Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / odepkg-0.8.2 / odepkg_examples_ide.m

diff --git a/octave_packages/odepkg-0.8.2/odepkg_examples_ide.m b/octave_packages/odepkg-0.8.2/odepkg_examples_ide.m
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+%# Copyright (C) 2008-2012, Thomas Treichl <treichl@users.sourceforge.net>
+%# OdePkg - A package for solving ordinary differential equations and more
+%#
+%# This program is free software; you can redistribute it and/or modify
+%# it under the terms of the GNU General Public License as published by
+%# the Free Software Foundation; either version 2 of the License, or
+%# (at your option) any later version.
+%#
+%# This program is distributed in the hope that it will be useful,
+%# but WITHOUT ANY WARRANTY; without even the implied warranty of
+%# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+%# GNU General Public License for more details.
+%#
+%# You should have received a copy of the GNU General Public License
+%# along with this program; If not, see <http://www.gnu.org/licenses/>.
+
+%# -*- texinfo -*-
+%# @deftypefn {Function File} {[@var{}] =} odepkg_examples_ide (@var{})
+%# Open the IDE examples menu and allow the user to select a demo that will be evaluated.
+%# @end deftypefn
+
+function [] = odepkg_examples_ide ()
+
+  vode = 1; while (vode > 0)
+    clc;
+    fprintf (1, ...
+      ['IDE examples menu:\n', ...
+       '==================\n', ...
+       '\n', ...
+       '   (1) Solve the "Robertson problem" with solver "odebdi"\n', ...
+       '   (2) Solve another "Robertson implementation" with solver "odekdi"\n', ...
+       '   (3) Solve a stiff "Van der Pol" implementation with solver "odebdi"\n', ...
+       '   (4) Solve a stiff "Van der Pol" implementation with solver "odekdi"\n', ...
+       '\n', ...
+       '   Note: There are further IDE examples available with the OdePkg\n', ...
+       '         testsuite functions.\n', ...
+       '\n', ...
+       '   If you have another interesting IDE example that you would like\n', ...
+       '   to share then please modify this file, create a patch and send\n', ...
+       '   your patch to the OdePkg developer team.\n', ...
+       '\n' ]);
+    vode = input ('Please choose a number from above or press <Enter> to return: ');
+    clc; if (vode > 0 && vode < 5)
+      %# We can't use the function 'demo' directly here because it does
+      %# not allow to run other functions within a demo.
+      vexa = example (mfilename (), vode);
+      disp (vexa); eval (vexa);
+      input ('Press <Enter> to continue: ');
+    end %# if (vode > 0)
+  end %# while (vode > 0)
+
+%!demo
+%! # Solve the "Robertson problem" that is given as a function handle
+%! # to an implicite differential equation implementation.
+%!
+%! function [vres] = firobertson (vt, vy, vyd, varargin)
+%!   vres(1,1) = -0.04*vy(1) + 1e4*vy(2)*vy(3) - vyd(1);
+%!   vres(2,1) =  0.04*vy(1) - 1e4*vy(2)*vy(3) - 3e7*vy(2)^2-vyd(2);
+%!   vres(3,1) =  vy(1) + vy(2) + vy(3) - 1;
+%! endfunction
+%!
+%! vopt = odeset ("NormControl", "on");
+%! vsol = odebdi (@firobertson, [0, 1e5], [1, 0, 0], [-4e-2, 4e-2, 0], vopt);
+%! plot (vsol.x, vsol.y);
+
+%!demo
+%! # Solve the "Robertson problem" that is given as a function handle
+%! # to an implicite differential equation implementation.
+%!
+%! function [vres] = firobertson (vt, vy, vyd, varargin)
+%!   vres(1,1) = -0.04*vy(1) + 1e4*vy(2)*vy(3) - vyd(1);
+%!   vres(2,1) =  0.04*vy(1) - 1e4*vy(2)*vy(3) - 3e7*vy(2)^2-vyd(2);
+%!   vres(3,1) =  vy(1) + vy(2) + vy(3) - 1;
+%! endfunction
+%!
+%! vopt = odeset ("NormControl", "on");
+%! vsol = odekdi (@firobertson, [0, 1e5], [1, 0, 0], [-4e-2, 4e-2, 0], vopt);
+%! plot (vsol.x, vsol.y);
+
+%!demo
+%! # Solve the "Van der Pol" problem that is given as a function
+%! # handle to an implicite differential equation implementation.
+%!
+%! function [vres] = fvanderpol (vt, vy, vyd, varargin)
+%!   mu = varargin{1};
+%!   vres = [vy(2) - vyd(1); 
+%!           mu * (1 - vy(1)^2) * vy(2) - vy(1) - vyd(2)];
+%! endfunction
+%!
+%! vopt = odeset ("NormControl", "on", "RelTol", 1e-8, "MaxStep", 1e-2);
+%! vsol = odebdi (@fvanderpol, [0, 20], [2; 0], [0; -2], vopt, 10);
+%! plot (vsol.x, vsol.y);
+
+%!demo
+%! # Solve the "Van der Pol" problem that is given as a function
+%! # handle to an implicite differential equation implementation.
+%!
+%! function [vres] = fvanderpol (vt, vy, vyd, varargin)
+%!   mu = varargin{1};
+%!   vres = [vy(2) - vyd(1); 
+%!           mu * (1 - vy(1)^2) * vy(2) - vy(1) - vyd(2)];
+%! endfunction
+%!
+%! vsol = odekdi (@fvanderpol, [0, 1000], [2; 0], [0; -2], 500);
+%! plot (vsol.x, vsol.y);
+
+%# Local Variables: ***
+%# mode: octave ***
+%# End: ***