Mercurial > octave-nkf
view scripts/polynomial/polyder.m @ 20651:e54ecb33727e
lo-array-gripes.cc: Remove FIXME's related to buffer size.
* lo-array-gripes.cc: Remove FIXME's related to buffer size. Shorten sprintf
buffers from 100 to 64 characters (still well more than 19 required).
Use 'const' decorator on constant value for clarity. Remove extra space
between variable and array bracket.
author | Rik <rik@octave.org> |
---|---|
date | Mon, 12 Oct 2015 21:13:47 -0700 |
parents | 83792dd9bcc1 |
children |
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## Copyright (C) 1994-2015 John W. Eaton ## ## 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} {} polyder (@var{p}) ## @deftypefnx {Function File} {[@var{k}] =} polyder (@var{a}, @var{b}) ## @deftypefnx {Function File} {[@var{q}, @var{d}] =} polyder (@var{b}, @var{a}) ## Return the coefficients of the derivative of the polynomial whose ## coefficients are given by the vector @var{p}. ## ## If a pair of polynomials is given, return the derivative of the product ## @math{@var{a}*@var{b}}. ## ## If two inputs and two outputs are given, return the derivative of the ## polynomial quotient @math{@var{b}/@var{a}}. The quotient numerator is ## in @var{q} and the denominator in @var{d}. ## @seealso{polyint, polyval, polyreduce} ## @end deftypefn ## Author: Tony Richardson <arichard@stark.cc.oh.us> ## Created: June 1994 ## Adapted-By: jwe function [q, d] = polyder (p, a) if (nargin == 1 || nargin == 2) if (! isvector (p)) error ("polyder: argument must be a vector"); endif if (nargin == 2) if (! isvector (a)) error ("polyder: argument must be a vector"); endif if (nargout == 1) ## derivative of p*a returns a single polynomial q = polyder (conv (p, a)); else ## derivative of p/a returns numerator and denominator d = conv (a, a); if (numel (p) == 1) q = -p * polyder (a); elseif (numel (a) == 1) q = a * polyder (p); else q = conv (polyder (p), a) - conv (p, polyder (a)); q = polyreduce (q); endif ## remove common factors from numerator and denominator x = polygcd (q, d); if (length (x) != 1) q = deconv (q, x); d = deconv (d, x); endif ## move all the gain into the numerator q /= d(1); d /= d(1); endif else lp = numel (p); if (lp == 1) q = 0; return; elseif (lp == 0) q = []; return; endif ## Force P to be a row vector. p = p(:).'; q = p(1:(lp-1)) .* [(lp-1):-1:1]; endif else print_usage (); endif endfunction %!assert (polyder ([1, 2, 3], [2, 2])) %!assert (polyder (13), 0) %!error polyder ([]) %!error polyder (1,2,3) %!error <argument must be a vector> polyder ([1, 2; 3, 4])