function quad_error = monomial_quadrature_tri ( dim_num, expon, point_num, x, weight )

%% MONOMIAL_QUADRATURE_TRI applies a quadrature rule to a monomial in a triangle.
%
%  Modified:
%
%    03 July 2007
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, integer DIM_NUM, the spatial dimension.
%
%    Input, integer EXPON(DIM_NUM), the exponents.
%
%    Input, integer POINT_NUM, the number of points in the rule.
%
%    Input, real X(DIM_NUM,POINT_NUM), the quadrature points.
%
%    Input, real WEIGHT(POINT_NUM), the quadrature weights.
%
%    Output, real QUAD_ERROR, the quadrature error.
%

%
%  Get the exact value of the integral of the unscaled monomial.
%
  scale = monomial_int_tri_unit ( dim_num, expon );
%
%  Evaluate the monomial at the quadrature points.
%
  value = monomial_value ( dim_num, point_num, x, expon );
%
%  Compute the weighted sum and divide by the exact value.
%
  area = 0.5;
  quad = area * ( weight * transpose ( value ) ) / scale;
%
%  Error:
%
  exact = 1.0;
  quad_error = abs ( quad - exact );