%% ROCDEMO - demonstrate use of ROC tools%%    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.%%    [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 : AUROC, ROC, ROCCH%% File        : rocdemo.m%% Date        : Wednesdaay 11th November 2004 %% Author      : Dr Gavin C. Cawley%% Description : Demonstration program/minimal test harness for a small%               collection of tools for generating Receiver Operating%               Characteristic (ROC) curves.  See [1] for further details.%% 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     : 10/11/2004 - v1.00%% 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%% start from a clean slateclear all% generate test data from Fawcett [1] (fig 3)fprintf(1, 'generating test data...\n');t = [1 1 0 1 1 1 0 0 1 0 1 0 1 0 0 0 1 0 1 0]';y = [.9  .8  .7  .6  .55 .54 .53 .52 .51 .505 ...     .4  .39 .38 .37 .36 .35 .34 .33 .3 .1]';% generate an ROC curve and plot itfprintf(1, 'plotting ROC curve...\n');[tp,fp] = roc(t,y);figure(1);clf;plot(fp,tp);xlabel('false positive rate');ylabel('true positive rate');title('ROC curve');% compute the area under the ROCfprintf(1, 'AUROC   = %f\n', auroc(tp,fp));% compute the ROC convex hull (ROCCH) curveif 1   fprintf(1, 'plotting ROCCH curve...\n');   [tp,fp] = rocch(t,y);   hold on   plot(fp, tp, 'r--');   hold off   xlabel('false positive rate');   ylabel('true positive rate');   title('ROC and ROCCH curve');   % compute the area under the ROCCH   fprintf(1, 'AUROCCH = %f\n', auroc(tp,fp));end% bye bye...