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@ -40,7 +40,9 @@ Theta_grad = zeros(size(Theta));
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% partial derivatives w.r.t. to each element of Theta
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%
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J = 0.5 * sum(sum(R.*(X*Theta'-Y).^2));
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J = 0.5 * sum(sum(R.*(X*Theta'-Y).^2)) ...
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+ 0.5 * lambda * sum(sum(Theta.^2)) ...
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+ 0.5 * lambda * sum(sum(X.^2));
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X_grad = (R.*(X*Theta'-Y))*Theta; % mov X user * uxer X feat = mov X feat
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Theta_grad = (R.*(X*Theta'-Y))'*X; % user X mov * mov X feat = user X feat
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