svm - LibSVM one class classification nu parameter is not a fraction of outliers? -


Please correct me if I am wrong, but a class SVM principle states that nu parameter upper bound (UB) training Outliers in Datasets and LBs of the number of SVs say that I am using RBF Gaussian Kernel, so considering the nu parameter, no matter what the value of gamma I choose, the result of the model Be able to generate Is there a UB outlayer dataset in parameter NU training? However, it is not what I have seen that I have seen using a few simple examples with LbsM in Little:

  [heart_scale_label, heart_scale_inst] = libsvmread ('.. / heart_scale') ; Ind_good = (heart_scale_label == 1); Heart_scale_label = heart_scale_label (ind_good); Heart_scale_inst = heart_scale_inst (ind_good); Train_data = heart_scale_inst; Train_label = heart_scale_label; Gamma = 0.01; New = 0.01; Model = svmtrain (train_label, train_data, ['-s 2 -t 2 -n' num2str (nu) '-g' num2str (gamma) '-h 0']); [Predict_label_Tr, accuracy_tr, dec_values_Tr] = svmpredict (train_label, train_data, model); Accuracy by using Gamma = 0.01 TAGR = <0.01> I get the accuracy of trained data using 97.50 / gamma = 100. I get the accuracy of training data as 42.50 only when the only part of the outliers in training dataset, Is selected?   

Actually I discovered the same problem. The performance of SVM generally depends on the contact of γ and nu. If you are fixing a parameter while trying to tune each other, then there is not even one in the learning curve.

I have to draw training accuracy, accuracy test (5 times in depth of heart), and three images on their difference. From γ to 10 ^ (- 4) to 10 ^ (1) , and nu from 10 ^ (- 3) to to < Code> 10 ^ (- 1) :

enter image details here

To observe the small parameters more clearly, I applied logarithm to γ and New axis, see the following figure:

 Enter image details here

In fact, looks more clearly than with the given 120 data.

 Enter the image details here

Not quite clear or not perfect at all! Generalization on parameters seems a bit smoother as the dependence of the error, possibly due to the optimization algorithm used in Libsevim instead of 'true' solution ...

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