2012年10月25日

SVM(2)--Linear Nonseparable

摘要: 左边的是线性可分的(Separable),margin = 2M = 2/||w||,右边的是线性不可分(Nonseparable),其中标有 ξ 的点是在它们边界的另一边(未正确区分的点),离边界 ξ∗j = Mξj 。所有正确可分的点有 ξ∗j = 0. 因此 ∑ ξ∗j 就是所有未正确区分点偏离距离,我们在最大化margin时要限制 ∑ ξ∗j ≤ constant C.我们用soft margin(a decision boundary that is tolerable to small training errors),这个margin需要权衡margin的大小和允许错误区分点的个 阅读全文

posted @ 2012-10-25 21:23 liangzh123 阅读(294) 评论(0) 推荐(0)

SVM(1)--Linear separable

摘要: Our training data consists of m tuples (x(1), y(1)), (x(2), y(2)), . . . , (x(m), y(m)), where x(i) = (x(i1), x(i2), …,x(id))T and y(i) ∈ {−1, 1},denote the class label. The hyperplane(decision boundary) of a linear classifier can be written in the following form: wTx + b = 0, where w and b are para 阅读全文

posted @ 2012-10-25 15:03 liangzh123 阅读(362) 评论(0) 推荐(0)

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