Mercurial > octave
view scripts/general/cart2sph.m @ 21178:3be6a07e8bad
maint: Periodic merge of stable to default.
author | John W. Eaton <jwe@octave.org> |
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date | Tue, 02 Feb 2016 17:06:11 -0500 |
parents | 516bb87ea72e 5f62b5dae8b1 |
children | 1e88747417e6 |
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## Copyright (C) 2000-2016 Kai Habel ## ## This file is part of Octave. ## ## Octave 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. ## ## Octave 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 Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {} {[@var{theta}, @var{phi}, @var{r}] =} cart2sph (@var{x}, @var{y}, @var{z}) ## @deftypefnx {} {[@var{theta}, @var{phi}, @var{r}] =} cart2sph (@var{C}) ## @deftypefnx {} {@var{S} =} cart2sph (@dots{}) ## Transform Cartesian coordinates to spherical coordinates. ## ## The inputs @var{x}, @var{y}, and @var{z} must be the same shape, or scalar. ## If called with a single matrix argument then each row of @var{C} represents ## the Cartesian coordinate (@var{x}, @var{y}, @var{z}). ## ## @var{theta} describes the angle relative to the positive x-axis. ## ## @var{phi} is the angle relative to the xy-plane. ## ## @var{r} is the distance to the origin @w{(0, 0, 0)}. ## ## If only a single return argument is requested then return a matrix @var{S} ## where each row represents one spherical coordinate ## (@var{theta}, @var{phi}, @var{r}). ## @seealso{sph2cart, cart2pol, pol2cart} ## @end deftypefn ## Author: Kai Habel <kai.habel@gmx.de> ## Adapted-by: jwe function [theta, phi, r] = cart2sph (x, y, z) if (nargin != 1 && nargin != 3) print_usage (); endif if (nargin == 1) if (! (isnumeric (x) && ismatrix (x) && columns (x) == 3)) error ("cart2sph: matrix input must have 3 columns [X, Y, Z]"); endif z = x(:,3); y = x(:,2); x = x(:,1); else if (! ((isnumeric (x) && isnumeric (y) && isnumeric (z)) && (size_equal (x, y) || isscalar (x) || isscalar (y)) && (size_equal (x, z) || isscalar (x) || isscalar (z)) && (size_equal (y, z) || isscalar (y) || isscalar (z)))) error ("cart2sph: X, Y, Z must be numeric arrays of the same size, or scalar"); endif endif theta = atan2 (y, x); phi = atan2 (z, sqrt (x .^ 2 + y .^ 2)); r = sqrt (x .^ 2 + y .^ 2 + z .^ 2); if (nargout <= 1) theta = [theta(:), phi(:), r(:)]; endif endfunction %!test %! x = [0, 1, 2]; %! y = [0, 1, 2]; %! z = [0, 1, 2]; %! [t, p, r] = cart2sph (x, y, z); %! assert (t, [0, pi/4, pi/4], eps); %! assert (p, [0, 1, 1]*atan (sqrt (0.5)), eps); %! assert (r, [0, 1, 2]*sqrt (3), eps); %!test %! x = 0; %! y = [0, 1, 2]; %! z = [0, 1, 2]; %! S = cart2sph (x, y, z); %! assert (S(:,1), [0; 1; 1] * pi/2, eps); %! assert (S(:,2), [0; 1; 1] * pi/4, eps); %! assert (S(:,3), [0; 1; 2] * sqrt (2), eps); %!test %! x = [0, 1, 2]; %! y = 0; %! z = [0, 1, 2]; %! [t, p, r] = cart2sph (x, y, z); %! assert (t, [0, 0, 0]); %! assert (p, [0, 1, 1] * pi/4); %! assert (r, [0, 1, 2] * sqrt (2)); %!test %! x = [0, 1, 2]; %! y = [0, 1, 2]; %! z = 0; %! [t, p, r] = cart2sph (x, y, z); %! assert (t, [0, 1, 1] * pi/4); %! assert (p, [0, 0, 0]); %! assert (r, [0, 1, 2] * sqrt (2)); %!test %! C = [0, 0, 0; 1, 0, 1; 2, 0, 2]; %! S = [0, 0, 0; 0, pi/4, sqrt(2); 0, pi/4, 2*sqrt(2)]; %! assert (cart2sph (C), S, eps); %!test %! [x, y, z] = meshgrid ([0, 1], [0, 1], [0, 1]); %! [t, p, r] = cart2sph (x, y, z); %! T(:, :, 1) = [0, 0; pi/2, pi/4]; %! T(:, :, 2) = T(:, :, 1); %! P(:, :, 1) = zeros (2, 2); %! P(:, :, 2) = [pi/2, pi/4; pi/4, acos(sqrt(2/3))]; %! R = sqrt (x .^ 2 + y .^ 2 + z .^ 2); %! assert (t, T, eps); %! assert (p, P, eps); %! assert (r, R, eps); ## Test input validation %!error cart2sph () %!error cart2sph (1,2) %!error cart2sph (1,2,3,4) %!error <matrix input must have 3 columns> cart2sph ({1,2,3}) %!error <matrix input must have 3 columns> cart2sph (ones (3,3,2)) %!error <matrix input must have 3 columns> cart2sph ([1,2,3,4]) %!error <numeric arrays of the same size> cart2sph ({1,2,3}, [1,2,3], [1,2,3]) %!error <numeric arrays of the same size> cart2sph ([1,2,3], {1,2,3}, [1,2,3]) %!error <numeric arrays of the same size> cart2sph ([1,2,3], [1,2,3], {1,2,3}) %!error <numeric arrays of the same size> cart2sph (ones (3,3,3), 1, ones (3,2,3)) %!error <numeric arrays of the same size> cart2sph (ones (3,3,3), ones (3,2,3), 1)