function p21_demo ( iteration_max, h ) %*****************************************************************************80 % %% P21_DEMO runs the 2D demo problem #21, with mesh size H. % % Licensing: % % This code is distributed under the GNU LGPL license. % % Modified: % % 26 June 2013 % % Author: % % John Burkardt % % Reference: % % Per-Olof Persson, Gilbert Strang, % A Simple Mesh Generator in MATLAB, % SIAM Review, % Volume 46, Number 2, June 2004, pages 329-345. % % Parameters: % % Input, integer ITERATION_MAX, the maximum number of iterations. % % Input, real H, the mesh spacing parameter. % addpath ( '../distmesh' ) if ( nargin < 1 ) iteration_max = 200; fprintf ( 1, '\n' ); fprintf ( 1, 'P21_DEMO - Note:\n' ); fprintf ( 1, ' No value of ITERATION_MAX was supplied.\n' ); fprintf ( 1, ' The default value ITERATION_MAX = %d will be used.\n', ... iteration_max ); end if ( nargin < 2 ) h = 0.1; fprintf ( 1, '\n' ); fprintf ( 1, 'P21_DEMO - Note:\n' ); fprintf ( 1, ' No value of H was supplied.\n' ); fprintf ( 1, ' The default value H = %g will be used.\n', h ); end % % Put the random number generator into a fixed initial state. % rand ( 'state', 111 ); % % Set the rendering method for the current figure to Z-buffering. % set ( gcf, 'rend', 'z' ); fprintf ( 1, '\n' ); fprintf ( 1, 'Problem 21:\n' ); fprintf ( 1, ' Zhu Wang''s 3x3 square with a quarter-round bite.\n' ); fprintf ( 1, ' H = %f\n', h ); fd = @p21_fd; fh = @p21_fh; box = [ -1.2, -1.2; 3.0, 3.0 ]; fixed = []; [ p, t ] = distmesh_2d ( fd, fh, h, box, iteration_max, fixed ); post_2d ( p, t, fh ) % % Write a PostScript image of the triangulation. % [ node_num, junk ] = size ( p ); [ tri_num, junk ] = size ( t ); p = p'; t = t'; node_show = 0; triangle_show = 1; triangulation_order3_plot ( 'p21_mesh.eps', node_num, p, tri_num, ... t, node_show, triangle_show ); % % Write a text file containing the nodes. % r8mat_write ( 'p21_nodes.txt', 2, node_num, p ); % % Write a text file containing the triangles. % i4mat_write ( 'p21_elements.txt', 3, tri_num, t ); rmpath ( '../distmesh' ) return end