function [P2 T2 A] = PR(P,T,th)

% Pattern Reduction

if nargin < 3
    th = .25;
end

% R = 10000000; % repeating ID calculation parameter
[N na] = size(P);
n = round(N * th);

[T ind] = sort(T);
P = P(ind,:);
Q = [T(1) nan nan nan nan nan nan nan nan nan];
q = 1;
class{20} = []; c(20) = 0; cc(20) = 0;
temp = T;

for i = 1:inf
    ff = (1:N)'.*(temp == Q(q));
    f = ff(ff>0);
    c(q) = length(f); cc(q) = cc(q) + c(q);
    class{q} = [class{q};f];
    temp(f) = NaN;      
    if sum(isnan(temp))==N
        break
    end
    q = q + 1;
    Q(q) = temp(cc(q-1)+1);
    cc(q) = cc(q-1) + cc(q);
end

Q = Q(1:q);
a = [1 (cc(1:(q-1))+1)];
A(n,2) = 0; % Matrix showing patterns to be discarded
D(N,N) = 0; % Distance matrix of dataset
ad(q) = 0; % Average distance of class

for i = 1:q
    d = dmatrix3(P(class{i},:));
    ad(i) = sum(sum(d))/(c(i)*(c(i)-1));
    D(a(i):cc(i),a(i):cc(i)) = d / ad(i);
end

[z Z] = IDND5(P,T);
DD(q,N) = 0; % Minimum distance

for i = 1:q
    [M ind] = max(Z(class{i}));
    A(i,1) = ind + a(i) - 1;
    A(i,2) = i;
    Z(A(i,1)) = 0;
    DD(i,:) = D(A(i,1),:);
end

v(q,N) = 0;

for i = (q+1):n
%     p = round(100*i/n);
%     if mod(i,R) == 0
%         clc,disp(p)
%         temp = A((A(:,1)>0),1);
%         P1 = P; T1 = T;
%         P1(temp,:) = rm(inf,length(temp),na);
%         [z Z] = IDND5(P1,T1);
%         Z(temp) = 0;
%     end
    
    for j = 1:q
        v(j,:) = DD(j,:).*Z;
    end
    
    [M r c] = mmax(v); % r = class, c = pattern
    Z(c) = 0;
    A(i,:) = [c r];
    DD(r,:) = min(DD(r,:),D(A(i,1),:));
end

% p = 100;clc,disp(p)

P(A(:,1),:) = []; T(A(:,1)) = [];
P2 = P; T2 = T;