機械学習を1ヵ月で実践レベルにする #10 (正則化) ref: https://qiita.com/junichiro/items/8b1867201663c5af38a4

file0.txt

hx = X * theta;
cost = hx - y;
theta = [0; theta(2:end, :)];
J = ((cost' * cost) + lambda * (theta' * theta)) / (2 * m);

file1.txt

grad = (X' * cost + lambda * theta) / m;

file2.txt

J = -1/m * sum(y .* log(sigmoid(X * theta)) + (1 - y) .* log(1 - sigmoid(X * theta))) + lambda / 2 /m * sum(theta(2:end,:).^2);

file3.txt

grad = 1/m * (X' * (sigmoid(X * theta) - y)) + lambda / m * [0 ; theta(2:size(theta), :)];;

file4.txt

grad = 1/m * (X' * (sigmoid(X * theta) - y)) + lambda / m * [0 ; theta(2:size(theta), :)];;