1. optimization objection (优化目标)
1.1 SVM hypothesis:
- cost1 与 cost0 均为代价函数;
- 左图用于正样本,右图适用于负样本;
- SVM / large margin classifier:用较大间距将样本区分开;
- 大间距分类器;
- 若 number of features >> number of training examples,则使用 logistic regression, or SVM without a kernel(linear kernel);
若 number of features < number of training examples,则使用 SVM with Gaussian kernel;
若 number of features < number of training examples,则 create/add more features, then use logistic regression or SVM without a kernel;
refenence: 《machine learning》Andrew Ng