LIBSVM is an integrated software library for support vector machines, performing support vector classification, (C-SVC, nu-SVC), regression (epsilon-SVR, nu-SVR) and distribution estimation (one-class SVM)

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Null exception in configuration and use of LibSVM and Weka in Java code [on hold]

I have been using Weka J48 and NaiveBayesMultinomial classifiers in Java code of my own but I'm now having an issue with LibSVM. My test program's basic code, wrapped in a ...
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2answers
54 views

Assigning even partitions for Cross-Validation

This is a very basic question about cross-validation. Say that I have a sample size of 2901(or any difficult to divide number). How do I split this up into equal partitions (other than n=1)? And how ...
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3answers
32 views

Kernel selection using SVM for keyword frequency classification

I have data in Weka .arff multiple-class training and testing data representing daily word frequencies in RSS feeds as follows: ...
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31 views

Interpretation C value in linear SVM

My C value is very low (close to 0). Does this mean that my feature (dimensions) have no real separative (and thus predictive) value? (As the SVM basically chooses to ignore the training data ...
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1answer
55 views

Simple SVM Question

For a linear SVM, the documentation tells me the formula is: $$ \frac{1}{2}w^Tw+C\sum\limits_{i=1}^l\xi_i$$ Please explain to me in layman's terms what w (and ΞΎ) represent. Is w the distance to the ...
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Different Scoring with libsvm

I have been using libsvm for binary classification, e.g. given data $(x_1,\dots,x_n)$ and labels $(y_1,\dots,y_n)$ where $y_i\in\{0,1\}$. Now I am wondering if the prediction of my model can be tuned ...
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1answer
34 views

SVM cost parameter

In a SVM with linear kernel, could you explain to me what exactly the C parameter is/represents? An example why it's important to select a good value for C would also be appreciated. Thank you.
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22 views

Cross Validated Squared Correlation Coefficient in SVM regression

I am applying SVM regression on a data set on "Karthikeyan Melting Point Dataset" present here. I am using LIBSVM for it. After applying regression LIBSVM returns the cross validated squared ...
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27 views

Using LibSVM regression to predict dependent variable

My intention is to use SVR with 1-10 independent variables to best predict a dependent variable. After separating the data into scaled training and testing files containing the independent variables ...
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1answer
14 views

How to increase a particular terms's weightage?

I am doing Text classification using LibSVM in Rapid Miner. I am using TFIDF values for processing documents. I need to Increase weightage of some terms in the documents(for eg. words in BOLD and ...
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49 views

Extracting decision function variable from libsvm

I'm trying to use LIBSVM's single class SVMs for some classification and need to extract the following sum post classification (i.e. the variable that the decision function takes in) $$ ...
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26 views

One vs All appraoch to multiclassification in LIBSVM

I'm working on multiclass classification problem (precisely 4 classes). I want to use the most simple approach for this problem: one-vs-all! I have 4 different test set (only labels are different). ...
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2answers
68 views

Plotting the decision boundary of a kernel SVM (RBF)

Suppose we are given a training set of 2D points that are linearly non-separable. I train a binary SVM with an RBF kernel in order to classify them. What I want to do is to draw the desicion boundary. ...
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25 views

STRING KERNELS FOR LIBSVM

I'm working on a protein classification problem and i'm using edit distance kernel defined in libSVM. Now, for instance, the implementation of spectrum kernel is very difficult, but i want try to test ...
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31 views

Evolution strategies in libsvm

I'm working on protein multi-classification problem. I'm using libsvm and the edit distance kernel. This kernel depends from a parameter (gamma). I'm able to get the best parameters (gamma and C) ...
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23 views

Cross validation and accuracy calculation in lib-linear

I have two questions related to cross validation in LIBLINEAR I have 1000 documents from which i take 300 documents for training and rest 700 for classification . I train 300 documents with ...
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22 views

Different results in libsvm and R for regression prediction

i use e1071 package in R for SVM regression prediction and tried the same test in C# libsvm and got different results. All the parameters (gamma,cost,eps) are the same and so is the scaling method. ...
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1answer
29 views

LIBSVM RBF kernel time complexity

Is it known what is the LIBSVM time complexity when using RBF kernel functions?
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17 views

LIBSVM not Perfoming well in weka as opposed to other algorithms

I do have an issue with libSvm Weka which i feel it is very weird However, when i tried it with other algorithms such as naive bayes and j48, it achieved a high accuracy of 78%. Moreover, the same ...
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38 views

LIBSVM evaluation functions for probability estimation

I found this tool that is providing some well known evaluation functions like precision and recall. Unfortunately this tool supports only binary-class C-SVM. I was wondering where I can find similar ...
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libSVM can do external validation?

There is an option for libSVM do an external validation (external data) like for cross validation (-v mode) ? Thanks. Andre
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Training a multiclass SVM

I am using Support Vecotr Machine(SVM) with 4 Class. My corpus contain 185 documents with 4 different subjects. For each subject I defined a profile with 3 or 4 keywords (of course they are separated ...
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27 views

All positive labels when libsvm classifier is used in MATLAB

I have written a binary classification in MATLAB, using libsvm. The code is the following: ...
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61 views

Set up a classification experiment via libsvm (MATLAB)

I would like to set up an experiment in MATLAB, to predict the class of a set of text instances in a two-class problem (e.g., the text talks/does not talk about ...
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1answer
122 views

Choosing correct C and g parameters for libsvm

libsvm 3.18 Features: 10 I have used following, parameter range: ...
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76 views

LIBSVM overfitting

I trained two svms (LIBSVM) with 15451 samples after I did a 10-fold cross-validation and found the best parameter values for gamma and C (RBF kernel). In one svm I used just 1 feature and in the ...
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1answer
77 views

One class classifier Cross validation

I am working on a problem which requires one-class classifier. I am using LIBSVM. I know there are tons of material out there but still I could not find the answer to my query. How do I estimate the ...
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72 views

How to analyze plot from libsvm grid-search

I am trying to learn to use libsvm, I have used some defalut training sets to generate the plots by grid-search and obtained a plot below. I want to know, What type of plot is this, What does it ...
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32 views

Effect of high number of support vectors

I am doing Rainfall-Runoff modeling. I have 4014 inputs and 4014 outputs. I am confused about the of support vectors. Suppose I have a model having 2000 support vectors and I have another model having ...
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65 views

Accuracy changes with permutation of input data in Libsvm with precomputed kernel?

I'm doing quite simple SVM classification at the moment. I use a precomputed kernel in LibSVM with RBF and DTW. When I compute the similarity (kernel-) matrix, everything seems to work very fine ... ...
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14 views

Support Vector Machines…||w||, support vector coefficients, etc

I'm working with LibSVM and Matlab but am running into some issues. Specifically, I think I'm misunderstanding some theory. I've read here and there about the support vector coefficients, but I ...
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78 views

LIBSVM cross-validation - number of folds vs. sample size

I am using LIBSVM for classification and the default RBF Kernel. To get optimal parameters for C and gamma, I am using the grid.py tool included in the LIBSVM package. It is based on a k-fold ...
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38 views

SVM classifier - grid search on C and gamma no affect

I'm working to find the best C and gamma values for the RBF on my dataset using an SVM classifier. Specifically, I'm using LibSVM & MATLAB. ...
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110 views

Matlab - nu-support vector regression with LibSVM

I've 2 problems when applying $\nu$-SVR with LibSVM in Matlab. How to extract support vector from training model in $\nu$-SVR? When I visualize slab tube for a ...
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48 views

Which machine learning method to use for geographic systems prediction?

I am trying to do experiments on geographic systems prediction. We're working on classifying the location where we sell product most. So, we need to analyze the hestorical data and predict the success ...
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30 views

How do interpret statistically NULL SVM Output

I am using LibSVM (3.18) as an implementation of SVM. But every time when I'm predicting the result, it's giving zero. I am following these instructions: I have CSV file (+50K lines), Most of data ...
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3answers
103 views

SVM for unbalanced data

I want to attempt to use Support Vector Machines (SVMs) on my dataset. Before I attempt the problem though, I was warned that SVMs dont perform well on extremely unbalanced data. In my case, I can ...
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74 views

libsvm grid search on Parallel Computing Toolbox Matlab

I am using the following code for grid search on libsvm: ...
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25 views

Liblinear types of solver

There is many variants of type of solver in liblinear but I don't understand their differences.Which one I must choose? Also why data must be scaled? duo to some numerical issues? ...
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1answer
88 views

Rank features by predictive power in trained classifier (LibSVM)

I'm training a SVM classifier on a dataset using LibSVM through Weka, but after I have my trained classifier I'd like to know which features are important to my classifier and which features don't ...
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68 views

libsvm: Cross Validation with imbalanced classes

I am using libsvm for a 2-class classification problem. For my testing I use the C-SVM with RBF kernel. My main problem seems to be that the classes are highly imbalanced. While I have 35000 datasets ...
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25 views

strange behavior for LIBSVM during cross-validation

I am working on a 2-class classification problem and using LIBSVM. I am facing this following problem with cross validation (CV). Any help is highly appreciated. When I perform a 10 fold CV with -v ...
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68 views

Normalized Data vs. Non Normalized Data in SVM Training

Im training an SVM on a dataset containing 17000 events with 30 features. as I see it, this amount of features against the dataset size should suffice by itself for avoiding overfitting. Im training ...
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Leave-one-out cross-validation in LiblineaR

So I've been encountering this weird issue with LiblineaR where I get different results from just running LiblineaR with cross set to the size of my dataset and actually looping through the dataset, ...
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Why even my training data failed during the prediction of libsvm [duplicate]

Currently I'm using libsvm for my one class classification problem. I have 10 samples in my training set, 5 samples in my testing set, both of my training and testing set is scaled by svm_scale, then ...
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69 views

Libsvm includes training data in testing file

Currently I'm using libsvm (Java) for my one class classification problem. I scaled both of my training data and testing data by svm_scale, the problem is that somehow,libsvm includes both training ...
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104 views

Multi class classification always have better result than one class classification?

Currently I'm using svm to classify the test samples to two different classes (True and False). When I use multi class classification, I have both true and false samples in my training set, the ...
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1answer
177 views

LIBSVM Probability estimates in binary classification

I have Training data like following : 1 1:128.319 2:71.4336 3:130.255 4:292.948 5:96.3541 6:71.942 7:136.189 8:71.5032 9:148.21 10:304.011 11:90.3781 12:99.4496 13:164.268 14:138.892 15:220.871 ...
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440 views

One class classification with libsvm. Accuracy results in 0%

A quick recap for what I want to do, I want to determine if a text is written by the same author or not. Thus I use one-class classification. In my training set (18 samples), it looks like this (for ...
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134 views

C parameter does not affect accuracy (LibSVM)

I'm working on LibSVM and I'm using linear kernel. But i have a problem with C parameter, it does not affect accuracy during test set! Is it possible? I send a picture with the distributions of the ...