function meshdemo_2d ( )

%*****************************************************************************80
%
%% MESHDEMO_2D displays some 2D examples of the use of DISTMESH.
%
%  Licensing:
%
%    (C) 2004 Per-Olof Persson. 
%    See COPYRIGHT.TXT for details.
%
%  Modified:
%
%    27 October 2011
%
%  Reference:
%
%    Per-Olof Persson, Gilbert Strang,
%    A Simple Mesh Generator in MATLAB,
%    SIAM Review,
%    Volume 46, Number 2, June 2004, pages 329-345.
%
%  Local parameters:
%
%    Local, integer ITERATION_MAX, the maximum number of iterations that DISTMESH
%    should take.  (The program might take fewer iterations if it detects convergence.)
%
%    Local, real H, the desired initial spacing.  If a uniform mesh density is used,
%    this is the approximate spacing throughout the region.
%
%    Local, pointer FH, an inline formula, or the name of an M file, which calculates
%    the mesh density function.
%
  timestamp ( );

  fprintf ( 1, '\n' );
  fprintf ( 1, 'MESHDEMO_2D\n' );
  fprintf ( 1, '  Demonstrations of the use of DISTMESH.\n' );
%
%  Problem 1, the circle, with spacings H = 0.4, 0.2, 0.1.
%
  iteration_max = 200;
  h = 0.40;
  p01_demo ( iteration_max, h );
  input ( 'Press RETURN' )

  iteration_max = 200;
  h = 0.20;
  p01_demo ( iteration_max, h );
  input ( 'Press RETURN' )

  iteration_max = 200;
  h = 0.10;
  p01_demo ( iteration_max, h );
  input ( 'Press RETURN' )
%
%  Problem 2, unit circle with a hole.
%
  iteration_max = 200;
  h = 0.10;
  p02_demo ( iteration_max, h )

  input ( 'Press RETURN' )
%
%  Problem 3, square with a hole, uniform density.
%
  iteration_max = 200;
  h = 0.15;
  fh = @p03_fh;
  p03_demo ( iteration_max, h, fh )

  input ( 'Press RETURN' )
%
%  Problem 3, square with a hole, finer density near the hole.
%
  iteration_max = 300;
  h = 0.05;
  fh = inline ( 'min(4*sqrt(sum(p.^2,2))-1,2)', 'p' );
  p03_demo ( iteration_max, h, fh )

  input ( 'Press RETURN' )
%
%  Problem 4, hexagon with a hexagonal hole.
%
  iteration_max = 200;
  h = 0.1;
  p04_demo ( iteration_max, h );

  input ( 'Press RETURN' )
%
%  Problem 5, the horn.
%
  iteration_max = 200;
  h = 0.020;
  p05_demo ( iteration_max, h );

  input ( 'Press RETURN' )
%
%  Problem 6, the superellipse.
%  Needs MAPLE to run...
%
  if ( 0 )
    iteration_max = 200;
    h = 0.08;
    p06_demo ( iteration_max, h );
    input ( 'Press RETURN' )
  else
    fprintf ( 1, '\n' );
    fprintf ( 1, '  Skipping problem 6, the superellipse.\n' );
  end
%
%  Problem 7, the bicycle seat.
%  Needs MAPLE to run...
%
  if ( 0 )
    iteration_max = 200;
    h = 0.75;
    p07_demo ( iteration_max, h );
    input ( 'Press RETURN' )
  else
    fprintf ( 1, '\n' );
    fprintf ( 1, '  Skipping problem 7, the bicycle seat.\n' );
  end
%
%  Problem 8, the holey pie slice, uniform density.
%
  iteration_max = 200;
  h = 0.025;
  fh = @huniform;
  p08_demo ( iteration_max, h, fh );
  input ( 'Press RETURN' )
%
%  Problem 8, the holey pie slice, variable density.
%
  iteration_max = 200;
  h = 0.005;
  fh = @p08_fh;
  p08_demo ( iteration_max, h, fh );
  input ( 'Press RETURN' )
%
%  Problem 9, Jeff Borggaard's square with two hexagonal holes.
%
  iteration_max = 200;
  h = 0.08;
  p09_demo ( iteration_max, h );
  input ( 'Press RETURN' )
%
%  Problem 10, a simple square.
%
  iteration_max = 200;
  h = 0.10;
  p10_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Problem 11, the L-shaped region.
%
  iteration_max = 200;
  h = 0.10;
  p11_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Problem 12, John Shadid's H-shaped region.
%
  iteration_max = 200;
  h = 0.05;
  p12_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Problem 13, the Sandia Fork.
%
  iteration_max = 200;
  h = 0.025;
  p13_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Problem 14, Marcus Garvie's Lake Alpha with Beta island.
%
  if ( 0 )
    iteration_max = 50;
    h = 20.0;
    fh = @huniform;
    p14_demo ( iteration_max, h, fh )
    input ( 'Press RETURN' )
  else
    fprintf ( 1, '\n' );
    fprintf ( 1, '  Skipping problem 14.\n' );
  end
%
%  Problem 14, Marcus Garvie's Lake Alpha with Beta island.
%  You may get endless warnings from DELAUNAYN about duplicate points.
%  Shut off this annoying drivel with "warning off".
%
  if ( 0 )
    warning off
    iteration_max = 50;
    h = 10.0;
    fh = @p14_fh;
    p14_demo ( iteration_max, h, fh )
    input ( 'Press RETURN' )
  else
    fprintf ( 1, '\n' );
    fprintf ( 1, '  Skipping problem 14.\n' );
  end
%
%  Problem 15, Sangbum Kim's forward step problem.
%
  iteration_max = 50;
  h = 0.2;
  p15_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Problem 16, Kevin Pond's elbow.
%
  iteration_max = 50;
  h = 0.05;
  p16_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Problem 17, Reuleaux triangle problem.
%
  iteration_max = 50;
  h = 0.05;
  p17_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Problem 18, Dumbbell problem.
%
  iteration_max = 50;
  h = 0.100;
  p18_demo ( iteration_max, h )
  input ( 'Press RETURN' )
%
%  Terminate.
%
  fprintf ( 1, '\n' );
  fprintf ( 1, 'MESHDEMO_2D\n' );
  fprintf ( 1, '  Normal end of execution.\n' );

  fprintf ( 1, '\n' );
  timestamp ( );

  return
end