%% Copyright (c) 2011, INRA
%% 2007-2011, David Legland <david.legland@grignon.inra.fr>
%% 2011 Adapted to Octave by Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
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%% -*- texinfo -*-
%% @deftypefn {Function File} {@var{vr} = } rotateVector (@var{v}, @var{theta})
%% Rotate a vector by a given angle
%%
%%  Rotate the vector @var{v} by an angle @var{theta}, given in radians.
%%
%%   Example
%%
%% @example
%%   rotateVector([1 0], pi/2)
%%   ans = 
%%       0   1
%% @end example
%%
%% @seealso{vectors2d, transformVector, createRotation}
%% @end deftypefn

function vr = rotateVector(v, angle)

  % precomputes angles
  cot = cos(angle);
  sit = sin(angle);

  % compute rotated coordinates
  vr = [cot * v(:,1) - sit * v(:,2) , sit * v(:,1) + cot * v(:,2)];
  
endfunction

%!assert ([0 1],rotateVector([1 0],pi/2), 1e-6)
%!assert (sqrt([0.5 0.5]),rotateVector([1 0],pi/4), 1e-6)