function rule_num = lyness_rule_num ( )

%*****************************************************************************80
%
%% LYNESS_RULE_NUM returns the number of Lyness quadrature rules.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    30 September 2010
%
%  Author:
%
%    John Burkardt
%
%  Reference:
%
%    James Lyness, Dennis Jespersen,
%    Moderate Degree Symmetric Quadrature Rules for the Triangle,
%    Journal of the Institute of Mathematics and its Applications,
%    Volume 15, Number 1, February 1975, pages 19-32.
%
%  Parameters:
%
%    Output, integer RULE_NUM, the number of rules.
%
  rule_num = 21;

  return
end
