Machine Learning Field of study that gives computers the ability to learn without being explicitly programmed.A computer program is said to learn from experience E with respect to some task T and some performance measure P if it s performance on T as measured by P improves with experience E.机器学习是一个高度跨学科的研究领域find learning algorithm to problems in computer vision biology robots language文字识别信用评估网站的个性化推荐若m很大batch gradient descent每前进一步点运行代价很大stochastic gradien