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Questions tagged [libsvm]

The tag has no usage guidance, but it has a tag wiki.

1
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0answers
14 views

Practical examples/tutorials of using One-Class Support Vector Machines

I am a newbie in machine learning, and hope to solve an anomaly detection task using One-Class Support Vector Machines (OCSVM). ...
0
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1answer
42 views

Linear SVM in matlab and python giving different results

I have a particular dataset on which I am getting different results when using a linear SVM in matlab and sklearn toolbox. The data has been normalized in matlab and imported into python from a mat ...
2
votes
1answer
453 views

Why Liblinear performs drastically better than libsvm linear kernel?

l have a dataset of dim=(200,2000) 200 examples and 2000 features. l have 10 classes. l used sklearn for both cases : svm.svc(kernel=linear) LinearSVC() ...
2
votes
1answer
1k views

What is the difference between Linear SVM and SVM with linear kernel

l'm wondering whther there is a difference bewteen Linear SVM and SVM with linear kernel. Or a linear SVM is just an SVM with linear kernel ? If so what this difference between the two variables ...
0
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0answers
150 views

What is the difference in the formulation of Least Square SVM (LS-SVM) and Kernel Ridge Regression (KRR)?

I have gone through the Least-Square SVM (LS-SVM) formulation and Kernel Ridge Regression (KRR) but not able to find any significant difference between them. In some of the papers, LS-SVM just used ...
-2
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1answer
2k views

Where can I find python code for SVM that use multiple feature data? [closed]

I am trying do an Image Classification where each sample of training data contains data of the current pixel with the 8 surrounding ones. Where can I find examples of SVM, in python, that use 5 or ...
1
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0answers
42 views

Obtain standard deviation for libsvm

I have the following code for Grid search, but it only return the accuracy result using 5 folds cross-validation. Is it possible to obtain standard deviation from the 5 folds CV. How would you do that?...
0
votes
2answers
1k views

Is standardization needed before using scikit-learn SVM?

I am using the SVM function provided by scikit-learn. I would like to know whether I need to perform standardization before fitting the model. As I know, LibSVM ...
1
vote
0answers
81 views

$\chi^{2}$ kernel SVM performance issue

I am using $\chi^{2}$ kernel for non-linear SVM (using libSVM) for classifying MNIST digits. I am getting very bad performance (worse than random guessing). The $\chi^{2}$ kernel code (in MATLAB) is ...
1
vote
2answers
119 views

Prepare data for SVM, Is it valid to normalise the data before and after PCA dimension reduction

Is it valid to normalise a dataset, reduce dimensionality with PCA and then to normalise the reduced dimension data. Assuming this is performed on training data, should the same PCA coefficients be ...
0
votes
2answers
421 views

Understanding text conversion into SVM input [closed]

In Support Vector Machines, when used for sentiment analysis, text gets converted into a set of data points. How does this happen, usually?
18
votes
2answers
333 views

Use liblinear on big data for semantic analysis

I use Libsvm to train data and predict classification on semantic analysis problem. But it has a performance issue on large-scale data, because semantic analysis concerns n-dimension problem. Last ...