X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?p=CreaPhase.git;a=blobdiff_plain;f=octave_packages%2Fgeometry-1.5.0%2Fgeom2d%2Fcentroid.m;fp=octave_packages%2Fgeometry-1.5.0%2Fgeom2d%2Fcentroid.m;h=ca8b258404f95dfb102d5be6d224044c79658382;hp=0000000000000000000000000000000000000000;hb=f5f7a74bd8a4900f0b797da6783be80e11a68d86;hpb=1705066eceaaea976f010f669ce8e972f3734b05 diff --git a/octave_packages/geometry-1.5.0/geom2d/centroid.m b/octave_packages/geometry-1.5.0/geom2d/centroid.m new file mode 100644 index 0000000..ca8b258 --- /dev/null +++ b/octave_packages/geometry-1.5.0/geom2d/centroid.m @@ -0,0 +1,129 @@ +%% Copyright (c) 2011, INRA +%% 2003-2011, David Legland +%% 2011 Adapted to Octave by Juan Pablo Carbajal +%% +%% All rights reserved. +%% (simplified BSD License) +%% +%% Redistribution and use in source and binary forms, with or without +%% modification, are permitted provided that the following conditions are met: +%% +%% 1. Redistributions of source code must retain the above copyright notice, this +%% list of conditions and the following disclaimer. +%% +%% 2. Redistributions in binary form must reproduce the above copyright notice, +%% this list of conditions and the following disclaimer in the documentation +%% and/or other materials provided with the distribution. +%% +%% THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +%% AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +%% IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +%% ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE +%% LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR +%% CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF +%% SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS +%% INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN +%% CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) +%% ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +%% POSSIBILITY OF SUCH DAMAGE. +%% +%% The views and conclusions contained in the software and documentation are +%% those of the authors and should not be interpreted as representing official +%% policies, either expressed or implied, of copyright holder. + +%% -*- texinfo -*- +%% @deftypefn {Function File} {@var{c} = } centroid (@var{points}) +%% @deftypefnx {Function File} {@var{c} = } centroid (@var{px}, @var{py}) +%% @deftypefnx {Function File} {@var{c} = } centroid (@dots{}, @var{mass}) +%% Compute centroid (center of mass) of a set of points. +%% +%% Computes the ND-dimensional centroid of a set of points. +%% @var{points} is an array with as many rows as the number of points, and as +%% many columns as the number of dimensions. +%% @var{px} and @var{py} are two column vectors containing coordinates of the +%% 2-dimensional points. +%% The result @var{c} is a row vector with ND columns. +%% +%% If @var{mass} is given, computes center of mass of @var{points}, weighted by coefficient @var{mass}. +%% @var{points} is a Np-by-Nd array, @var{mass} is Np-by-1 array, and @var{px} and @var{py} are +%% also both Np-by-1 arrays. +%% +%% Example: +%% +%% @example +%% pts = [2 2;6 1;6 5;2 4]; +%% centroid(pts) +%% ans = +%% 4 3 +%%@end example +%% +%% @seealso{points2d, polygonCentroid} +%% @end deftypefn + +function center = centroid(varargin) + + %% extract input arguments + + % use empty mass by default + mass = []; + + if nargin==1 + % give only array of points + pts = varargin{1}; + + elseif nargin==2 + % either POINTS+MASS or PX+PY + var = varargin{1}; + if size(var, 2)>1 + % arguments are POINTS, and MASS + pts = var; + mass = varargin{2}; + else + % arguments are PX and PY + pts = [var varargin{2}]; + end + + elseif nargin==3 + % arguments are PX, PY, and MASS + pts = [varargin{1} varargin{2}]; + mass = varargin{3}; + end + + %% compute centroid + + if isempty(mass) + % no weight + center = mean(pts); + + else + % format mass to have sum equal to 1, and column format + mass = mass(:)/sum(mass(:)); + + % compute weighted centroid + center = sum(bsxfun(@times, pts, mass), 1); + % equivalent to: + % center = sum(pts .* mass(:, ones(1, size(pts, 2)))); + end + +endfunction + +%!test +%! points = [0 0;10 0;10 10;0 10]; +%! centro = centroid(points); +%! assert ([5 5], centro, 1e-6); + +%!test +%! points = [0 0;10 0;10 10;0 10]; +%! centro = centroid(points(:,1), points(:,2)); +%! assert ([5 5], centro, 1e-6); + +%!test +%! points = [0 0;30 0;30 30;0 30]; +%! centro = centroid(points, [1;1;1;3]); +%! assert ([10 20], centro, 1e-6); + +%!test +%! points = [0 0;30 0;30 30;0 30]; +%! centro = centroid(points(:,1), points(:,2), [1;1;1;3]); +%! assert ([10 20], centro, 1e-6); +