Mercurial > octave-antonio
view scripts/general/trapz.m @ 20158:7503499a252b stable
doc: Update docstrings to have one sentence summary as first line.
Update scripts in audio, elfun, general, geometry, and image directories.
* scripts/audio/@audioplayer/__get_properties__.m,
scripts/audio/@audioplayer/audioplayer.m, scripts/audio/@audioplayer/get.m,
scripts/audio/@audioplayer/isplaying.m, scripts/audio/@audioplayer/play.m,
scripts/audio/@audioplayer/playblocking.m, scripts/audio/@audioplayer/set.m,
scripts/audio/@audioplayer/subsasgn.m, scripts/audio/@audioplayer/subsref.m,
scripts/audio/@audiorecorder/audiorecorder.m,
scripts/audio/@audiorecorder/get.m,
scripts/audio/@audiorecorder/getaudiodata.m,
scripts/audio/@audiorecorder/getplayer.m,
scripts/audio/@audiorecorder/isrecording.m,
scripts/audio/@audiorecorder/play.m, scripts/audio/@audiorecorder/record.m,
scripts/audio/@audiorecorder/recordblocking.m,
scripts/audio/@audiorecorder/set.m, scripts/audio/@audiorecorder/stop.m,
scripts/audio/@audiorecorder/subsasgn.m,
scripts/audio/@audiorecorder/subsref.m, scripts/audio/lin2mu.m,
scripts/audio/mu2lin.m, scripts/audio/record.m, scripts/audio/sound.m,
scripts/audio/soundsc.m, scripts/audio/wavread.m, scripts/audio/wavwrite.m,
scripts/elfun/cosd.m, scripts/elfun/sind.m, scripts/elfun/tand.m,
scripts/general/accumarray.m, scripts/general/accumdim.m,
scripts/general/bitcmp.m, scripts/general/bitget.m, scripts/general/bitset.m,
scripts/general/blkdiag.m, scripts/general/cart2pol.m,
scripts/general/cart2sph.m, scripts/general/cell2mat.m,
scripts/general/celldisp.m, scripts/general/chop.m,
scripts/general/circshift.m, scripts/general/common_size.m,
scripts/general/cplxpair.m, scripts/general/cumtrapz.m,
scripts/general/dblquad.m, scripts/general/deal.m, scripts/general/del2.m,
scripts/general/display.m, scripts/general/divergence.m,
scripts/general/fieldnames.m, scripts/general/flip.m,
scripts/general/flipdim.m, scripts/general/fliplr.m, scripts/general/flipud.m,
scripts/general/gradient.m, scripts/general/interp3.m,
scripts/general/interpft.m, scripts/general/interpn.m,
scripts/general/loadobj.m, scripts/general/logspace.m,
scripts/general/methods.m, scripts/general/nargchk.m,
scripts/general/narginchk.m, scripts/general/nargoutchk.m,
scripts/general/nextpow2.m, scripts/general/nthargout.m,
scripts/general/num2str.m, scripts/general/pol2cart.m,
scripts/general/polyarea.m, scripts/general/postpad.m,
scripts/general/prepad.m, scripts/general/profile.m, scripts/general/quadgk.m,
scripts/general/quadl.m, scripts/general/quadv.m, scripts/general/randi.m,
scripts/general/rat.m, scripts/general/repmat.m, scripts/general/rot90.m,
scripts/general/rotdim.m, scripts/general/saveobj.m, scripts/general/shift.m,
scripts/general/shiftdim.m, scripts/general/sortrows.m,
scripts/general/sph2cart.m, scripts/general/structfun.m,
scripts/general/subsindex.m, scripts/general/trapz.m,
scripts/general/triplequad.m, scripts/geometry/delaunayn.m,
scripts/geometry/dsearch.m, scripts/geometry/dsearchn.m,
scripts/geometry/griddata.m, scripts/geometry/griddata3.m,
scripts/geometry/griddatan.m, scripts/geometry/inpolygon.m,
scripts/geometry/rectint.m, scripts/geometry/tsearchn.m,
scripts/geometry/voronoi.m, scripts/geometry/voronoin.m,
scripts/help/__unimplemented__.m, scripts/help/doc.m,
scripts/help/doc_cache_create.m, scripts/help/get_first_help_sentence.m,
scripts/help/help.m, scripts/help/lookfor.m, scripts/help/print_usage.m,
scripts/help/type.m, scripts/help/which.m, scripts/image/autumn.m,
scripts/image/bone.m, scripts/image/brighten.m, scripts/image/cmpermute.m,
scripts/image/colorcube.m, scripts/image/contrast.m, scripts/image/cool.m,
scripts/image/copper.m, scripts/image/cubehelix.m, scripts/image/flag.m,
scripts/image/gmap40.m, scripts/image/gray.m, scripts/image/gray2ind.m,
scripts/image/hot.m, scripts/image/hsv.m, scripts/image/image.m,
scripts/image/imagesc.m, scripts/image/imfinfo.m, scripts/image/imformats.m,
scripts/image/imread.m, scripts/image/imshow.m, scripts/image/imwrite.m,
scripts/image/iscolormap.m, scripts/image/jet.m, scripts/image/lines.m,
scripts/image/ntsc2rgb.m, scripts/image/ocean.m, scripts/image/pink.m,
scripts/image/prism.m, scripts/image/rainbow.m, scripts/image/rgb2ntsc.m,
scripts/image/spinmap.m, scripts/image/spring.m, scripts/image/summer.m,
scripts/image/white.m, scripts/image/winter.m:
Update docstrings to have one sentence summary as first line.
Re-structure to have line lengths <= 80 chars.
author | Rik <rik@octave.org> |
---|---|
date | Sun, 03 May 2015 09:36:20 -0700 |
parents | 9fc020886ae9 |
children |
line wrap: on
line source
## Copyright (C) 2000-2015 Kai Habel ## ## 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{q} =} trapz (@var{y}) ## @deftypefnx {Function File} {@var{q} =} trapz (@var{x}, @var{y}) ## @deftypefnx {Function File} {@var{q} =} trapz (@dots{}, @var{dim}) ## ## Numerically evaluate the integral of points @var{y} using the trapezoidal ## method. ## ## @w{@code{trapz (@var{y})}} computes the integral of @var{y} along the first ## non-singleton dimension. When the argument @var{x} is omitted an equally ## spaced @var{x} vector with unit spacing (1) is assumed. ## @code{trapz (@var{x}, @var{y})} evaluates the integral with respect to the ## spacing in @var{x} and the values in @var{y}. This is useful if the points ## in @var{y} have been sampled unevenly. ## ## If the optional @var{dim} argument is given, operate along this dimension. ## ## Application Note: If @var{x} is not specified then unit spacing will be ## used. To scale the integral to the correct value you must multiply by the ## actual spacing value (deltaX). As an example, the integral of @math{x^3} ## over the range [0, 1] is @math{x^4/4} or 0.25. The following code uses ## @code{trapz} to calculate the integral in three different ways. ## ## @example ## @group ## x = 0:0.1:1; ## y = x.^3; ## q = trapz (y) ## @result{} q = 2.525 # No scaling ## q * 0.1 ## @result{} q = 0.2525 # Approximation to integral by scaling ## trapz (x, y) ## @result{} q = 0.2525 # Same result by specifying @var{x} ## @end group ## @end example ## ## @seealso{cumtrapz} ## @end deftypefn ## Author: Kai Habel <kai.habel@gmx.de> ## ## also: June 2000 - Paul Kienzle (fixes,suggestions) ## 2006-05-12 David Bateman - Modified for NDArrays function z = trapz (x, y, dim) if (nargin < 1) || (nargin > 3) print_usage (); endif have_xy = have_dim = false; if (nargin == 3) have_xy = true; have_dim = true; elseif (nargin == 2) if (! size_equal (x, y) && isscalar (y)) dim = y; have_dim = true; else have_xy = true; endif endif if (have_xy) nd = ndims (y); sz = size (y); else nd = ndims (x); sz = size (x); endif if (! have_dim) ## Find the first non-singleton dimension. (dim = find (sz > 1, 1)) || (dim = 1); else if (!(isscalar (dim) && dim == fix (dim)) || !(1 <= dim && dim <= nd)) error ("trapz: DIM must be an integer and a valid dimension"); endif endif n = sz(dim); idx1 = idx2 = repmat ({':'}, [nd, 1]); idx1{dim} = 2 : n; idx2{dim} = 1 : (n - 1); if (! have_xy) z = 0.5 * sum (x(idx1{:}) + x(idx2{:}), dim); else if (isvector (x) && ! isvector (y)) if (length (x) != sz(dim)) error ("trapz: length of X and length of Y along DIM must match"); endif ## Reshape vector to point along dimension DIM shape = ones (nd, 1); shape(dim) = sz(dim); x = reshape (x, shape); z = 0.5 * sum (bsxfun (@times, diff (x), y(idx1{:}) + y(idx2{:})), dim); else if (! size_equal (x, y)) error ("trapz: X and Y must have same shape"); endif z = 0.5 * sum (diff (x, 1, dim) .* (y(idx1{:}) + y(idx2{:})), dim); endif endif endfunction %!assert (trapz (1:5), 12) %!assert (trapz (0:0.5:2,1:5), 6) %!assert (trapz ([1:5;1:5].',1), [12,12]) %!assert (trapz ([1:5;1:5],2), [12;12]) %!assert (trapz (repmat (reshape (1:5,1,1,5),2,2), 3), [12 12; 12 12]) %!assert (trapz ([0:0.5:2;0:0.5:2].',[1:5;1:5].',1), [6, 6]) %!assert (trapz ([0:0.5:2;0:0.5:2],[1:5;1:5],2), [6; 6]) %!assert (trapz (repmat (reshape ([0:0.5:2],1,1,5),2,2), ... %! repmat (reshape (1:5,1,1,5),2,2), 3), [6 6; 6 6]) %!assert (trapz (0:0.5:2,[(1:5)',(1:5)']), [6, 6]) %!assert (trapz (0:0.5:2,[(1:5);(1:5)],2), [6; 6]) %!assert (trapz (0:0.5:2,repmat (reshape (1:5,1,1,5),2,2),3), [6 6; 6 6])