Mercurial > octave
view scripts/general/polyarea.m @ 30893:e1788b1a315f
maint: Use "fcn" as preferred abbreviation for "function" in m-files.
* accumarray.m, accumdim.m, quadl.m, quadv.m, randi.m, structfun.m,
__is_function__.m, uigetfile.m, uimenu.m, uiputfile.m, doc_cache_create.m,
colorspace_conversion_input_check.m, imageIO.m, argnames.m, vectorize.m,
vectorize.m, normest1.m, inputname.m, nthargout.m, display_info_file.m,
decic.m, ode15i.m, ode15s.m, ode23.m, ode23s.m, ode45.m, odeset.m,
check_default_input.m, integrate_adaptive.m, ode_event_handler.m,
runge_kutta_23.m, runge_kutta_23s.m, runge_kutta_45_dorpri.m,
runge_kutta_interpolate.m, starting_stepsize.m, __all_opts__.m, fminbnd.m,
fminsearch.m, fminunc.m, fsolve.m, fzero.m, sqp.m, fplot.m, plotyy.m,
__bar__.m, __ezplot__.m, flat_entry.html, profexport.m, movfun.m, bicg.m,
bicgstab.m, cgs.m, eigs.m, gmres.m, pcg.m, __alltohandles__.m, __sprand__.m,
qmr.m, tfqmr.m, dump_demos.m:
Replace "func", "fun", "fn" in documentation and variable names with "fcn".
author | Rik <rik@octave.org> |
---|---|
date | Mon, 04 Apr 2022 18:14:56 -0700 |
parents | 5d3faba0342e |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 1999-2022 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 {} {@var{a} =} polyarea (@var{x}, @var{y}) ## @deftypefnx {} {@var{a} =} polyarea (@var{x}, @var{y}, @var{dim}) ## ## Determine area of a polygon by triangle method. ## ## The variables @var{x} and @var{y} define the vertex pairs, and must ## therefore have the same shape. They can be either vectors or arrays. If ## they are arrays then the columns of @var{x} and @var{y} are treated ## separately and an area returned for each. ## ## If the optional @var{dim} argument is given, then @code{polyarea} works ## along this dimension of the arrays @var{x} and @var{y}. ## ## @end deftypefn ## FIXME: Add moments for centroid, etc. ## ## Bugs and limitations: ## Probably ought to be an optional check to make sure that ## traversing the vertices doesn't make any sides cross ## (Is simple closed curve the technical definition of this?). function a = polyarea (x, y, dim) if (nargin < 2) print_usage (); elseif (! size_equal (x, y)) error ("polyarea: X and Y must have the same shape"); endif if (nargin == 2) a = abs (sum (x .* (circshift (y, -1) - circshift (y, 1)))) / 2; else a = abs (sum (x .* (circshift (y, -1, dim) - circshift (y, 1, dim)), dim)) / 2; endif endfunction %!shared x, y %! x = [1;1;3;3;1]; %! y = [1;3;3;1;1]; %!assert (polyarea (x,y), 4, eps) %!assert (polyarea ([x,x],[y,y]), [4,4], eps) %!assert (polyarea ([x,x],[y,y],1), [4,4], eps) %!assert (polyarea ([x,x]',[y,y]',2), [4;4], eps)