Mercurial > forge
view main/quaternion/inst/@quaternion/mpower.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 | extra/quaternion_oo/inst/@quaternion/mpower.m@865de247ab76 |
children | 85ae7bc60c36 |
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## Copyright (C) 2010, 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 -*- ## Matrix power operator of quaternions. Used by Octave for "q^x". ## Author: Lukas Reichlin <lukas.reichlin@gmail.com> ## Created: May 2010 ## Version: 0.2 function q = mpower (a, b) [r, c] = size (a); if (r != c) error ("quaternion: mpower: quaternion matrix must be square"); endif if (r == 1 && c == 1) # a scalar, b? q = a .^ b; # b could be a quaternion elseif (is_real_array (b) && isscalar (b) && fix (b) == b) e = fix (abs (b)); switch (sign (b)) case -1 # q^-e a = inv (a); q = a; case 0 # q^0 q = eye (r); # alternative: q = quaternion (eye (r)) return; case 1; # q^e q = a; endswitch for k = 2 : e q *= a; # improvement?: q^8 = ((q^2)^2)^2, q^9 = (((q^2)^2)^2)*q endfor else error ("quaternion: mpower: case not implemented yet"); q = expm (logm (a) * b); # don't know whether this formula is correct endif ## TODO: - q1 ^ q2 ## - arrays endfunction