function [ITr2 ITe2 NFS] = fs3(P, PT, T, th)

% Feature Selector function 3 (irrelevant to 1 & 2). It is based on IDND3. Selects using harmean of IDs as threshold.
% Requirements: ID3.m

% Copyright by Zack Voulgaris, London, March - September 2007

sT = size(T);
[N ind] = max(sT); % Number of elements
[r na] = size(P);

if r ~= N
    error('Dimensionality of Input and Output do not match!')
end

[r c] = size(PT);
if c ~= na
    error('Dimensionality of Input and Output do not match!')
end

if sT(3-ind) ~= 1
    error('Target Training must be a vector')
end

p(na) = 0;
for i = 1:na
    p(i) = ID3(P(:,i),T);
end

if nargin < 4
    th = harmean(p,2,eps);
end
     
NFS = find(p>=th);
ITr2 = P(:,NFS);
ITe2 = PT(:,NFS);