# HG changeset patch
# User Stefan Miereis <stefan.miereis@gmx.de>
# Date 1449709582 -3600
#      Thu Dec 10 02:06:22 2015 +0100
# Node ID e9e6c110fa3a82d902487ee150d388028e9b541a
# Parent  ce8c465aa6a4776f599ac9ff2cf4095b88fc2e03
move odeplot.m from odepkg to core

* doc/interpreter/diffeq.txi: add DOCSTRING

* scripts/ode/module.mk: include odeplot.m

* scripts/ode/private/: add odeplot.m

diff -r ce8c465aa6a4 -r e9e6c110fa3a doc/interpreter/diffeq.txi
--- a/doc/interpreter/diffeq.txi	Wed Dec 09 15:43:37 2015 -0800
+++ b/doc/interpreter/diffeq.txi	Thu Dec 10 02:06:22 2015 +0100
@@ -153,6 +153,7 @@
 
 @DOCSTRING(odeget)
 
+@DOCSTRING(odeplot)
 
 @node Differential-Algebraic Equations
 @section Differential-Algebraic Equations
diff -r ce8c465aa6a4 -r e9e6c110fa3a scripts/ode/module.mk
--- a/scripts/ode/module.mk	Wed Dec 09 15:43:37 2015 -0800
+++ b/scripts/ode/module.mk	Thu Dec 10 02:06:22 2015 +0100
@@ -12,7 +12,8 @@
   scripts/ode/private/ode_struct_value_check.m \
   scripts/ode/private/runge_kutta_45_dorpri.m \
   scripts/ode/private/runge_kutta_interpolate.m \
-  scripts/ode/private/starting_stepsize.m
+  scripts/ode/private/starting_stepsize.m \
+  scripts/ode/private/odeplot.m
 
 scripts_ode_FCN_FILES = \
   scripts/ode/ode45.m \
diff -r ce8c465aa6a4 -r e9e6c110fa3a scripts/ode/private/odeplot.m
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scripts/ode/private/odeplot.m	Thu Dec 10 02:06:22 2015 +0100
@@ -0,0 +1,83 @@
+## Copyright (C) 2006-2015 Thomas Treichl <treichl@users.sourceforge.net>
+##
+## This file is part of Octave.
+##
+## Octave 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 3 of the License, or (at
+## your option) any later version.
+##
+## Octave 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 Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## Author: Thomas Treichl <treichl@users.sourceforge.net>
+
+%# -*- texinfo -*-
+%# @deftypefn {Function File} {[@var{ret}] =} odeplot (@var{t}, @var{y}, @var{flag})
+%#
+%# Open a new figure window and plot the results from the variable @var{y} of type column vector over time while solving. The types and the values of the input parameter @var{t} and the output parameter @var{ret} depend on the input value @var{flag} that is of type string. If @var{flag} is
+%# @table @option
+%# @item  @code{"init"}
+%# then @var{t} must be a double column vector of length 2 with the first and the last time step and nothing is returned from this function,
+%# @item  @code{""}
+%# then @var{t} must be a double scalar specifying the actual time step and the return value is false (resp. value 0) for 'not stop solving',
+%# @item  @code{"done"}
+%# then @var{t} must be a double scalar specifying the last time step and nothing is returned from this function.
+%# @end table
+%#
+%# This function is called by a ode solver function if it was specified in an options structure with the @command{odeset}. This function is an internal helper function therefore it should never be necessary that this function is called directly by a user. There is only little error detection implemented in this function file to achieve the highest performance.
+%#
+%# For example, solve an anonymous implementation of the "Van der Pol" equation and display the results while solving
+%# @example
+%# fvdb = @@(t,y) [y(2); (1 - y(1)^2) * y(2) - y(1)];
+%# 
+%# opt = odeset ("OutputFcn", @@odeplot, "RelTol", 1e-6);
+%# sol = ode45 (fvdb, [0 20], [2 0], opt);
+%# @end example
+%# @end deftypefn
+%#
+%# @seealso{odepkg}
+
+function [varargout] = odeplot (t, y, flag, varargin)
+
+  ## No input argument check is done for a higher processing speed
+  persistent fig; persistent told; 
+  persistent yold; persistent counter;
+
+  if (strcmp (flag, "init")) 
+    ## Nothing to return, t is either the time slot [tstart tstop]
+    ## or [t0, t1, ..., tn], y is the inital value vector "init"
+    fig = figure; told = t(1,1); yold = y(:,1);
+    counter = 1;
+
+  elseif (isempty (flag))
+    ## Return something in varargout{1}, either false for "not stopping
+    ## the integration" or true for "stopping the integration"
+    counter = counter + 1; figure (fig);
+    told(counter,1) = t(1,1);
+    yold(:,counter) = y(:,1);
+    plot (told, yold, "-o", "markersize", 1); drawnow;
+    varargout{1} = false;
+
+  elseif (strcmp (flag, "done")) 
+    ## Cleanup has to be done, clear the persistent variables because
+    ## we don't need them anymore
+    clear ("figure", "told", "yold", "counter");
+
+  endif
+
+endfunction
+
+
+%!demo
+%! % solve an anonymous implementation of the "Van der Pol" equation
+%! % and display the results while solving
+%! fvdb = @(t,y) [y(2); (1 - y(1)^2) * y(2) - y(1)];
+%! opt = odeset ("OutputFcn", @odeplot, "RelTol", 1e-6);
+%! sol = ode45 (fvdb, [0 20], [2 0], opt);
