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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SVM always predicts same label

I have 11 labels. I trained an SVM model: ...
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10 views

Why are parameters in output of my support vector regression going to zero? [migrated]

I am trying to predict next value in a time series from epsilon-support vector regression using libsvm library in matlab.Following is my code. From an excel file, I am taking first 3500 samples for ...
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18 views

Why is linear svm solver faster than nonlinear solver?

Both linear and non linear SVM solve can be solved using primal or dual problem. Why is linear svm solver faster than nonlinear solver?
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9 views

Why am I getting an empty matrix from svmpredict? [migrated]

I want to make predictions from a simple time series. The observations y=[11,22,33,44,55,66,77,88,99,110] and at time ...
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23 views

set SVM parameter range values for tuning [duplicate]

I am newbie to using svm for classification. I want to tune svm parameters by .TrainAutofunction in EmguCV. But I don't know what are the range(min-max value) of below parameters that I should give to ...
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28 views

how to make or prepare range file in svm-scale in libsvm using matlab

Respected all, I am using LIBSVM, for scaling the input data svm scale function is used. The syntax is 'svm-scale -l -1 -u 1 -s range train > train.scale' or svm-scale -s scaling_parameters ...
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21 views

Class weights in unbalanced SVM classification

The answer to this question says that class weights for unbalanced SVM classification can be picked so that that sums of the weights for each class are equal. Should this be done before ...
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29 views

Bounded and unbounded support vectors for nu-SVMs

How do we find out which of the support vectors for a nu-svm are its bounded or unbounded support vectors? For c-SVMs the test is easy: a support vector with $\alpha_i = C$ denotes a bounded support ...
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17 views

Forward sequential feature selection improving classifier performance?

I was in a bit of a conversation with a co-worker about using forward selection. My training data is on order of ~6,000 w/ dimensionality of 1,200, and testing data on order of ~3,000. Currently, I'm ...
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79 views

Why do one-versus-all multi class SVMs need to be calibrated?

On the wiki page for multi-class support vector machines (https://en.wikipedia.org/wiki/Support_vector_machine#Multiclass_SVM) it states that "it is important that the output functions be calibrated ...
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22 views

What is the time complexity of binary classification of SVM?

One of the earliest solution to the SVM problem is SMO applied to dual form.What is the time complexity of SMO algorithm? What is the best known time complexity to solve SVM algorithm (non linear)?
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45 views

How libsvm performs Cross Validation?

I wanted to know that whether libsvm performs cross validation by preserving the class ratios / label distribution within each fold? My train data is organized. For example if I have 20 training ...
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1answer
217 views

Time series forecasting using Support Vector Machines

I have been trying to use Support Vector Machine method for time series forecasting. I have seen allot of research papers, but nobody shared the code or tool they have used for that. Got some ...
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47 views

Why does Support Vector Regression slow down after several iterations?

TLDR: Why does SVR slow down on my machine after multiple runs in IPython/sklearn? I'm trying to grid-search to optimize some parameters in Support Vector Regression with a problem that has 2 ...
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15 views

Larger Costs and Gammas in SVR

I always thought that larger Costs and Gammas in SVR (epsilon) produce higher complex models (what I know about SVM complexity is based on SVs quantity). Is this right ?
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1answer
203 views

LIBSVM: output of svm-predict is all 0 even though I'm using the test data which was used for training

I'm using libsvm to perform binary classification. I used easy.py for training which is included in libsvm library. After running easy.py, it showed the following in stdout. ...
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23 views

measure the quality of feature vectors in terms of AUC and training time

I have computed 10 features for each example. I did an experiment to figure out which combinations of features can give the best classifier performance. I'm using libSVM for training. I noticed if I ...
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1answer
57 views

The meaning of the output from grid.py in libsvm

I'm a newbie in SVM, and have several questions regarding a tool in libsvm. There's tools/grid.py which tools/README explains as "parameter selection tool for C-SVM classification using 47 the RBF ...
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1answer
85 views

One class SVM to detect outliers

My problem is I want to build a one class SVM classifier to identify the nouns/aspects from test file. The training file has list of nouns. The test has list of words. This is what I've done: ...
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89 views

weka CVParameterSelection for libsvm(one class)

I'm trying to find out optimal parameters for one class libsvm. I read http://weka.wikispaces.com/Optimizing+parameters. I gave the values as G 0.01 0.1 10 ...
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100 views

Weka LibSVM one class classifier always predicts one class

I'm trying to use LibSVM classifier in Weka to build a one class SVM classifier. My training file has list of noun words. My test file has many words. My aim is to use the classifier to predict the ...
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199 views

SVM and SMO main differences

I am unable to clearly see the main differences between SVM & SMO. While I get the fact that SMO provides better algorithm for QP solvers but I see that when I use this in Weka on my MacBook it ...
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1answer
264 views

Grid search error in LIBSVM while optimizing C and g parameters

I am using libsvm for a one-class classification problem. I am trying to select the ideal C and gamma parameters for different kernels(polynomial, linear and rbf) I am using the suggested matlab code ...
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43 views

LibSVM Data Formatting

I cannot get Weka to accept this LibSVM file. I've formatted feature sets using LibSVM before with no problems but for some reason it won't take this file. Here is the specific error: ...
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1answer
100 views

Plotting decision boundary of Logistic Regression (liblinear)

I have liblinear model file for a classifier learned using logistic regression. In the file, they say, the weight vector and intercept term. But when I simply plot it as $$w^Tx + b$$ on the original ...
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1answer
596 views

libsvm on MATLAB with rbf kernel: Compute distance from hyperplane

I have a One-Versus-All classification task with 80 different labels. In order to parallelize the problem to take advantage of multiple nodes on a computer cluster, I first trained 80 binary SVM ...
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346 views

Output of Scikit SVM in multiclass classification always gives same label

I am currently using Scikit learn with the following code: ...
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12 views

Do you know about SVM plait?

I need to know about how I can applied many single SVMs? because I have read about SVM plait that does this kind of classifications that is using many single SVMs to improve the classification process ...
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34 views

My support vectors don't look correct

I am trying to classify a toy dataset using SVM. I only have two features and 20 instances. The decision boundary seems correct, however, the support vectors dont look correct. This is the relevant ...
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68 views

One Class SVM Training in LIBSVM

Could you kindly reply my queries in context of using LIBSVM for One class SVM. Assuming I have samples from one class only, do I need to put a lable for each sample...but a training file without ...
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51 views

LibSVM totalSV for multiclass

I am performing classification of K=9 classes using linear SVM with libSVM (MATLAB warp) I am using 400 samples of data to perform the training and I'm getting: totalSV: 203 I know libSVM uses ...
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41 views

Support Vector Machine with zero bias term

I'm looking for an algorithm to solve SVM with zero bias term. So dual form of such SVM is $max_\alpha \sum_i^n \alpha_i -1/2\sum_i^n \sum_j^ny_iy_jK(x_ix_j)\alpha_i\alpha_j$ subject to: $0 \leq ...
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26 views

SVM tends towards one class

I implemented a 1 vs all multi class SVM using libsvm. When I use the trained SVM to predict it will just assign all the samples to the class that is most abundant. Is there a chance that the data I'm ...
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70 views

The Shogun Machine Learning toolbox for SVM with precomputed kernel and zero bias

Can I use the Shogun Machine Learning toolbox for SVM with precomputed kernel and zero bias. I should be able to input pre-computed kernel and I also should be able to set bias zero.
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71 views

SVM with pre-computed kernel and zero bias

I have an optimization function, where I need to give my own kernel matrix and bias value is zero. The kernel matrix is calculated using the data but there is no specific formula for it. If I have a ...
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1answer
105 views

libsvm: scaling data results in less features?

I've scaled my training and testing data in BASH like so: ...
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14 views

How to account for different ratio of samples during training and detection using a support vector machine (svm)?

Consider the following object recognition case: Detection of objects in an image using a sliding window approach in combination with a svm model. During sliding window search using multiple scale ...
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40 views

How to find a good model for an object recognition case using a support vector machine (svm)?

Consider the following example of an object recognition case: I'm trying to detect objects in an image using histograms of oriented gradients (hog) features. The feature vector resulting from hog is ...
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69 views

LIBSVM for pre-computed kernel and zero bias (b values is zero)

I want to do binary classification and I'm using LIBSVM library for that. I have a precomputed Kernel and my bias value (b) is zero. Can I do this in LIBSVM or do I have to use some other library? ...
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34 views

Usage of libsvm with RBF kernel and no Offset

I'm using libsvm for the binary classification and using a precomputed Kernel. In my particular problem there is no bias term (it's zero). Is there anyway to adjust the bias term in libsvm (and not ...
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131 views

Weka SMOreg and LIBSVM with linear kernel problems

I want to test a dataset in weka using either LIBSVM with an e-SVR or SMOreg for regression. I also choose a linear kernel in both (in SMOreg i use an exponent=1 in a non normalized polykernel). ...
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1answer
80 views

What is the toolkit that implements Cost sensitive Support Vector Machine?

I need implementation of cost sensitive support vector machine. The cost is different for each training example (unlike each class). So problem is to solve $max_\alpha$ $-1/2 \sum_{i,j} ...
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64 views

how to run libsvm with histograms?

My train set is array of histograms, each one is 100x5004, as each histogram represent one action, and it contains 100 points. I have train set of array of size 10x(100x5004), and labels set of size ...
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144 views

bad results with SVM

I have a dataset of 1157 samples. The number of features are 6 and I have only one output. My training error is very poor although I have tried a wide range of cost values and followed the recommended ...
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70 views

usage of libsvm: all the predicted labels are the same

I'm trying to use libsvm to train a classifier on the following dataset: (1) The number of class -1 are the same as the number of class 1 (2) The feature value has been scaled to [-1 1] (3) I've ...
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1answer
117 views

usage of libsvm-matlab version

Based on the readme file in the libsvm package. The svmpredict matlab version function is used in the following way: ...
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266 views

predicting time series with support vector machine using R

I am planning to do time series prediction using support vector Machine. I could not find any materials about time series application of support vector machines using R or Mat-lab. Similar question ...
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194 views

Varying LIBSVM predictions based on test series labels

So I have a pretty well testing SVC train series which puts me into the mid 80 percentile without outrageous C/g values. My current C value is 2.0 and gamma is 0.5. Good numbers across the range ...
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1answer
354 views

How to prepare my data for SVM classifier in matlab

I am new to SVM and Matlab. I would like to have an example how to prepare my data to be as input to the SVM classifer (using libsvm) let us assume that i have a group of words first i have ...
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67 views

Selecting most realistic C and g params after gridsearch

I just ran an extended SVC gridsearch in libsvm on about 9000 multi-dimensional vectors representing a time series. Here are the highest scoring results: ...