function A2 = auroc(points,TP,FP)
% WBL 13 Sep 2002 Calculate area under convex hull of points
% $Revision: 1.5 $  $Date: 2002/10/31 11:24:40 $

xv = [0; 1; 1; points(:,2); 0];
yv = [0; 1; 0; points(:,1); 0];
%[xv yv];
%A = polyarea(xv,yv);
%plot(xv,yv); title(['Area = ' num2str(A)]); axis image
k = convhull(xv,yv);
A2 = polyarea(xv(k),yv(k));
%plot(xv(k),yv(k),'r-',points(:,2),points(:,1),'b+',FP,TP,'g+');
%title(['convhull Area = ' num2str(A2)]); axis image
%auroc(roc);
%fprintf('Area under ROC %f\n',a);

%hull =[ xv(k) yv(k)];
%plot(hull(:,1),hull(:,2),'r-',points(:,2),points(:,1),'b+');
%save('auroc','points','hull','k','A2');