Program:      SHUFFLE

Purpose:      The programme shuffles profiles in a set so that they are
              aligned on positions taken from another set.

Category:     ANALYSIS, COMBINATION, MANIPULATION

File:         shuffle.c

Author:       K.G. Begeman

Keywords:

   INSET=     Set and subsets of data to be shuffled. Maximum number
              of subsets is 128.

   CSET=      Set and subset which contains the positions of the
              profile centres. CSET could be a velocify field created by
              MOMENTS or GAUFIT.

   NMAX=      Number of output subsets to one side of the profile centres.
              The total number of output subsets is 2*NMAX+1. Maximum
              value for NMAX is 128.

   CDELT=     Grid separation in units of the output subsets. A default
              is calculated from the input subsets. CDELT must be positive.

   OUTSET=    Set (and subsets) where the shuffled profiles are to be
              stored. The number of output subsets is 2*NMAX+1.

Description:  With the input data cube and one input velocity field,
              SHUFFLE shifts all spectra such that their new origins
              correspond to the velocities in the velocity field. These
              origins are set to the coordinate 0 in the output set.
              The interpolation required along the spectral axis is
              done with a simple linear interpolation.

Example:      <USER> SHUFFLE INSET=n4214 freq-ohel
              Set n4214 has 3 axes
              RA-NCP             from  -127 to   128
              DEC-NCP            from  -127 to   128
              FREQ-OHEL          from     1 to    63
              <USER> SHUFFLE CSET=n4214vel param 1
              Set n4214vfield has 3 axes
              RA-NCP             from  -127 to   128
              DEC-NCP            from  -127 to   128
              PARAM-GAUFIT       from     1 to     3
              <USER> SHUFFLE NMAX=32
              <USER> SHUFFLE CDELT=8
              <USER> SHUFFLE OUTSET=shuffle
              Set shuffle has 3 axes
              RA-NCP             from  -127 to   128
              DEC-NCP            from  -127 to   128
              VELO               from   -32 to    32
              <STATUS>  SHUFFLE   +++ FINISHED +++

Notes:        In general the axes names of the output set will be the
              same as the ais names of the input set, except for
              frequency axis with velocity information. In these cases
              the axis name will be converted to VELO.

Updates:      Jul 15, 1992: KGB, Document created.
              Mar 09, 2000: JMH, increased NMAX to 128