regularization

asd.m

function [J, grad] = costFunctionReg(theta, X, y, lambda)

m = length(y); % number of training examples
J = 0;
grad = zeros(size(theta));
[J, grad] = costFunction(theta, X,y);
reg = ( (sum(theta.^2) - theta(1,1)^2) * (lambda/(2*m)) )
J = J + reg;
for iter = 1:size(grad),
    if (iter) > 1,
        grad(iter) = grad(iter) + theta(iter, 1) * lambda / m;
    end
end