lecture1机器学习by李宏毅

Regression

step1:model

y=b+w*x cp

step2:goodness of function

loss function:how bad the function is

step3:best function

令Lf最小

GRADIENT DESCENT：协助计算偏微分

lenear 无需考虑此问题

Overfitting:A more complex model does not always lead to better performance on testing data.

hidden factor->

back to step1:redesign the model

back to step2:regularizaton

越平滑，对noise越不敏感。training data误差越小，但testing data误差不一定