Mercurial > octave
view scripts/ode/private/ode_event_handler.m @ 23079:17dc6c7ef427
Ignore ODE event function at t==0 for Matlab compatibility (bug #49919).
* integrate_adaptive.m: new variable have_EventFcn to make code more readable.
* ode_event_handler.m: New persistent variable firstrun. Set to true when
called with 'init'. Toggled back to false after one normal invocation.
Ignore terminating the ODE integration if it occurs on the first time step.
author | Rik <rik@octave.org> |
---|---|
date | Sat, 21 Jan 2017 16:19:38 -0800 |
parents | 3a2b891d0b33 |
children | ef4d915df748 |
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## Copyright (C) 2006-2016 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/>. ## -*- texinfo -*- ## @deftypefn {} {@var{retval} =} ode_event_handler (@var{@@evtfun}, @var{t}, @var{y}, @var{flag}, @var{par1}, @var{par2}, @dots{}) ## ## Return the solution of the event function (@var{@@evtfun}) which is ## specified in the form of a function handle. # ## The second input argument @var{t} is a scalar double and specifies the time ## of the event evaluation. ## ## The third input argument @var{y} may be a column vector of type double ## (for ODEs and DAEs) which specifies the solutions. Alternatives, @var{y} ## may be a cell array (for IDEs and DDEs) which specifies the solutions and ## derivatives. ## ## The fourth input argument @var{flag} is of type string. Valid values are: ## ## @table @option ## @item @qcode{"init"} ## Initialize internal persistent variables of the function ## @code{ode_event_handler} and return an empty cell array of size 4. ## ## @item @qcode{"calc"} ## Evaluate the event function and return the solution @var{retval} as a cell ## array of size 4. ## ## @item @qcode{"done"} ## Clean up internal variables of the function @code{ode_event_handler} and ## return an empty cell array of size 4. ## @end table ## ## If additional input arguments @var{par1}, @var{par2}, @dots{} are given ## these parameters are passed directly to the event function. ## ## This function is an ODE internal helper function and it should never be ## necessary to call it directly. ## @end deftypefn function retval = ode_event_handler (evtfun, t, y, flag = "", varargin) ## No error handling has been implemented in this function to achieve ## the highest performance possible. ## retval{1} is true (to terminate) or false (to continue) ## retval{2} is the index information for which an event occurred ## retval{3} is the time information column vector ## retval{4} is the line by line result information matrix ## These persistent variables store the results and time value from the ## processing in the previous time stamp. ## evtold the results from the event function ## told the time stamp ## yold the ODE result ## retcell the return values cell array ## evtcnt the counter for how often this function has been called persistent evtold told yold retcell; persistent evtcnt = 1; # Don't remove. Required for Octave parser. persistent firstrun = true; if (isempty (flag)) ## Process the event, i.e., ## find the zero crossings for either a rising or falling edge if (! iscell (y)) inpargs = {evtfun, t, y}; else inpargs = {evtfun, t, y{1}, y{2}}; y = y{1}; # Delete cell element 2 endif if (nargin > 4) inpargs = {inpargs{:}, varargin{:}}; endif [evt, term, dir] = feval (inpargs{:}); ## We require that all return values be row vectors evt = evt(:).'; term = term(:).'; dir = dir(:).'; ## Check if one or more signs of the event has changed signum = (sign (evtold) != sign (evt)); if (any (signum)) # One or more values have changed idx = find (signum); # Get the index of the changed values if (any (dir(idx) == 0)) ## Rising or falling (both are possible) ## Don't change anything, keep the index elseif (any (dir(idx) == sign (evt(idx)))) ## Detected rising or falling, need a new index idx = find (dir == sign (evt)); else ## Found a zero crossing but must not be notified idx = []; endif ## Create new output values if a valid index has been found if (! isempty (idx)) ## Change the persistent result cell array if (firstrun) ## Matlab compatibility requires ignoring condition on first run. retcell{1} = false; else retcell{1} = any (term(idx)); # Stop integration or not endif retcell{2}(evtcnt,1) = idx(1,1); # Take first event found ## Calculate the time stamp when the event function returned 0 and ## calculate new values for the integration results, we do both by ## a linear interpolation tnew = t - evt(1,idx) * (t - told) / (evt(1,idx) - evtold(1,idx)); ynew = (y - (t - tnew) * (y - yold) / (t - told)).'; retcell{3}(evtcnt,1) = tnew; retcell{4}(evtcnt,:) = ynew; evtcnt += 1; endif endif firstrun = false; evtold = evt; told = t; yold = y; retval = retcell; elseif (strcmp (flag, "init")) ## Call the event function if an event function has been defined to ## initialize the internal variables of the event function and to get ## a value for evtold. firstrun = true; if (! iscell (y)) inpargs = {evtfun, t, y}; else inpargs = {evtfun, t, y{1}, y{2}}; y = y{1}; # Delete cell element 2 endif if (nargin > 4) inpargs = {inpargs{:}, varargin{:}}; endif [evtold, ~, ~] = feval (inpargs{:}); ## We require that all return values be row vectors evtold = evtold(:).'; told = t; yold = y; evtcnt = 1; retval = retcell = cell (1,4); elseif (strcmp (flag, "done")) ## Clear this event handling function firstrun = true; evtold = told = yold = evtcnt = []; retval = retcell = cell (1,4); endif endfunction