Mercurial > forge
view FIXES/cross.m @ 15:a6258505c1c5 octave-forge
Restore octave defaults for non-conformant vectors, but issue a warning so
that the user will clean up their code and compatibility with matlab will
not be an issue.
author | pkienzle |
---|---|
date | Mon, 29 Oct 2001 15:35:28 +0000 |
parents | b0d392ad31a0 |
children | 2ac2777b30bc |
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## Copyright (C) 1995, 1996 Kurt Hornik ## ## 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 2, 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 file. If not, write to the Free Software Foundation, ## 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. ## -*- texinfo -*- ## @deftypefn {Function File} {} cross (@var{x}, @var{y}) ## Computes the vector cross product of the two 3-dimensional vectors ## @var{x} and @var{y}. ## ## @example ## @group ## cross ([1,1,0], [0,1,1]) ## @result{} [ 1; -1; 1 ] ## @end group ## @end example ## ## If @var{x} and @var{y} are two - dimensional matrices the ## cross product is applied along the first dimension with 3 elements. ## ## If cross is given a row vector and a column vector, then it will ## issue a warning and return a column vector. ## ## @end deftypefn ## Author: KH <Kurt.Hornik@ci.tuwien.ac.at> ## Created: 15 October 1994 ## Adapted-By: jwe ## 2001-10-22 Paul Kienzle ## * handle matrix inputs ## * output row vector if either input is a row vector ## 2001-10-22 Paul Kienzle ## * restore octave orientation for mismatched vectors, but issue a warning function z = cross (x, y) if (nargin != 2) usage ("cross (x, y)"); endif ## XXX COMPATIBILITY XXX opposite behaviour for cross(row,col) ## Swap x and y in the assignments below to get the matlab behaviour. ## Better yet, fix the calling code so that it uses conformant vectors. if (columns(x) == 1 && rows(y) == 1) warning ("cross: taking cross product of column by row"); y = y.'; elseif (rows(x) == 1 && columns(y) == 1) warning ("cross: taking cross product of row by column"); x = x.'; endif if (size(x) == size(y)) if (rows(x) == 3) z = [x(2,:).*y(3,:) - x(3,:).*y(2,:) x(3,:).*y(1,:) - x(1,:).*y(3,:) x(1,:).*y(2,:) - x(2,:).*y(1,:)]; elseif (columns(x) == 3) z = [x(:,2).*y(:,3) - x(:,3).*y(:,2)\ x(:,3).*y(:,1) - x(:,1).*y(:,3)\ x(:,1).*y(:,2) - x(:,2).*y(:,1)]; else error ("cross: x,y must have dimension nx3 or 3xn"); endif else error ("cross: x and y must have the same dimensions"); endif endfunction