diff scripts/general/sph2cart.m @ 10688:7357e37f34fa

coordinate transforms: add option to operate on column matrix of coordinates.
author Rik <octave@nomad.inbox5.com>
date Tue, 08 Jun 2010 21:47:05 -0700
parents a8ce6bdecce5
children fd0a3ac60b0e
line wrap: on
line diff
--- a/scripts/general/sph2cart.m
+++ b/scripts/general/sph2cart.m
@@ -17,13 +17,22 @@
 ## <http://www.gnu.org/licenses/>.
 
 ## -*- texinfo -*-
-## @deftypefn {Function File} {[@var{x}, @var{y}, @var{z}] =} sph2cart (@var{theta}, @var{phi}, @var{r})
+## @deftypefn  {Function File} {[@var{x}, @var{y}, @var{z}] =} sph2cart (@var{theta}, @var{phi}, @var{r})
+## @deftypefnx {Function File} {[@var{x}, @var{y}, @var{z}] =} sph2cart (@var{S})
+## @deftypefnx {Function File} {C =} sph2cart (@dots{})
 ## Transform spherical to Cartesian coordinates.
-## @var{x}, @var{y} and @var{z} must be the same shape, or scalar.
+##
 ## @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)}.
-## @seealso{pol2cart, cart2pol, cart2sph}
+## @var{theta}, @var{phi}, and @var{r} must be the same shape, or scalar.
+## If called with a single matrix argument then each row of @var{s} 
+## represents the spherical coordinate (@var{theta}, @var{phi}, @var{r}).
+## 
+## If only a single return argument is requested then return a matrix
+## @var{C} where each row represents one Cartesian coordinate
+## (@var{x}, @var{y}, @var{z}).
+## @seealso{cart2sph, pol2cart, cart2pol}
 ## @end deftypefn
 
 ## Author: Kai Habel <kai.habel@gmx.de>
@@ -31,21 +40,33 @@
 
 function [x, y, z] = sph2cart (theta, phi, r)
 
-  if (nargin != 3)
+  if (nargin != 1 && nargin != 3)
     print_usage ();
   endif
 
-  if ((ismatrix (theta) && ismatrix (phi) && ismatrix (r))
-      && (size_equal (theta, phi) || isscalar (theta) || isscalar (phi))
-      && (size_equal (theta, r) || isscalar (theta) || isscalar (r))
-      && (size_equal (phi, r) || isscalar (phi) || isscalar (r)))
+  if (nargin == 1)
+    if (ismatrix (theta) && columns (theta) == 3)
+      r = theta(:,3);    
+      phi = theta(:,2);    
+      theta = theta(:,1);    
+    else
+      error ("sph2cart: matrix input must have 3 columns [THETA, PHI, R]");
+    endif
+  elseif (nargin == 3)
+    if (! ((ismatrix (theta) && ismatrix (phi) && ismatrix (r))
+            && (size_equal (theta, phi) || isscalar (theta) || isscalar (phi))
+            && (size_equal (theta, r) || isscalar (theta) || isscalar (r))
+            && (size_equal (phi, r) || isscalar (phi) || isscalar (r))))
+      error ("sph2cart: THETA, PHI, and R must be matrices of the same size, or scalar");
+    endif
+  endif
 
-    x = r .* cos (phi) .* cos (theta);
-    y = r .* cos (phi) .* sin (theta);
-    z = r .* sin (phi);
+  x = r .* cos (phi) .* cos (theta);
+  y = r .* cos (phi) .* sin (theta);
+  z = r .* sin (phi);
 
-  else
-    error ("sph2cart: arguments must be matrices of same size, or scalar");
+  if (nargout <= 1)
+    x = [x, y, z];
   endif
 
 endfunction
@@ -86,3 +107,8 @@
 %! assert (y, [0, 1, 0], eps);
 %! assert (z, [0, 0, 0], eps);
 
+%!test
+%! S = [ 0, 0, 1; 0.5*pi, 0, 1; pi, 0, 1];
+%! C = [ 1, 0, 0; 0, 1, 0; -1, 0, 0];
+%! assert (sph2cart(S), C, eps);
+