update packages

[CreaPhase.git] / octave_packages / m / plot / ndgrid.m

diff --git a/octave_packages/m/plot/ndgrid.m b/octave_packages/m/plot/ndgrid.m
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+## Copyright (C) 2006-2012 Alexander Barth
+##
+## 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{y1}, @var{y2}, @dots{}, @var{y}n] =} ndgrid (@var{x1}, @var{x2}, @dots{}, @var{x}n)
+## @deftypefnx {Function File} {[@var{y1}, @var{y2}, @dots{}, @var{y}n] =} ndgrid (@var{x})
+## Given n vectors @var{x1}, @dots{} @var{x}n, @code{ndgrid} returns
+## n arrays of dimension n. The elements of the i-th output argument
+## contains the elements of the vector @var{x}i repeated over all
+## dimensions different from the i-th dimension.  Calling ndgrid with
+## only one input argument @var{x} is equivalent of calling ndgrid with
+## all n input arguments equal to @var{x}:
+##
+## [@var{y1}, @var{y2}, @dots{},  @var{y}n] = ndgrid (@var{x}, @dots{}, @var{x})
+## @seealso{meshgrid}
+## @end deftypefn
+
+## Author: Alexander Barth <abarth@marine.usf.edu>
+
+function varargout = ndgrid (varargin)
+
+  if (nargin == 1)
+    n = max ([nargout, 2]);
+    ## If only one input argument is given, repeat it n-times
+    varargin(1:n) = varargin(1);
+  elseif (nargin >= nargout)
+    n = max ([nargin, 2]);
+  else
+    error ("ndgrid: wrong number of input arguments");
+  endif
+
+  ## Determine the size of the output arguments
+
+  shape = zeros (1, n);
+
+  for i = 1:n
+    if (! isvector (varargin{i}))
+      error ("ndgrid: arguments must be vectors");
+    endif
+
+    shape(i) = length (varargin{i});
+  endfor
+
+  for i = 1:n
+    ## size for reshape
+    r = ones (1, n);
+    r(i) = shape(i);
+
+    ## size for repmat
+    s = shape;
+    s(i) = 1;
+
+    varargout{i} = repmat (reshape (varargin{i}, r), s);
+  endfor
+
+endfunction
+
+%!test
+%! x = 1:2;
+%! y = 1:3;
+%! z = 1:4;
+%! [XX, YY, ZZ] = ndgrid (x, y, z);
+%! assert (size_equal (XX, YY, ZZ));
+%! assert (ndims (XX), 3);
+%! assert (size (XX), [2, 3, 4]);
+%! assert (XX(1) * YY(1) * ZZ(1), x(1) * y(1) * z(1));
+%! assert (XX(end) * YY(end) * ZZ(end), x(end) * y(end) * z(end));
+
+%!test
+%! x = 1:2;
+%! y = 1:3;
+%! [XX1, YY1] = meshgrid (x, y);
+%! [XX2, YY2] = ndgrid (x, y);
+%! assert (size_equal (XX1, YY1));
+%! assert (size_equal (XX2, YY2));
+%! assert (ndims (XX1), 2);
+%! assert (size (XX1), [3, 2]);
+%! assert (size (XX2), [2, 3]);
+%! assert (XX2(1) * YY2(1), x(1) * y(1));
+%! assert (XX2(end) * YY2(end), x(end) * y(end));
+%! assert (XX1, XX2.');
+%! assert (YY1, YY2.');