%N cnvlinif %F $MIR/src/subs/cnvl.for
%D Ready a beam, from a file, for a convolution operation.
%P rjs
%: convolution, fft
%B
      subroutine CnvlIniF(handle,lu,n1,n2,ic,jc,param,flags)

      ptrdiff handle
      integer lu,n1,n2,ic,jc
      character flags*(*)
      real param

  This routine readys a beam pattern for a series of convolution
  operations.  In particular, it reads a beam from a Miriad image file,
  performs an FFT on it, and stores the result in memory.  It returns a
  handle which points to the structure containing the needed
  information.

  Input:
    lu         Handle of the beam file.
    n1,n2      Size of the beam. Need not be powers of two.
    ic,jc      Central pixel of the beam.
    param      A real parameter value. Its use is determined by the
               "flags" argument.
    flags      Extra processing flags, each character indicating
               another processing option.  Possible values are:
                 's'   Assume beam is symmetric.
                 'p'   Param is the value of a Prussian hat to add to
                       the beam.
                 'd'   Perform deconvolution (rather than convolution).
                       Param is the nominal error in the beam.
                 'e'   Double the size of the beam (through zero
                       padding) to avoid various edge effects.
  Output:
    handle     Handle to the transformed beam.
