function [H] = scale(f)

% SCALE returns the homogenous coordinate transformation matrix
% corresponding to a scaling along the x, y and z-axis
% 
% Use as
%   [H] = translate(S)
% where
%   S   [sx, sy, sz] scaling along each of the axes
%   H   corresponding homogenous transformation matrix
%
% See also TRANSLATE, ROTATE, RIGIDBODY, QUATERNION, HOMOGENOUS2TRADITIONAL

% Copyright (C) 2000-2024, Robert Oostenveld
%
% This program 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 2 of the License, or
% (at your option) any later version.
%
% This program 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 this program; if not, write to the Free Software
% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

% This file is part of FieldTrip, see http://www.fieldtriptoolbox.org
% for the documentation and details.
%
%    FieldTrip 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.
%
%    FieldTrip 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 FieldTrip. If not, see <http://www.gnu.org/licenses/>.
%
% $Id$

if numel(f)~=3
  ft_error('incorrect input vector');
end

H = [
  f(1) 0    0    0 
  0    f(2) 0    0
  0    0    f(3) 0
  0    0    0    1
  ];

  
