Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / geometry-1.5.0 / graphs / voronoi2d.m

diff --git a/octave_packages/geometry-1.5.0/graphs/voronoi2d.m b/octave_packages/geometry-1.5.0/graphs/voronoi2d.m
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+%% Copyright (C) 2007-2012 David Legland <david.legland@grignon.inra.fr>
+%% All rights reserved.
+%%
+%% 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 AUTHOR 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.
+%%
+%% 2012 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
+
+%% -*- texinfo -*-
+%% @deftypefn {Function File} {[@var{nodes} @var{edges} @var{faces}] = } voronoi2d (@var{germs})
+%% Compute a voronoi diagram as a graph structure
+%%
+%% [NODES EDGES FACES] = voronoi2d(GERMS)
+%% GERMS an array of points with dimension 2
+%% NODES, EDGES, FACES: usual graph representation, FACES as cell array
+%%
+%% Example
+%% @example
+%%
+%% [n e f] = voronoi2d(rand(100, 2)*100);
+%% drawGraph(n, e);
+%%
+%% @end example
+%%
+%% @end deftypefn
+
+function [nodes edges faces] = voronoi2d(germs)
+  [V C] = voronoin(germs);
+
+  nodes = V(2:end, :);
+  edges = zeros(0, 2);
+  faces = {};
+
+  for i=1:length(C)
+  cell = C{i};
+  if ismember(1, cell)
+    continue;
+  end
+
+  cell = cell-1;
+  edges = [edges; sort([cell' cell([2:end 1])'], 2)]; %#ok<AGROW>
+  faces{length(faces)+1} = cell; %#ok<AGROW>
+  end
+
+  edges = unique(edges, 'rows');
+
+endfunction
+
+%!demo
+%! [n e f] = voronoi2d(rand(100, 2)*100);
+%! drawGraph(n, e);
+%! axis tight