function node_rhs = rhs ( node_num, node_xy )

%*****************************************************************************80
%
%% RHS gives the right-hand side of the differential equation.
%
%  Discussion:
%
%    This routine is set up for the L-shaped region, with exact solution
%    U = X^2 + Y^2.  Hence, the right hand side of the equation is
%    exactly -4.
%
%  Licensing:
%
%    This code is distributed under the GNU LGPL license.
%
%  Modified:
%
%    06 December 2010
%
%  Author:
%
%    John Burkardt
%
%  Parameters:
%
%    Input, integer NODE_NUM, the number of nodes.
%
%    Input, real NODE_XY(2,NODE_NUM),
%    the coordinates of the points.
%
%    Output, real NODE_RHS(NODE_NUM,1), the value of the
%    right hand side function at the points.
%
  node_rhs(1:node_num,1) = -4.0                     ...
                       + node_xy(1,1:node_num).^2 ...
                       + node_xy(2,1:node_num).^2;

  return
end
