Add a useful package (from Source forge) for octave

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

diff --git a/octave_packages/quaternion-2.0.0/@quaternion/unit.m b/octave_packages/quaternion-2.0.0/@quaternion/unit.m
new file mode 100644 (file)
index 0000000..8a439f0
--- /dev/null
+++ b/octave_packages/quaternion-2.0.0/@quaternion/unit.m
@@ -0,0 +1,38 @@
+## Copyright (C) 2011   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{qn} =} unit (@var{q})
+## Normalize quaternion to length 1 (unit quaternion).
+##
+## @example
+## q = w + x*i + y*j + z*k
+## unit (q) = q ./ sqrt (w.^2 + x.^2 + y.^2 + z.^2)
+## @end example
+## @end deftypefn
+
+## Author: Lukas Reichlin <lukas.reichlin@gmail.com>
+## Created: November 2011
+## Version: 0.1
+
+function q = unit (a)
+
+  if (nargin != 1)
+    print_usage ();
+  endif
+
+  q = a ./ abs (a);
+
+endfunction