randselect.m

一种新的人脸识别算法程序

function [index1,index2] = randselect(weights)
% WBL 22 Sept 2002 To boost ANN, based on time.h r1.9
% $Revision: 1.3 $  $Date: 2002/09/25 19:27:44 $

%WBL 25 Sep 2002 yeild two separate indexes.
%                Remove in and B. They are done outside.

%rand('state',0);

ntests = size(weights,2);

%create wheel
wheel = zeros(ntests,1);
wheel(1) = weights(1);
for i=2:ntests
    wheel(i) = weights(i)+wheel(i-1);
end

u = zeros(ntests,1);
t1 = 0;
t2 = 0;
for t=1:ntests %select randomly ntests using wheel
    r = wheel(ntests)*rand;
    %Binary chop
    bot = 1; 
    top = ntests;
	while (wheel(bot)<r & top>=bot)
    	i = floor((top+bot)/2);
	    if(r < wheel(i)) top = i - 1;
	    else             bot = i + 1;
        end
	end%while
    %bot
	if(u(bot)==0) %test 'bot' not assigned choose index1 or index2
        if(t1<=t2)
            u(bot) = 1;
        else
            u(bot) = -1;
        end
    end%if new test
	if(u(bot)==1)
        t1 = t1 + 1;
        index1(t1) = bot;
    else
        t2 = t2 + 1;
        index2(t2) = bot;
    end
end