% -*- texinfo -*-
% @deftypefn {Function File} {@var{retval} =} is_abcd (@var{a}, @var{b}, @var{c}, @var{d})
% Returns @var{retval} = 1 if the dimensions of @var{a}, @var{b},
% @var{c}, @var{d} are compatible, otherwise @var{retval} = 0 with an
% appropriate diagnostic message printed to the screen. The matrices
% @var{b}, @var{c}, or @var{d} may be omitted.
% @seealso{abcddim}
% @end deftypefn