%INVSIGM Inverse sigmoid map% % 	W = W*INVSIGM% 	B = INVSIGM(ARG)%% INPUT%	ARG   Mapping/Dataset%% OUTPUT%	W     Mapping transforming posterior probabilities into distances.%% DESCRIPTION% The inverse sigmoidal transformation to transform a classifier to a% mapping, transforming posterior probabilities into distances.%% SEE ALSO% MAPPINGS, DATASETS, CLASSC, SIGM% Copyright: R.P.W. Duin, duin@ph.tn.tudelft.nl% Faculty of Applied Sciences, Delft University of Technology% P.O. Box 5046, 2600 GA Delft, The Netherlands% $Id: invsigm.m,v 1.3 2007/03/22 08:54:59 duin Exp $function w = invsigm(arg)		prtrace(mfilename);if nargin == 0	% Create an empty mapping:	w = mapping('invsigm','combiner');	w = setname(w,'Inverse Sigmoidal Mapping');	elseif isa(arg,'mapping')	% If the mapping requested a SIGM transformation (out_conv=1), it	% is now removed (out_conv=0):	if arg.out_conv == 1		w = set(arg,'out_conv',0);		if arg.size_out == 2			w.size_out = 1;			w.labels = w.labels(1,:);			data.rot = w.data.rot(:,1);			data.offset = w.data.offset(1);			data.lablist_in = w.data.lablist_in;			w.data = data;		end	else		w_s = setname(mapping('invsigm','fixed'),'Inverse Sigmoidal Mapping');		w = arg*w_s;	end	else	% The data is really transformed:	if isdatafile(arg)		w = addpostproc(arg,invsigm);	else  % datasets and doubles		w = log(arg+realmin) - log(1-arg+realmin);	endendreturn