I am working on LibSVM classifier (in java) and I want to get the alpha vector which results from the training. So, can anybody tell me how to get the alpha vector using java code?
This is a snapshot of my code:
LibSVM svm = new LibSVM();
svm.buildClassifier(train);
Evaluation evaluation = null;
evaluation = new Evaluation (train);
evaluation.crossValidateModel(svm, train, 10, new Random(1));
I am getting correct classification results as I verified that with weka GUI, but I have no idea how to get the alpha vector.
Thanks for your help.
I am not sure what you mean by "alpha vector". Maybe the following link is answering your question.
http://www.csie.ntu.edu.tw/~cjlin/libsvm/faq.html#f4151
I mean the support vectors. I have checked this link that you gave me and it doesn't answer my question.
Check the following link
http://www.csie.ntu.edu.tw/~cjlin/libsvm/faq.html#f433
Another solution: after training the classifier, you will get a .model file, the format of which is like
svm_type c_svc
nr_class 2
num_kernels 1
-t 0 -w 0.5 -u 1 -d 3 -g 0.076923076923076927 -r 0
total_sv 101
rho -1.0487135067135656
label 1 -1
nr_sv 51 50
SV
1 0:2 1:0.166667 2:1 3:-0.333333 4:-0.433962 5:-0.383562 6:-1 7:-1 8:0.0687023 9:-1 10:-0.903226 11:-1 12:-1 13:1
1 0:6 1:0.125 2:1 3:0.333333 4:-0.320755 5:-0.406393 6:1 7:1 8:0.0839695 9:1 10:-0.806452 12:-0.333333 13:0.5
The vectors after the headers, i.e. the last two lines after "SV", are supposed to be support vectors.
BTW, I am using a modified version of LibSVM, so the format of the headers is somewhat different from that of the original version.
Thank you so much, I got it. My question now: how can I get the support vectors indices in java please?
Thanks for your help,
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