機械学習を1ヵ月で実践レベルにする #5 (線形回帰 Octave 実装) ref: http://qiita.com/junichiro/items/1a4b87e99b471cf5bea1

file0.txt

function J = computeCost(X, y, theta)
    m = length(y);
    J = 1/2/m * sum((X * theta - y).^2);
end

file1.txt

function [theta, J_history] = gradientDescent(X, y, theta, alpha, num_iters)
    m = length(y);
    for iter = 1:num_iters
        theta = theta - alpha / m * X' * (X * theta -y);
    end
end