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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How to boost the performance of support vector machine?

I have 4 different data samples: Stage 1: [152 X 27578] Stage 2: [48 X 27578] Stage 3: [48 X 27578] Cancer: [63 X 27578] Each sample are the different stage of cancer in descending order. Here I ...
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23 views

Boosting the prediction results in machine learning

I am having the datasets of 152 samples and 151 features.I implemented libSVM algorithm as a classifier. I am getting a classification accuracy just above 55% Is there any way I can boost my ...
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33 views

linear kernel SVM

The linear kernel is defined as: $K(x1,x2)=\langle x1,x2\rangle$. I can see that all that this kernel does is to calculate the dot product in the original space of the data. Why is this kernel then ...
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42 views

epsilon svr - How to control number of support vector?

I used epsilon SVR in libsvm for predicting time series data, which has approximately 117 rows I used 4 data (t-4, t-3, t-2, t-1) to predict the next data(t). I used gaussian RBF as kernel function. ...
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13 views

Is it acceptable to use class probabilities as weights for a weighted average when the bins are numbers 1 to 5?

I have a Multi Class SVM that can predict what class some observation belongs to. There are 5 classes. They are trained for observation that scored 1 to 5. I want the MC-SVM to predict a class for ...
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37 views

SVM accuracy after log transformation

I am using SVM (RBF kernel, the LibSVM implementation) to deal with a classification problem. When I use a log 10 transformation for may features values instead of using the default scaling method ...
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1answer
34 views

Is validation set important in SVM regression analysis

I am new to machine learning and currently reading a paper about a ANN modelling in which they have divided their dataset into Training , validation and testing set. I have carried out some minor SVM ...
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1answer
18 views

Over sampling imbalance data in SVM

Basically I have a medium size data set (20,000 observations) with only 200 being in group 1, thus an imbalanced data set. My goal is to predict as much group 1 class as possible without sacrificing ...
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29 views

High difference between cv rate and classification accuracy in libsvm

edit: nevermind I solved it I am training an svm on a dataset with 5 classes using libsvm. I have a training set and a test set. I am using the easy.py script. The accuracy is a lot worse than the ...
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1answer
58 views

How probabilities are calculated for SVM model?

I would like to know, how probabilities are calculated in support vector machine. I have used Iris data set and here is my decision values for three "SupportVectorMachine" (please find the PMML below ...
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36 views

How to use svm-scale in LIBSVM?

I tried svm-scale -l 0 -u 1 -s range data.data > data_scaled.data but got error: I run the command in windows DOS command box. And I use python interface. Is my ...
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18 views

How to extract descriptor values correctly from positive images with HOG? OpenCV

I have extracted descriptor values from positive and negative training set. For positive images, I have cropped objects (bicycle) from positive images, and only extracted descriptor values from them, ...
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43 views

Proper scaling of training and test files

I'm trying to classify the web traffic according to the variation of the delay; my goal is to distinguish streaming traffic from downloading traffic. So far, my classes are: ...
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23 views

What is the structure of the testing data file in libsvm? [closed]

According to the README file: The format of training and testing data file is: label index1:value1 index2:value2... My training file would be something like this: ...
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16 views

libsvm to liblinear migration

I've reached the point when svmlib works too long so I decided to switch to liblinear instead. My question is how to properly transfer parameter training from libsvm to liblinear Say, if I have the ...
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1answer
122 views

LibSVM parameter tuning

I am working on LibSVM to classify user comments as negative and positive. I am trying all possible parameter right now however i was not able to find useful information about these parameters Can ...
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79 views

How to input data in libsvm for time series prediction using support vector regression?

I am using libsvm to perform time series prediction using support vector regression. Say my series is [11,22,33,44,55,66,77,88,99] and I decide the value of optimum lag to be 2.So from 11 and 22, I ...
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34 views

Low cross validation accuracy in L1 Logistic Regression

My question is about the use of L1 Logistic Regression for discriminant analysis (feature selection) in extremely large datasets. I am using liblinear https://www.csie.ntu.edu.tw/~cjlin/liblinear/ for ...
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23 views

SVM feature reduction

Suppose task where you need to classify texts using SVM. So before that you need to extract some features from texts. Suppose you pick up many of them and get huge vector. Is there any automatic ...
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22 views

libsvm probability seems inverted

I started using libsvm a few days ago. Previously I used OpenCV implementation of SVM, but I needed probabilities on estimation and a read that with libsvm is possible. I started with a simple example ...
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1answer
44 views

Usage of -b in svm-predict in libsvm

I have to use libsvm for scene-recognition. I have just started reading its usage here in github. I wanted to know what does '-b' exactly does in following usages svm-train -s 0 -b 1 data_file ...
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19 views

How to get best possible model in ONE CLASS SVM

I am using one class SVM on a project. I do not have labeled data. I am not sure what should be the judging criteria to identify the best model. Any Suggestions? Thanks in advance!
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56 views

Bug in libsvm? Adding a single new example crushes everything! [closed]

I have a set of unbalanced examples, i.e. there is much more negatives than positives. Hence, I decided to use an SVM with weighting. However, when I want to figure out the 'best parameters' (cost and ...
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78 views

SVM with non-negative weights

An SVM classifier can be obtained by solving the following, $\arg\min \frac{1}{2}\|W\|_2^2 + C\sum_i \max(0, 1-y_i (W^T\mathbf{x}_i + b))$ where $W$ is the hyperplane (or weights), $b$ is the bias, ...
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241 views

How to get probability from the confidence score in SVM

In liblinear library we can get confidence score (the distance between decision hyperplane) in SVM solver for a binary classification problem, but if i want a probability value for membership in any ...
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45 views

how can I fixed size of grid search in libsvm?

I'm trying to use libsvm to classify a database that contains 1000 labels using svm one vs rest . My goal is to get out the probabilities for each class and to perform accuracy. I know that the first ...
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60 views

How to prove that text is linearly separable?

I sentiment analisys task, for this I used SVM with an rbf kernel and a linear one. The results for the linear kernel were better than the rbf, from this I know that text is linearly separable, but ...
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107 views

Bias terms in SVMs

I'm training multi-class classification models using linear SVMs - by learning binary one-vs-all classifiers for each class. To classify a test instance, I evaluate the following equation for each ...
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1answer
120 views

Only one support vector in a linear svm kernel

I am new to SVM, but I would like to understand certain things. Firstly, when dealing with multiclass classifications, I have a large number of support vectors as proven by R. However, when I run ...
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31 views

Lowering C parameter increases the number of support vectors

I know that the C (cost) parameter controls the trade-off between model complexity and misclassification. A large C should increase the error weight, and therefore the model complexity. Nevertheless, ...
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92 views

SVM always predicts same label

I have 11 labels. I trained an SVM model: ...
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42 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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28 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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368 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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66 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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151 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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64 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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205 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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104 views

What is the time complexity of binary classification of SVM?

One of the earliest solutions 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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57 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
550 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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121 views

Why does Support Vector Regression slow down after several iterations? [on hold]

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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22 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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567 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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57 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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203 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
146 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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204 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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2answers
1k 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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752 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 ...