Mercurial > jwe > octave
view scripts/signal/detrend.m @ 31161:6f4c8063b4c2 stable
GitHub-CI: Remove macos-10.15 runners from build matrix.
* .github/workflow/make.yaml (macos): GitHub-hosted runners for macos-10.15 are
being deprecated. Remove them from build matrix. See also:
https://github.com/actions/virtual-environments/issues/5583
author | Markus Mützel <markus.muetzel@gmx.de> |
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date | Wed, 27 Jul 2022 18:30:15 +0200 |
parents | 796f54d4ddbf |
children | 5d3faba0342e |
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######################################################################## ## ## Copyright (C) 1995-2022 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 {} {} detrend (@var{x}, @var{p}) ## If @var{x} is a vector, @code{detrend (@var{x}, @var{p})} removes the ## best fit of a polynomial of order @var{p} from the data @var{x}. ## ## If @var{x} is a matrix, @code{detrend (@var{x}, @var{p})} does the same ## for each column in @var{x}. ## ## The second argument @var{p} is optional. If it is not specified, a value of ## 1 is assumed. This corresponds to removing a linear trend. ## ## The order of the polynomial can also be given as a string, in which case ## @var{p} must be either @qcode{"constant"} (corresponds to @code{@var{p}=0}) ## or @qcode{"linear"} (corresponds to @code{@var{p}=1}). ## @seealso{polyfit} ## @end deftypefn function y = detrend (x, p = 1) if (nargin < 1) print_usage (); endif if (! isnumeric (x) || ndims (x) > 2) error ("detrend: X must be a numeric vector or matrix"); endif if (ischar (p) && strcmpi (p, "constant")) p = 0; elseif (ischar (p) && strcmpi (p, "linear")) p = 1; elseif (! isscalar (p) || p < 0 || p != fix (p)) error ("detrend: P must be \"constant\", \"linear\", or a positive integer"); endif [m, n] = size (x); if (m == 1) x = x.'; endif r = rows (x); b = ((1 : r).' * ones (1, p + 1)) .^ (ones (r, 1) * (0 : p)); y = x - b * (b \ x); if (m == 1) y = y.'; endif endfunction %!test %! N = 32; %! x = (0:1:N-1)/N + 2; %! y = detrend (x); %! assert (abs (y(:)) < 20*eps); %!test %! N = 32; %! t = (0:1:N-1)/N; %! x = t .* t + 2; %! y = detrend (x,2); %! assert (abs (y(:)) < 30*eps); %!test %! N = 32; %! t = (0:1:N-1)/N; %! x = [t;4*t-3].'; %! y = detrend (x); %! assert (abs (y(:)) < 20*eps); %!test %! N = 32; %! x = ((0:1:N-1)/N + 2) * 1i; %! y = detrend (x); %! assert (abs (y(:)) < 20*eps); ## Test input validation %!error <Invalid call> detrend () %!error detrend ("a") %!error detrend (true) %!error detrend (1, "invalid") %!error detrend (1, -1) %!error detrend (1, 1.25)