simpleroc.m

数据挖掘的工具箱,最新版的,希望对做这方面研究的人有用

function f = simpleroc(netout,truelab)
%SIMPLEROC Basic receiver-operating characteristic curve
%
%      F = SIMPLEROC(NETOUT,TRUELAB)
%
% Compute the ROC curve for the network output NETOUT, given the true
% labels TRUELAB. TRUELAB should contain 0-1 values, where 0 is the
% correct output if (netout < some_threshold) and 1 when the
% (netout > some_threshold).
%
% This version returns a vector of the same length as NETOUT and
% TRUELAB. Maybe this will be shortened/subsampled in the future.
%
% See also: dd_roc, plotroc

% Check the size of the netout vector:
if size(netout,2)~=1
	netout = netout';
	if size(netout,1)~=1
		error('Please make netout a column vector');
	end
end

% So all sizes become:
n = size(netout,1);
n_t = sum(truelab);
n_o = n - n_t;

% Sort the network output:
[sout,I] = sort(netout);
slab = truelab(I);

% Go over the whole range
f = zeros(n-1,2);
for i=1:n-1
	f(i,1) = sum(slab(1:i));
	f(i,2) = sum(1-slab((i+1):n));
end
% ... and normalize:
f = f./repmat([n_t n_o],n-1,1);


return