Mercurial > octave-nkf
view scripts/ode/private/hermite_quartic_interpolation.m @ 20568:fcb792acab9b
Moving ode45, odeset, odeget, and levenshtein from odepkg to core.
* libinterp/corefcn/levenshtein.cc: move function from odepkg into core
* libinterp/corefcn/module.mk: include levenshtein.cc
* scripts/ode: move ode45, odeset, odeget, and all dependencies
from odepkg into core
* scripts/module.mk: include them
* doc/interpreter/diffeq.txi: add documentation for ode45,
odeset, odeget
* NEWS: announce functions included with this changeset
* scripts/help/__unimplemented__.m: removed new functions
author | jcorno <jacopo.corno@gmail.com> |
---|---|
date | Thu, 24 Sep 2015 12:58:46 +0200 |
parents | |
children | 6256f6e366ac |
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## Copyright (C) 2014, Jacopo Corno <jacopo.corno@gmail.com> ## 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 {Command} {[@var{x_out}] =} ## hermite_quartic_interpolation (@var{t}, @var{x}, @var{der}, @var{t_out}) ## ## This function file can be called by a ODE solver function in order to ## interpolate the solution at the time @var{t_out} using 4th order ## hermite interpolation. ## ## This function must be called with one output arguments: @var{x_out} ## which contains the evaluation at @var{t_out} of the hermite interpolant. ## ## The first input argument is the vector with two given times. ## ## The second input argument is the vector with the values of the function ## to interpolate at the times specified in @var{t} and at the middle point. ## ## The third input argument is the value of the derivatives of the function ## evaluated at the two extreme points. ## ## @end deftypefn ## ## @seealso{linear_interpolation, quadratic_interpolation, ## hermite_cubic_interpolation, hermite_quintic_interpolation, ## dorpri_interpolation} function x_out = hermite_quartic_interpolation (t, x, der, t_out) # Rescale time on [0,1] s = (t_out - t(1)) / (t(2) - t(1)); # Hermite basis functions # H0 = 1 - 11*s.^2 + 18*s.^3 - 8*s.^4; # H1 = s - 4*s.^2 + 5*s.^3 - 2*s.^4; # H2 = 16*s.^2 - 32*s.^3 + 16*s.^4; # H3 = - 5*s.^2 + 14*s.^3 - 8*s.^4; # H4 = s.^2 - 3*s.^3 + 2*s.^4; x_out = zeros (size (x, 1), length (t_out)); for ii = 1:size (x, 1) x_out(ii,:) = (1 - 11*s.^2 + 18*s.^3 - 8*s.^4)*x(ii,1) ... + ( s - 4*s.^2 + 5*s.^3 - 2*s.^4)*(t(2)-t(1))*der(ii,1) ... + ( 16*s.^2 - 32*s.^3 + 16*s.^4)*x(ii,2) ... + ( - 5*s.^2 + 14*s.^3 - 8*s.^4)*x(ii,3) ... + ( s.^2 - 3*s.^3 + 2*s.^4)*(t(2)-t(1))*der(ii,2); endfor endfunction ## Local Variables: *** ## mode: octave *** ## End: ***