BEAM_PATCH

    The dirty beam patch to be used for  the  minor  cycles  in  CLARK  and  MRC
    method.  It should be large enough to avoid doing too many major cycles, but
    has  practically  no influence on the result.  This size should be specified
    in pixel units.  Reasonable values are between N/8 and N/4, where N  is  the
    number  of  map  pixels in the same dimension.  If set to N, the CLARK algo-
    rithm becomes identical to the HOGBOM algorithm.