CI 4_3

ci_4_3.m

clear all;
	
	function y_i = ForwardProp(W, T, X)
		n = length(T);
		y_i = [X, zeros(1,n-length(X))];
		for j= 3:n
			s = 0;
			for i = 1:n
				if (T(i,j) == 1)  
					s = s + W(i,j)*y_i(i);
				end;
			end;
			y_i(j) = ActivationFunc(s);
		end;
	endfunction;
	
	function x = ActivationFunc(s)
		lambda = 1;
		x = 1/(1+exp(-lambda*s));
	endfunction;
	
	function e = ErrorFunction(y_i, y)
		e = (y_i - y)^2;	
	endfunction;
	
	function f = F_(y)
		f = y*(1-y);
	endfunction;
	
	function k = deltaOutput(y, d)
		k = 2*(y-d)*F_(y);
	endfunction;
	
	function k = deltaHidden(T, W, k, y, n)
		sum = 0;
		for j = 1:length(T)
			if (T(n,j) == 1)
				sum = sum + W(n, j)*k(j);
			end;
		end;
		k = F_(y)*sum;
	endfunction;
	
	X = [ 0 0 ;
	      0 1 ;
		  1 0 ;
		  1 1];
	Y = [0; 1; 1; 0];
	
	
	y = [0 0 0 0 0 0 0];
	

	T =[0 0 1 1 1 1 0;
		0 0 1 1 1 1 0;
		0 0 0 0 0 0 1;
		0 0 0 0 0 0 1;
		0 0 0 0 0 0 1;
		0 0 0 0 0 0 1;
		0 0 0 0 0 0 0 ];
		 
	W = randn(7,7);
	
	nn = 0.9;

 	Ev = [];
	out = [];
	for limit = 1:1000000
		
		E = 0;
		for i=1:length(Y)
			n = length(T);
			y_i = ForwardProp(W, T, X(i,:));
			out(i) = y_i(n);
			e = ErrorFunction(y_i(n), Y(i));
			E = E + e;	
			
			w = [];
			k(7) = deltaOutput(y_i(7), Y(i));
			w(:,7) = k(7)*y_i;
			for i=6:-1:1
				k(i) = deltaHidden(T, W, k, y_i(i), i);
				w(:,i) = k(i)*y_i;		
			end;
			
			W = W - nn*w;
		end;
		
		Ev = [Ev, E];
		if (mod(limit, 100) == 0)
			semilogy(Ev);
			drawnow();
			printf("\nIteration %d\n", limit);
			printf("\t%d -> %f\n",  Y(1), out(1));
			printf("\t%d -> %f\n",  Y(2), out(2));
			printf("\t%d -> %f\n",  Y(3), out(3));
			printf("\t%d -> %f\n",  Y(4), out(4));
			fflush(stdout);
		end;
	end;