Mercurial > forge
view main/quaternion/inst/@quaternion/log.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/log.m@bd074ca343c3 |
children |
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## 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{qlog} =} log (@var{q}) ## Logarithmus naturalis of a quaternion. ## @end deftypefn ## Author: Lukas Reichlin <lukas.reichlin@gmail.com> ## Created: November 2011 ## Version: 0.1 function q = log (q) if (nargin != 1) print_usage (); endif normq = abs (q); normv = normv (q); acossq = acos (q.w ./ normq); q.w = log (normq); q.x = (q.x ./ normv) .* acossq; q.y = (q.y ./ normv) .* acossq; q.z = (q.z ./ normv) .* acossq; ## FIXME: q = quaternion (2, 3, 4, 5) ## p = log (exp (q)) ## p.v is wrong, probably somehow related to acos ## NOTE: p = exp (log (q)) is calculated correctly ## NOTE: qtfm 1.9 returns the same "wrong" result endfunction %!shared A, B %! Aw = [2, 6, 10; 14, 18, 22]; %! Ax = [3, 7, 11; 15, 19, 23]; %! Ay = [4, 8, 12; 16, 20, 24]; %! Az = [5, 9, 13; 17, 21, 25]; %! A = quaternion (Aw, Ax, Ay, Az); %! %! B = exp (log (A)); %! %!assert (A.w, B.w, 1e-4); %!assert (A.x, B.x, 1e-4); %!assert (A.y, B.y, 1e-4); %!assert (A.z, B.z, 1e-4);