1## Copyright (C) 2021 David Legland 2## All rights reserved. 3## 4## Redistribution and use in source and binary forms, with or without 5## modification, are permitted provided that the following conditions are met: 6## 7## 1 Redistributions of source code must retain the above copyright notice, 8## this list of conditions and the following disclaimer. 9## 2 Redistributions in binary form must reproduce the above copyright 10## notice, this list of conditions and the following disclaimer in the 11## documentation and/or other materials provided with the distribution. 12## 13## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS'' 14## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15## IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16## ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR 17## ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18## DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 19## SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 20## CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 21## OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 22## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 23## 24## The views and conclusions contained in the software and documentation are 25## those of the authors and should not be interpreted as representing official 26## policies, either expressed or implied, of the copyright holders. 27 28function c = vectorCross3d(a,b) 29%VECTORCROSS3D Vector cross product faster than inbuilt MATLAB cross. 30% 31% C = vectorCross3d(A, B) 32% returns the cross product of the 3D vectors A and B, that is: 33% C = A x B 34% A and B must be N-by-3 element vectors. If either A or B is a 1-by-3 35% row vector, the result C will have the size of the other input and will 36% be the concatenation of each row's cross product. 37% 38% Example 39% v1 = [2 0 0]; 40% v2 = [0 3 0]; 41% vectorCross3d(v1, v2) 42% ans = 43% 0 0 6 44% 45% 46% Class support for inputs A,B: 47% float: double, single 48% 49% See also DOT. 50 51% Sven Holcombe 52 53% needed_colons = max([3, length(size(a)), length(size(b))]) - 3; 54% tmp_colon = {':'}; 55% clnSet = tmp_colon(ones(1, needed_colons)); 56% 57% c = bsxfun(@times, a(:,[2 3 1],clnSet{:}), b(:,[3 1 2],clnSet{:})) - ... 58% bsxfun(@times, b(:,[2 3 1],clnSet{:}), a(:,[3 1 2],clnSet{:})); 59 60% deprecation warning 61warning('geom3d:deprecated', ... 62 [mfilename ' is deprecated, use ''crossProduct3d'' instead']); 63 64sza = size(a); 65szb = size(b); 66 67% Initialise c to the size of a or b, whichever has more dimensions. If 68% they have the same dimensions, initialise to the larger of the two 69switch sign(numel(sza) - numel(szb)) 70 case 1 71 c = zeros(sza); 72 case -1 73 c = zeros(szb); 74 otherwise 75 c = zeros(max(sza, szb)); 76end 77 78c(:) = bsxfun(@times, a(:,[2 3 1],:), b(:,[3 1 2],:)) - ... 79 bsxfun(@times, b(:,[2 3 1],:), a(:,[3 1 2],:)); 80