a

 structure is more convenient for the downward continuation type	

 migration algorithm than using z as fastest dimension as in other SU	

 programs. (In C  v[iz][ix] denotes a v(x,z) array, whereas v[ix][iz]	

 denotes a v(z,x) array, the opposite of what Matlab and Fortran	

 programmers may expect.)						



 Because most of the tools in the SU package (such as  unif2, unisam2,	

 and makevel) produce output with the structure vfile[ix][iz], you will

 need to transpose the velocity files created by these programs. You may

 use the SU program 'transp' in SU to transpose such files into the	

 required vfile[iz][ix] structure.					









 Credits: CWP, Baoniu Han, April 20th, 1998



 Trace header fields accessed: ns, dt, delrt, d2

 Trace header fields modified: ns, dt, delrt

User's notes (Juan Lorenzo) untested

CHANGES and their DATES

Import packages

instantiation of packages

Encapsulated hash of private variables

sub Step

collects switches and assembles bash instructions by adding the program name

sub note

collects switches and assembles bash instructions by adding the program name

sub clear

sub dt

sub dx

sub dz

sub nz

sub tmpdir

sub vfile

sub get_max_index

max index = number of input variables -1