clear all;
clc;
%Deklarasi Data
x1 = [2 1 0 2 0];
x2 = [3 1 3 1 0];
d1 = [17 3 9 9 0];
%Input Weight & Bias
w11 = 0.1;
w12 = -0.1;
w2 = 0;
w31 = 0;5;
w32 = -0;5;
w41 = 0.2;
w42 = 0;
w43 = -0.2;
b1 = 0.1;
b2 = 0.2;
b3 = 0.3;
b4 = 0.4;
%Iteration, Eta dan A
a = 0.8;
eta = 0.01;
iter = 5000;
%Perhitungan
for i=i:iter;
    %Perhitungan Neuron
    net1 = [w11 w12]*[x1;x2] + b1;
    y1   = 1./(1+exp(a*(-net1)));
    net2 = (x2*w2) + b2;
    y2   = 1./(1+exp(a*(-net2)));
    net3 = [w31 w32]*[x1;x2] + b3;
    y3   = 1./(1+exp(a*(-net3)));
    net4 = [w41 w42 w43]*[y1;y2;y3] + b4;
    y4   = a*net4;
    %Nilai Error
    delta1 = d1 - y4;
    %Feedback Neuron 4
    w41 = w41 + eta*a*delta1*y1';
    w42 = w42 + eta*a*delta1*y2';
    w43 = w43 + eta*a*delta1*y3';
    b4 = b4 + eta*delta1*ones(1,length(d1))';
    %Feedback Neuron 3
    w31 = w31 + eta*delta1*w43*a^2*(x1.*y3.*(1-y3))';
    w32 = w32 + eta*delta1*w43*a^2*(x2.*y2.*(1-y2))';
    b3 = b3 + eta*delta1*w43*a^2*(y3.*(1-y3))';
    %Feedback Neuron 2
    w2 = w2 + eta*delta1*w42*a^2*(x2.*y2.*(1-y2))';
    b2 = b2 + eta*delta1*w42*a^2*(y2.*(1-y2))';
    %Feedback Neuron 1
    w11 = w11 + eta*delta1*w41*a^2*(x1.*y1.*(1-y1))';
    w12 = w12 + eta*delta1*w41*a^2*(x2.*y1.*(1-y1))';
    b1 = b1 + eta*delta1*w41*a^2*(y1.*(1-y1))';
    %Cetak Iterasi
    fprintf('Iteration %i: Delta = %4.2e w11=%4.2e w12=%4.2e w2=%4.2e w31=%4.2e w32=%4.2e w41=%4.2e w42=%4.2e w43=%4.2e b1=%4.2e b2=%4.2e b3=%4.2e b4=%4.2e\r',i,sum(abs(delta1)),w11,w12,w2,w31,w32,w41,w42,w43,b1,b2,b3,b4);
end
d1;
y4;