--- /dev/null
+function r = spearman(x,y)
+% SPEARMAN Spearman's rank correlation coefficient.
+% This function is replaced by CORRCOEF.
+% Significance test and confidence intervals can be obtained from CORRCOEF.
+%
+% [R,p,ci1,ci2] = CORRCOEF(x, [y, ] 'Rank');
+%
+% For some (unknown) reason, in previous versions Spearman's rank correlation
+% r = corrcoef(ranks(x)).
+% But according to [1], Spearman's correlation is defined as
+% r = 1-6*sum((ranks(x)-ranks(y)).^2)/(N*(N*N-1))
+% The results are different. Here, the later version is implemented.
+%
+% see also: CORRCOEF, RANKCORR
+%
+% REFERENCES:
+% [1] http://mathworld.wolfram.com/SpearmanRankCorrelationCoefficient.html
+% [2] http://mathworld.wolfram.com/CorrelationCoefficient.html
+
+% $Id: spearman.m 8223 2011-04-20 09:16:06Z schloegl $
+% Copyright (C) 2000-2002 by Alois Schloegl <alois.schloegl@gmail.com>
+% This function is part of the NaN-toolbox
+% http://pub.ist.ac.at/~schloegl/matlab/NaN/
+
+% 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 3 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, see <http://www.gnu.org/licenses/>.
+
+
+% warning('SPEARMAN might become obsolete; use CORRCOEF(...,''Spearman'') instead');
+
+if nargin < 2
+ r = corrcoef(x,'Spearman');
+else
+ r = corrcoef(x,y,'Spearman');
+end