Mercurial > octave
view scripts/polynomial/ppint.m @ 32632:2e484f9f1f18 stable
maint: update Octave Project Developers copyright for the new year
author | John W. Eaton <jwe@octave.org> |
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date | Fri, 22 Dec 2023 12:08:17 -0500 |
parents | 597f3ee61a48 |
children |
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######################################################################## ## ## Copyright (C) 2008-2024 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{ppi} =} ppint (@var{pp}) ## @deftypefnx {} {@var{ppi} =} ppint (@var{pp}, @var{c}) ## Compute the integral of the piecewise polynomial struct @var{pp}. ## ## @var{c}, if given, is the constant of integration. ## @seealso{mkpp, ppval, ppder} ## @end deftypefn function ppi = ppint (pp, c) if (nargin < 1) print_usage (); endif if (! (isstruct (pp) && strcmp (pp.form, "pp"))) error ("ppint: PP must be a structure"); endif [x, p, n, k, d] = unmkpp (pp); p = reshape (p, [], k); ## Get piecewise antiderivatives pi = p / diag (k:-1:1); k += 1; if (nargin == 1) pi(:, k) = 0; else pi(:, k) = repmat (c(:), n, 1); endif ppi = mkpp (x, pi, d); tmp = -cumsum (ppjumps (ppi), length (d) + 1); ppi.coefs(prod (d)+1 : end, k) = tmp(:); endfunction %!shared x,y,pp,ppi %! x = 0:8; %! y = [ ones(size(x)); x+1 ]; %! pp = spline (x, y); %! ppi = ppint (pp); %!assert (ppval (ppi, x), [x; 0.5*x.^2 + x], 1e-14) %!assert (ppi.order, 5)