function [C,rate]=confmat(Y,T)%CONFMAT Compute a confusion matrix.%%	Description%	[C, RATE] = CONFMAT(Y, T) computes the confusion matrix C and%	classification performance RATE for the predictions mat{y} compared%	with the targets T.  The data is assumed to be in a 1-of-N encoding,%	unless there is just one column, when it is assumed to be a 2 class%	problem with a 0-1 encoding.  Each row of Y and T corresponds to a%	single example.%%	In the confusion matrix, the rows represent the true classes and the%	columns the predicted classes.  The vector RATE has two entries: the%	percentage of correct classifications and the total number of correct%	classifications.%%	See also%	CONFFIG, DEMTRAIN%%	Copyright (c) Ian T Nabney (1996-2001)[n c]=size(Y);[n2 c2]=size(T);if n~=n2 | c~=c2  error('Outputs and targets are different sizes')endif c > 1  % Find the winning class assuming 1-of-N encoding  [maximum Yclass] = max(Y', [], 1);  TL=[1:c]*T';else  % Assume two classes with 0-1 encoding  c = 2;  class2 = find(T > 0.5);  TL = ones(n, 1);  TL(class2) = 2;  class2 = find(Y > 0.5);  Yclass = ones(n, 1);  Yclass(class2) = 2;end% Compute correct = (Yclass==TL);total=sum(sum(correct));rate=[total*100/n total];C=zeros(c,c);for i=1:c  for j=1:c    C(i,j) = sum((Yclass==j).*(TL==i));  endend