changelog shortlog tags changeset files revisions annotate raw

scripts/general/cart2pol.m

changeset 10289: 4b124317dc38
parent:eb63fbe60fab
author: John W. Eaton <jwe@octave.org>
date: Tue Feb 09 20:58:55 2010 -0500 (51 minutes ago)
permissions: -rw-r--r--
description: base_properties::set_children: account for hidden children 
     1## Copyright (C) 2000, 2001, 2002, 2004, 2005, 2006, 2007, 2009 Kai Habel

     2##

     3## This file is part of Octave.

     4##

     5## Octave is free software; you can redistribute it and/or modify it

     6## under the terms of the GNU General Public License as published by

     7## the Free Software Foundation; either version 3 of the License, or (at

     8## your option) any later version.

     9##

    10## Octave is distributed in the hope that it will be useful, but

    11## WITHOUT ANY WARRANTY; without even the implied warranty of

    12## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    13## General Public License for more details.

    14##

    15## You should have received a copy of the GNU General Public License

    16## along with Octave; see the file COPYING.  If not, see

    17## <http://www.gnu.org/licenses/>.

    18

    19## -*- texinfo -*-

    20## @deftypefn  {Function File} {[@var{theta}, @var{r}] =} cart2pol (@var{x}, @var{y})

    21## @deftypefnx {Function File} {[@var{theta}, @var{r}, @var{z}] =} cart2pol (@var{x}, @var{y}, @var{z})

    22## Transform Cartesian to polar or cylindrical coordinates.

    23## @var{x}, @var{y} (and @var{z}) must be the same shape, or scalar.

    24## @var{theta} describes the angle relative to the positive x-axis.

    25## @var{r} is the distance to the z-axis (0, 0, z).

    26## @seealso{pol2cart, cart2sph, sph2cart}

    27## @end deftypefn

    28

    29## Author: Kai Habel <kai.habel@gmx.de>

    30## Adapted-by: jwe

    31

    32function [theta, r, z] = cart2pol (x, y, z)

    33

    34  if (nargin < 2 || nargin > 3)

    35    error ("cart2pol: number of arguments must be 2 or 3");

    36  endif

    37

    38  if (nargin == 2 && nargout > 2)

    39    error ("cart2pol: number of output arguments must not be greater than number of input arguments");

    40  endif

    41

    42  if ((ismatrix (x) && ismatrix (y) && (nargin == 2 || ismatrix (z)))

    43      && (size_equal (x, y) || isscalar (x) || isscalar (y))

    44      && (nargin == 2 || size_equal (x, z) || isscalar (x) || isscalar (z))

    45      && (nargin == 2 || size_equal (y, z) || isscalar (y) || isscalar (z)))

    46  

    47    theta = atan2 (y, x);

    48    r = sqrt (x .^ 2 + y .^ 2);

    49

    50  else

    51    error ("cart2pol: arguments must be matrices of same size, or scalar");

    52  endif

    53

    54endfunction

    55

    56%!test

    57%! x = [0, 1, 2];

    58%! y = 0;

    59%! [t, r] = cart2pol (x, y);

    60%! assert (t, [0, 0, 0]);

    61%! assert (r, x);

    62

    63%!test

    64%! x = [0, 1, 2];

    65%! y = [0, 1, 2];

    66%! [t, r] = cart2pol (x, y);

    67%! assert (t, [0, pi/4, pi/4], sqrt(eps));

    68%! assert (r, sqrt(2)*[0, 1, 2], sqrt(eps));

    69

    70%!test

    71%! x = [0, 1, 2];

    72%! y = [0, 1, 2];

    73%! z = [0, 1, 2];

    74%! [t, r, z2] = cart2pol (x, y, z);

    75%! assert (t, [0, pi/4, pi/4], sqrt(eps));

    76%! assert (r, sqrt(2)*[0, 1, 2], sqrt(eps));

    77%! assert (z, z2);

    78

    79%!test

    80%! x = [0, 1, 2];

    81%! y = 0;

    82%! z = 0;

    83%! [t, r, z2] = cart2pol (x, y, z);

    84%! assert (t, [0, 0, 0], eps);

    85%! assert (r, x, eps);

    86%! assert (z, z2);

    87

    88%!test

    89%! x = 0;

    90%! y = [0, 1, 2];

    91%! z = 0;

    92%! [t, r, z2] = cart2pol (x, y, z);

    93%! assert (t, [0, 1, 1]*pi/2, eps);

    94%! assert (r, y, eps);

    95%! assert (z, z2);

    96

    97%!test

    98%! x = 0;

    99%! y = 0;

   100%! z = [0, 1, 2];

   101%! [t, r, z2] = cart2pol (x, y, z);

   102%! assert (t, 0);

   103%! assert (r, 0);

   104%! assert (z, z2);

   105