Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / quaternion-2.0.0 / @quaternion / diag.m

diff --git a/octave_packages/quaternion-2.0.0/@quaternion/diag.m b/octave_packages/quaternion-2.0.0/@quaternion/diag.m
new file mode 100644 (file)
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+++ b/octave_packages/quaternion-2.0.0/@quaternion/diag.m
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+## Copyright (C) 2010   Lukas F. Reichlin
+##
+## This program 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.
+##
+## This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {@var{q} =} diag (@var{v})
+## @deftypefnx {Function File} {@var{q} =} diag (@var{v}, @var{k})
+## Return a diagonal quaternion matrix with quaternion vector V on diagonal K.
+## The second argument is optional. If it is positive,
+## the vector is placed on the K-th super-diagonal.
+## If it is negative, it is placed on the -K-th sub-diagonal.
+## The default value of K is 0, and the vector is placed
+## on the main diagonal.
+## @end deftypefn
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: May 2010
+## Version: 0.1
+
+function a = diag (a, b = 0)
+
+  if (nargin == 0 || nargin > 2)
+    print_usage ();
+  endif
+
+  a.w = diag (a.w, b);
+  a.x = diag (a.x, b);
+  a.y = diag (a.y, b);
+  a.z = diag (a.z, b);
+
+endfunction
+
+
+%!shared R, S
+%! Q = quaternion (2, 3, 4, 5);
+%! R = diag ([Q, Q, Q]);
+%! W = diag ([2, 2, 2]);
+%! X = diag ([3, 3, 3]);
+%! Y = diag ([4, 4, 4]);
+%! Z = diag ([5, 5, 5]);
+%! S = quaternion (W, X, Y, Z);
+%!assert (R == S);