update packages

[CreaPhase.git] / octave_packages / m / geometry / delaunay3.m

diff --git a/octave_packages/m/geometry/delaunay3.m b/octave_packages/m/geometry/delaunay3.m
new file mode 100644 (file)
index 0000000..914a9c3
--- /dev/null
+++ b/octave_packages/m/geometry/delaunay3.m
@@ -0,0 +1,77 @@
+## Copyright (C) 1999-2012 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{tetr} =} delaunay3 (@var{x}, @var{y}, @var{z})
+## @deftypefnx {Function File} {@var{tetr} =} delaunay3 (@var{x}, @var{y}, @var{z}, @var{options})
+## Compute the Delaunay triangulation for a 3-D set of points.
+## The return value @var{tetr} is a set of tetrahedrons which satisfies the
+## Delaunay circum-circle criterion, i.e., only a single data point from
+## [@var{x}, @var{y}, @var{z}] is within the circum-circle of the defining
+## tetrahedron.
+##
+## The set of tetrahedrons @var{tetr} is a matrix of size [n, 4].  Each
+## row defines a tetrahedron and the four columns are the four vertices
+## of the tetrahedron.  The value of @code{@var{tetr}(i,j)} is an index into
+## @var{x}, @var{y}, @var{z} for the location of the j-th vertex of the i-th
+## tetrahedron.
+##
+## An optional fourth argument, which must be a string or cell array of strings,
+## contains options passed to the underlying qhull command.
+## See the documentation for the Qhull library for details
+## @url{http://www.qhull.org/html/qh-quick.htm#options}.
+## The default options are @code{@{"Qt", "Qbb", "Qc", "Qz"@}}.
+##
+## If @var{options} is not present or @code{[]} then the default arguments are
+## used.  Otherwise, @var{options} replaces the default argument list. 
+## To append user options to the defaults it is necessary to repeat the 
+## default arguments in @var{options}.  Use a null string to pass no arguments.
+##
+## @seealso{delaunay, delaunayn, convhull, voronoi}
+## @end deftypefn
+
+## Author: Kai Habel <kai.habel@gmx.de>
+
+function tetr = delaunay3 (x, y, z, options)
+
+  if (nargin < 3 || nargin > 4)
+    print_usage ();
+  endif
+
+  if (! (isvector (x) && isvector (y) && isvector (z)
+         && length (x) == length (y) && length(x) == length (z)))
+    error ("delaunay: X, Y, and Z must be the same size");
+  elseif (nargin == 4 && ! (ischar (options) || iscellstr (options)))
+    error ("delaunay3: OPTIONS must be a string or cell array of strings");
+  endif
+
+  if (nargin == 3)
+    tetr = delaunayn ([x(:), y(:), z(:)]);
+  else
+    tetr = delaunayn ([x(:), y(:), z(:)], options);
+  endif
+
+endfunction
+
+
+%!testif HAVE_QHULL
+%! x = [-1, -1, 1, 0, -1]; y = [-1, 1, 1, 0, -1]; z = [0, 0, 0, 1, 1];
+%! assert (sortrows (sort (delaunay3 (x, y, z), 2)), [1,2,3,4;1,2,4,5])
+
+%% FIXME: Need input validation tests
+