Mercurial > forge
view extra/quaternion-legacy/inst/qinv.m @ 9892:8ad402be2313 octave-forge
main/quaternion --> extra/quaternion-legacy, extra/quaternion_oo --> main/quaternion
author | paramaniac |
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date | Wed, 28 Mar 2012 03:16:58 +0000 |
parents | main/quaternion/inst/qinv.m@a93f2e0352f2 |
children |
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## Copyright (C) 1998, 2000, 2005, 2007 ## Auburn University. All rights reserved. ## ## 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; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {} qinv (@var{q}) ## Return the inverse of a quaternion. ## ## @example ## q = [w, x, y, z] = w*i + x*j + y*k + z ## qmult (q, qinv (q)) = 1 = [0 0 0 1] ## @end example ## @end deftypefn ## Author: A. S. Hodel <a.s.hodel@eng.auburn.edu> ## Adapted-By: jwe function retval = qinv (q) if (nargin != 1) print_usage (); endif if (norm (q) != 0) retval = qconj (q) / sum (q .* q); else error ("qinv: zero quaternion passed!"); endif endfunction