binarylabels.m.svn-base

a function inside machine learning

function bl = binaryLabels(Y)

% A function to test whether Y has binary labels. Returns 
% 0 for non-binary, 1 for (-1, +1) and 2 for (0, +1)  
%
% Usage: bl = binaryLabels(Y)
% Inputs/Outputs: 
%   Y - an (l x n) matrix whose rows are labels
%
%   bl - 0 for non-binary, 1 for (-1, +1) and 2 for (0, +1)  
%
% Copyright (C) 2006 Charanpal Dhanjal 

% This library is free software; you can redistribute it and/or
% modify it under the terms of the GNU Lesser General Public
% License as published by the Free Software Foundation; either
% version 2.1 of the License, or (at your option) any later version.
% 
% This library 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
% Lesser General Public License for more details.
% 
% You should have received a copy of the GNU Lesser General Public
% License along with this library; if not, write to the Free Software
% Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301
% USA

if (nargin ~= 1)
    fprintf('%s\n', help(sprintf('%s', mfilename)));
    error('Incorrect number of inputs - see above usage instructions.');
end

numExamples = size(Y, 1); 
numLabels = size(Y, 2); 

bl = sum(sum(Y == -1 | Y == 1)) == numExamples*numLabels; 

if bl == 0 
    bl = (sum(sum(Y == 0 | Y == 1)) == numExamples*numLabels)*2; 
end