Help for QSWP2005

PURPOSE:
"qswp2005" accepts an input dataset that has been fourier transformed
and requires the quadrants to be swapped.  It also has the option to
reverse the swap with "REVERSE" keyword.

EXECUTION:

	qswp2005 INP OUT OP

where:  INP  is the input FFT or matrix of FFTs.
	OUT  is the output file.
        OP   is a keyword that tells whether the dataset has
             already been swapped or not.
OPERATION:
"qswp2005" performs the operation shown in the following diagrams.
The letters A,B,C,D refer to fft quadrants.
+-------+-------+     +-------+------- |DC     |       |     |       |       |
|       |       |     |       |       |
|   A   |   B   |     |   D   |   C   |
|       |       |     |       |       |
+-------+-------+ --> +-------+------- |       |       |     |       |DC     |
|       |       |     |       |       |
|   C   |   D   |     |   B   |   A   |
|       |       |     |       |       |
+-------+-------+     +-------+-------   INPUT FFT           DEFAULT OPERATION

WARNING:  Program "qswp2005" perfroms its operation by reading each
FFT entirely into memory.  If its size is large, then it may run very
slowly!

EXAMPLES

	qswp2005 INP=A OUT=B OP=FORWARD

        This command will cause the program to take in the input
        dataset A swap the quadrants and output the result into
        B.  The FORWARD tells the program that the quadrants in
        the input dataset has not been swapped yet.

	qswp2005 INP=A OUT=B OP=REVERSE

        This command will cause the program to take in the input
        dataset A swap the quadrants and output the result into
        B.  The REVERSE tells the program that the quadrants in
        the input dataset has been swapped previously.

Original Programmer    :  P. Kim,  13 Nov 2007
Delivered into vdev    :  P. Kim,  29 Nov 2007
Revisions:
Thu Jan  3 2008 wlb switched to USES_ANSI_C AND LIB_CARTO; misc cleanup  
2022-08-10 B. Crocco afids to opensource (untested)

PARAMETERS: