Mercurial > octave
view scripts/ode/private/ode_event_handler.m @ 30893:e1788b1a315f
maint: Use "fcn" as preferred abbreviation for "function" in m-files.
* accumarray.m, accumdim.m, quadl.m, quadv.m, randi.m, structfun.m,
__is_function__.m, uigetfile.m, uimenu.m, uiputfile.m, doc_cache_create.m,
colorspace_conversion_input_check.m, imageIO.m, argnames.m, vectorize.m,
vectorize.m, normest1.m, inputname.m, nthargout.m, display_info_file.m,
decic.m, ode15i.m, ode15s.m, ode23.m, ode23s.m, ode45.m, odeset.m,
check_default_input.m, integrate_adaptive.m, ode_event_handler.m,
runge_kutta_23.m, runge_kutta_23s.m, runge_kutta_45_dorpri.m,
runge_kutta_interpolate.m, starting_stepsize.m, __all_opts__.m, fminbnd.m,
fminsearch.m, fminunc.m, fsolve.m, fzero.m, sqp.m, fplot.m, plotyy.m,
__bar__.m, __ezplot__.m, flat_entry.html, profexport.m, movfun.m, bicg.m,
bicgstab.m, cgs.m, eigs.m, gmres.m, pcg.m, __alltohandles__.m, __sprand__.m,
qmr.m, tfqmr.m, dump_demos.m:
Replace "func", "fun", "fn" in documentation and variable names with "fcn".
author | Rik <rik@octave.org> |
---|---|
date | Mon, 04 Apr 2022 18:14:56 -0700 |
parents | 796f54d4ddbf |
children | 449ed6f427cb |
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######################################################################## ## ## Copyright (C) 2006-2022 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{retval} =} ode_event_handler (@var{@@evtfcn}, @var{t}, @var{y}, @var{flag}, @var{par1}, @var{par2}, @dots{}) ## ## Return the solution of the event function (@var{@@evtfcn}) 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 (evtfcn, 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 = {evtfcn, t, y}; else inpargs = {evtfcn, 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 ## Find events where either rising and falling edges are counted (dir==0) ## or where the specified edge type matches the event edge type. idx = signum & (dir == 0 | dir == sign (evt)); idx = find (idx); # convert logical to numeric index or [] ## 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 idx = idx(1); # Use first event found if there are multiple. retcell{2}(evtcnt,1) = idx; ## 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(idx) * (t - told) / (evt(idx) - evtold(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 = {evtfcn, t, y}; else inpargs = {evtfcn, 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