function A = auroc(tp, fp)%% AUROC - area under ROC curve%%    An ROC (receiver operator characteristic) curve is a plot of the true%    positive rate as a function of the false positive rate of a classifier%    system.  The area under the ROC curve is a reasonable performance%    statistic for classifier systems assuming no knowledge of the true ratio%    of misclassification costs.%%    A = AUROC(TP, FP) computes the area under the ROC curve, where TP and FP%    are column vectors defining the ROC or ROCCH curve of a classifier%    system.%%    [1] Fawcett, T., "ROC graphs : Notes and practical%        considerations for researchers", Technical report, HP%        Laboratories, MS 1143, 1501 Page Mill Road, Palo Alto%        CA 94304, USA, April 2004.%%    See also : ROC, ROCCH%% File        : auroc.m%% Date        : Wednesdaay 11th November 2004 %% Author      : Dr Gavin C. Cawley%% Description : Calculate the area under the ROC curve for a two-class%               probabilistic classifier.%% References  : [1] Fawcett, T., "ROC graphs : Notes and practical%                   considerations for researchers", Technical report, HP%                   Laboratories, MS 1143, 1501 Page Mill Road, Palo Alto%                   CA 94304, USA, April 2004.%% History     : 22/03/2001 - v1.00%               10/11/2004 - v1.01 minor improvements to comments etc.%% Copyright   : (c) G. C. Cawley, November 2004.%%    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 2 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, write to the Free Software%    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA%n = size(tp, 1);A = sum((fp(2:n) - fp(1:n-1)).*(tp(2:n)+tp(1:n-1)))/2;% bye bye...