function [dat] = ft_preproc_rectify(dat)

% FT_PREPROC_RECTIFY rectifies the data, i.e. converts all samples with a

% negative value into the similar magnitude positive value

%

% Use as

% [dat] = ft_preproc_rectify(dat)

% where

% dat data matrix (Nchans X Ntime)

%

% If the data contains NaNs, these are ignored for the computation, but

% retained in the output.

%

% See also PREPROC

% Copyright (C) 2008, Robert Oostenveld

%

% 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/>.

%

% $Id$

dat = abs(dat);