Mercurial > octave
view scripts/ode/private/integrate_n_steps.m @ 20631:00caf63edcdf
maint: Remove obsolete ODE options from odeset/odeget/ode45.
* odepkg_structure_check.m: Deleted file, replaced in code with
ode_struct_value_check()
* scripts/ode/module.mk: Remove odepkg_structure_check.m from build system.
* ode45.m: Just print_usage(), rather than displaying help, if incorrect
number of arguments supplied. Replace calls to odepkg_structure_check()
with calls to ode_struct_value_check(). Use error ID
"Octave:invalid-input-arg" rather than "OdePkg:InvalidArgument".
Use local variables TimeStepNumber and TimeStepSize since these are no
longer a default part of an ODE options structure. Remove options that
are no longer a part of ODE options structure.
* odeget.m: Remove unused options. Allow unknown options through, but
display a warning.
* odeset.m: Remove unused options. Allow unknown options through, but
dispaly a warning. Use special for loop over structure to simplify code.
Add BIST tests for custom user-defined options and for input validation.
* ode_struct_value_check.m: Rewrite docstring. Return input ode_struct
as output so that function can replace odepk_structure_check. Use
meaningful input variable name ode_struct rather than arg. Use special
for loop syntax over structure to simplify code. Remove checking for
obsolete, non-Matlab options. Use error ID "Octave:invalid-input-arg" rather
than "OdePkg:InvalidArgument". Preface all error and warning messages
with the name of the calling function.
* AbsRel_Norm.m, integrate_const.m, integrate_n_steps.m: Use error ID
"Octave:invalid-input-arg" rather than "OdePkg:InvalidArgument".
* odepkg_event_handle.m: Rephrase sentence in docstring.
author | Rik <rik@octave.org> |
---|---|
date | Fri, 16 Oct 2015 10:31:02 -0700 |
parents | b92f8e148936 |
children | 80e630b37ba1 |
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## Copyright (C) 2013, Roberto Porcu' <roberto.porcu@polimi.it> ## ## 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 {Function File} {@var{solution} =} integrate_n_steps (@var{@@stepper}, @var{@@func}, @var{t0}, @var{x0}, @var{dt}, @var{n}, @var{options}) ## ## This function file can be called by an ODE solver function in order to ## integrate the set of ODEs on the interval @var{[t0,t0 + n*dt]} with a ## constant timestep dt and on a fixed number of steps. ## ## The function returns a structure @var{solution} with two fieldss: @var{t} ## and @var{y}. @var{t} is a column vector and contains the time stamps. ## @var{y} is a matrix in which each column refers to a different unknown ## of the problem and the row number is the same as the @var{t} row number. ## Thus, each row of the matrix @var{y} contains the values of all unknowns at ## the time value contained in the corresponding row in @var{t}. ## ## The first input argument must be a function handle or inline function ## representing the stepper, i.e., the function responsible for step-by-step ## integration. This function discriminates one method from the others. ## ## The second input argument is the order of the stepper. It is needed to ## compute the adaptive timesteps. ## ## The third input argument is a function handle or inline function that ## defines the ODE: ## ## @ifhtml ## @example ## @math{y' = f(t,y)} ## @end example ## @end ifhtml ## @ifnothtml ## @math{y' = f(t,y)}. ## @end ifnothtml ## ## The third input argument is the starting point for the integration. ## ## The fourth argument contains the initial conditions for the ODEs. ## ## The fifth input argument represents the fixed timestep while the sixth ## contains the number of integration steps. ## ## The last argument is a struct with the options that may be needed by the ## stepper. ## @end deftypefn ## ## @seealso{integrate_adaptive, integrate_const} function solution = integrate_n_steps (stepper, func, t0, x0, dt, n, options) solution = struct (); ## first values for time and solution x = x0(:); t = t0; vdirection = odeget (options, "vdirection", [], "fast"); if (sign (dt) != vdirection) error ("Octave:invalid-input-arg", "option 'InitialStep' has a wrong sign"); endif comp = 0.0; tk = t0; options.comp = comp; ## Initialize the OutputFcn if (options.vhaveoutputfunction) if (options.vhaveoutputselection) solution.vretout = x(options.OutputSel,end); else solution.vretout = x; endif feval (options.OutputFcn, tspan, solution.vretout, "init", options.vfunarguments{:}); endif ## Initialize the EventFcn if (options.vhaveeventfunction) odepkg_event_handle (options.Events, t(end), x, "init", options.vfunarguments{:}); endif solution.vcntloop = 2; solution.vcntcycles = 1; vcntiter = 0; solution.vunhandledtermination = true; solution.vcntsave = 2; z = t; u = x; k_vals = feval (func, t , x, options.vfunarguments{:}); for i = 1:n ## Compute the integration step from t to t+dt [s, y, ~, k_vals] = stepper (func, z(end), u(:,end), dt, options, k_vals); [tk, comp] = kahan (tk, comp, dt); options.comp = comp; s(end) = tk; if (options.vhavenonnegative) x(options.NonNegative,end) = abs (x(options.NonNegative,end)); y(options.NonNegative,end) = abs (y(options.NonNegative,end)); endif if (options.vhaveoutputfunction && options.vhaverefine) vSaveVUForRefine = u(:,end); endif ## values on this interval for time and solution z = [t(end);s]; u = [x(:,end),y]; x = [x,u(:,2:end)]; t = [t;z(2:end)]; solution.vcntsave += 1; solution.vcntloop += 1; vcntiter = 0; ## Call OutputFcn only if a valid result has been found. ## Stop integration if function returns false. if (options.vhaveoutputfunction) for vcnt = 0:options.Refine # Approximation between told and t if (options.vhaverefine) # Do interpolation vapproxtime = (vcnt + 1) / (options.Refine + 2); vapproxvals = (1 - vapproxtime) * vSaveVUForRefine ... + (vapproxtime) * y(:,end); vapproxtime = s(end) + vapproxtime*dt; else vapproxvals = x(:,end); vapproxtime = t(end); endif if (options.vhaveoutputselection) vapproxvals = vapproxvals(options.OutputSel); endif vpltret = feval (options.OutputFcn, vapproxtime, vapproxvals, [], options.vfunarguments{:}); if (vpltret) # Leave refinement loop break; endif endfor if (vpltret) # Leave main loop solution.vunhandledtermination = false; break; endif endif ## Call Events function only if a valid result has been found. ## Stop integration if veventbreak is true. if (options.vhaveeventfunction) solution.vevent = odepkg_event_handle (options.Events, t(end), x(:,end), [], options.vfunarguments{:}); if (! isempty (solution.vevent{1}) && solution.vevent{1} == 1) t(solution.vcntloop-1,:) = solution.vevent{3}(end,:); x(:,solution.vcntloop-1) = solution.vevent{4}(end,:)'; solution.vunhandledtermination = false; break; endif endif ## Update counters that count the number of iteration cycles solution.vcntcycles += 1; # Needed for cost statistics vcntiter += 1; # Needed to find iteration problems ## Stop solving because, in the last 5,000 steps, no successful valid ## value has been found if (vcntiter >= 5000) error (["Solving has not been successful. The iterative", " integration loop exited at time t = %f before endpoint at", " tend = %f was reached. This happened because the iterative", " integration loop does not find a valid solution at this time", " stamp. Try to reduce the value of 'InitialStep' and/or", " 'MaxStep' with the command 'odeset'.\n"], s(end), tspan(end)); endif endfor ## Check if integration of the ode has been successful #if (vdirection * z(end) < vdirection * tspan(end)) # if (solution.vunhandledtermination == true) # error ("integrate_n_steps:unexpected_termination", # [" Solving was not successful. ", ... # " The iterative integration loop exited at time", ... # " t = %f before the endpoint at tend = %f was reached. ", ... # " This may happen if the stepsize becomes too small. ", ... # " Try to reduce the value of 'InitialStep'", ... # " and/or 'MaxStep' with the command 'odeset'.\n"], # z(end), tspan(end)); # else # warning ("integrate_n_steps:unexpected_termination", # ["Solver was stopped by a call of 'break'", ... # " in the main iteration loop at time ", ... # " t = %f before the endpoint at tend = %f was reached. ", ... # " This may happen because the @odeplot function ", ... # " returned 'true' or the @event function returned 'true'.\n"], # z(end), tspan(end)); # endif #endif solution.t = t; solution.x = x'; endfunction