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scripts/general/pol2cart.m

changeset 10289: 4b124317dc38
parent:eb63fbe60fab
author: John W. Eaton <jwe@octave.org>
date: Tue Feb 09 20:58:55 2010 -0500 (44 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{x}, @var{y}] =} pol2cart (@var{theta}, @var{r})

    21## @deftypefnx {Function File} {[@var{x}, @var{y}, @var{z}] =} pol2cart (@var{theta}, @var{r}, @var{z})

    22## Transform polar or cylindrical to Cartesian coordinates.

    23## @var{theta}, @var{r} (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{cart2pol, cart2sph, sph2cart}

    27## @end deftypefn

    28

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

    30## Adapted-by: jwe

    31

    32function [x, y, z] = pol2cart (theta, r, z)

    33

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

    35    error ("pol2cart: number of arguments must be 2 or 3");

    36  endif

    37

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

    39    error ("pol2cart: number of output arguments must not be greater than number of input arguments");

    40  endif

    41

    42   if ((ismatrix (theta) && ismatrix (r) && (nargin == 2 || ismatrix (z)))

    43       && (size_equal (theta, r) || isscalar (theta) || isscalar (r))

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

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

    46

    47    x = cos (theta) .* r;

    48    y = sin (theta) .* r;

    49

    50  else

    51    error ("pol2cart: arguments must be matrices of same size, or scalar");

    52  endif

    53

    54endfunction

    55

    56%!test

    57%! t = [0, 0.5, 1] * pi;

    58%! r = 1;

    59%! [x, y] = pol2cart (t, r);

    60%! assert (x, [1, 0, -1], sqrt(eps));

    61%! assert (y, [0, 1,  0], sqrt(eps));

    62

    63%!test

    64%! t = [0, 1, 1] * pi/4;

    65%! r = sqrt(2) * [0, 1, 2];

    66%! [x, y] = pol2cart (t, r);

    67%! assert (x, [0, 1, 2], sqrt(eps));

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

    69

    70%!test

    71%! t = [0, 1, 1] * pi/4;

    72%! r = sqrt(2) * [0, 1, 2];

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

    74%! [x, y, z2] = pol2cart (t, r, z);

    75%! assert (x, [0, 1, 2], sqrt(eps));

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

    77%! assert (z, z2);

    78

    79%!test

    80%! t = 0;

    81%! r = [0, 1, 2];

    82%! z = [0, 1, 2];

    83%! [x, y, z2] = pol2cart (t, r, z);

    84%! assert (x, [0, 1, 2], sqrt(eps));

    85%! assert (y, [0, 0, 0], sqrt(eps));

    86%! assert (z, z2);

    87

    88%!test

    89%! t = [1, 1, 1]*pi/4;

    90%! r = 1;

    91%! z = [0, 1, 2];

    92%! [x, y, z2] = pol2cart (t, r, z);

    93%! assert (x, [1, 1, 1] / sqrt(2), eps);

    94%! assert (y, [1, 1, 1] / sqrt(2), eps);

    95%! assert (z, z2);

    96

    97%!test

    98%! t = 0;

    99%! r = [1, 2, 3];

   100%! z = 1;

   101%! [x, y, z2] = pol2cart (t, r, z);

   102%! assert (x, [1, 2, 3], eps);

   103%! assert (y, [0, 0, 0] / sqrt(2), eps);

   104%! assert (z, z2);

   105