%N cnvlco %F $MIR/src/subs/cnvl.for
%D Correlate two beam patterns.
%P rjs
%: convolution, fft
%B
      subroutine CnvlCo(handle1,handle2,flags)

      ptrdiff handle1,handle2
      character flags*(*)

  Convolve or Correlate two beam patterns. The result is overwrites
  handle1.

  In the transform domain, this is equivalent to

    Beam1 = Beam1 * conjg(Beam2)       (correlation)
     or
    Beam1 = Beam1 * Beam2              (convolution).

  Input:
    handle1    The beam handle of the input/output beam pattern.
    handle2    The beam handle of the other input beam.
    flags      Extra processing flags, each character indicating
               another processing option.  Possible values are:
                 'x'   Perform correlation. The default is to perform
                       convolution.
