Leon Leon-Ray
Leon-Ray
/ lrCostFunction
Last active
January 31, 2022 22:40
Vectorized logistic regression with regularization using gradient descent for the Coursera course Machine Learning. Cost function (J) and partial derivatives of the cost w.r.t. each parameter in theta (grad).
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| len = size(theta); | |
| J = 1/m*(-y'*log(sigmoid(X*theta))-(1-y)'*log(1-sigmoid(X*theta))) + lambda/(2*m)*sum(theta(2:len).^2); | |
| grad = 1./m*((sigmoid(X*theta)-y)'*X); | |
| temp = theta; | |
| temp(1) = 0; | |
| grad = grad + (lambda/m.*temp)'; |