LIBSVM Tools

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This page provides some miscellaneous tools based on LIBSVM. Roughly they include

Things not general enough to be included in LIBSVM
Research codes used in some our past papers
Some data sets in LIBSVM formats

They will be less maintained comparing to the main LIBSVM package. However, comments are still welcome. Please properly cite our work if you find them useful. This supports our future development. -- Chih-Jen Lin

Disclaimer: We do not take any responsibility on damage or other problems caused by using these software and data sets.

LIBLINEAR for One-versus-one Multi-class Classification
Large-scale linear rankSVM
LIBLINEAR for more than 2^32 instances/features (experimental)
How large the training set should be?
Large linear classification when data cannot fit in memory
Weights for data instances
Fast training/testing for degree-2 polynomial mappings of data
Cross Validation with Different Criteria (AUC, F-score, etc.)
Cross Validation using Higher-level Information to Split Data
LIBSVM for dense data
LIBSVM for string data
Multi-label classification
LIBSVM Extensions at Caltech
Feature selection tool
LIBSVM data sets
SVM-toy in 3D
Multi-class classification (and probability output) via error-correcting codes
SVM Multi-class Probability Outputs
An integrated development environment to libsvm
ROC Curve for Binary SVM
Grid Parameter Search for Regression
Radius Margin Bounds for SVM Model Selection
Reduced Support Vector Machines Implementation
LIBSVM for SVDD and finding the smallest sphere containing all data
DAG approach for multiclass classification

LIBLINEAR for One-versus-one Multi-class Classification

LIBLINEAR does not support one-versus-one multi-classification, so we provide an extension here. If k is the number of classes, we generate k(k-1)/2 models, each of which involves only two classes of training data. According to Yuan et al. (2012), one-versus-one is not practical for large-scale linear classification because of the huge space needed to store k(k-1)/2 models. However, this approach may still be viable if model vectors (i.e., weight vectors) are very sparse. Our implementation stores models in a sparse form and can effectively handle some large-scale data.

Please download the zip file. The usage is the same as LIBLINEAR except a new option "-M." Specify "-M 1" to use one-versus-one multi-class classification. For example:

> train -M 1 dataset

Authors: Hsiang-Fu Yu, Chia-Hua Ho and Yu-Chin Juan

Large-scale linear rankSVM

This is an extension of LIBLINEAR for linear rankSVM. Currently it supports L2-regularized L2-loss linear rankSVM.

This code implements methods proposed in the following paper

Ching-Pei Lee and Chih-Jen Lin. Large-scale linear rankSVM, 2013.

Please download the zip file. Details of using this code are in the README.ranksvm file. Except the new solver for rankSVM and the new data format supported in this extension, the usage is the same as LIBLINEAR.

Authors: Ching-Pei Lee

LIBLINEAR for more than 2^32 instances/features (experimental)

This experimental version of liblinear uses 64-bit integer in all possible places, so it in theory can handle up to 2^64 instances/features if memory is enough. Please download the zip file here. Comments are welcome.

Author: Yu-Chin Juan

How large the training set should be?

People tend to use as many data as possible, but the training time can be long. This matlab/octave code (Download) starts with a small subset and shows if larger training subsets increase the cross-validation (CV) accuracy. The code iteratively update the figure of size versus CV accuracy. If you find that the CV accuracy has stabilized, you can stop the code and use only a subset of certain size.

To use, put the code under the compiled liblinear/matlab directory, and open octave or matlab:

> [y,x] = libsvmread('mydata');
> size_acc(y,x);

Currently, only linear classification is supported

Examples:

Author: Po-Wei Wang

Large linear classification when data cannot fit in memory

This is an extension of LIBLINEAR for data which cannot fit in memory. Currently it supports L2-regularized L1- and L2-loss linear SVM, L2-regularized logistic regression, and Cramer and Singer formulation for multi-class classification problems.

This code implements methods proposed in the following papers

Hsiang-Fu Yu, Cho-Jui Hsieh, Kai-Wei Chang, and Chih-Jen Lin. Large linear classification when data cannot fit in memory, ACM Transactions on Knowledge Discovery from Data, 5:23:1--23:23, 2012. Preliminary version at ACM KDD 2010 (Best research paper award).
Kai-Wei Chang and Dan Roth. Selective Block Minimization for Faster Convergence of Limited Memory Large-scale Linear Models, ACM KDD 2011.

Please download the zip file. Details of using this code are in the README.cdblock file. Except new parameters for this extension, the usage is the same as LIBLINEAR.

Authors: Hsiang-Fu Yu and Kai-Wei Chang

Weights for data instances

Users can give a weight to each data instance.
For LIBSVM users, please download the zip file (MATLAB and Python interfaces are included).
For LIBLINEAR users, please download the zip file (MATLAB and Python interfaces are included).

You must store weights in a separated file and specify -W your_weight_file. This setting is different from earlier versions where weights are in the first column of training data.
Training/testing sets are the same as those for standard LIBSVM/LIBLINEAR.
We do not support weights for test data.
All solvers are supported.
Matlab/Python interfaces for both LIBSVM/LIBLIENAR are supported.

We are interested in successful stories of using instance weights. Please keep us informed.

Author: Ming-Wei Chang, Hsuan-Tien Lin, Ming-Hen Tsai, Chia-Hua Ho and Hsiang-Fu Yu.

Fast training/testing for degree-2 polynomial mappings of data

This is an extension of LIBLINEAR for fast training/testing of the degree-2 polynomial mappings of data. Currently it supports L2-regularized L1- and L2-loss linear SVC/SVR.

This code implements one method proposed in the paper
Yin-Wen Chang, Cho-Jui Hsieh, Kai-Wei Chang, Michael Ringgaard, and Chih-Jen Lin. Low-degree Polynomial Mappings of Data for SVM, 2009.

Please download the zip file here. Details of using this code are in the README.poly2 file. Except new parameters for the degree-2 mapping, the usage is the same as LIBLINEAR.

Authors: Yin-Wen Chang, Cho-Jui Hsieh, Kai-Wei Chang, and Yu-Chin Juan

Cross Validation with Different Criteria (AUC, F-score, etc.)

For some unbalanced data sets, accuracy may not be a good criterion for evaluating a model. This tool enables LIBSVM and LIBLINEAR to conduct cross-validation and prediction with respect to different criteria (F-score, AUC, etc.).

Details

Authors: Hsiang-Fu Yu, Chia-Hua Ho, and Cheng-Hao Tsai

Cross Validation using Higher-level Information to Split Data

Assume you have 20,000 images of 200 users:

User 1: 100 images
...
User 200: 100 images

The standard CV may overestimate the performance because of easier predictions: an instance in the validation set may find a close one in the training set. A more suitable setting is to split data by meta-level information (i.e., users here).

Details

LIBSVM for dense data

LIBSVM stores instances as sparse vectors. For some applications, most feature values are non-zeros, so using a dense representation can significantly save the computational time. The zip file here is an implementation for dense data. See README for some comparisons with the standard libsvm.

Author: Ming-Fang Weng

LIBSVM for string data

For some applications, data instances are strings. SVM trains a model using some string kernels. This experimental code (download zip file here) allows string inputs and implements one string kernel. Details are in README.string.

Author: Guo-Xun Yuan

Multi-label classification

This web page contains various tools for multi-label classification.

LIBSVM Extensions at Caltech

You can link to this webpage, which is individually maintained by a PhD student Hsuan-Tien Lin at Caltech. The page contains some programs that he has developed for related research. Most of these programs are extended from/for LIBSVM. Some of the most useful programs include confidence margin/decision value output, infinite ensemble learning with SVM, dense format, and MATLAB implementation for estimating posterior probability.

Feature selection tool

This is a simple python script (download here) to use F-score for selecting features. To run it, please put it in the sub-directory "tools" of LIBSVM.

Usage: ./fselect.py training_file [testing_file]

Output files: .fscore shows importance of features, .select gives the running log, and .pred gives testing results.

More information about this implementation can be found in Y.-W. Chen and C.-J. Lin, Combining SVMs with various feature selection strategies. To appear in the book "Feature extraction, foundations and applications." 2005. This implementation is still preliminary. More comments are very welcome.

Author: Yi-Wei Chen

LIBSVM data sets

We now have a nice web page showing available data sets.

SVM-toy in 3D

A simple applet demonstrating SVM classification and regression in 3D. It extends the java svm-toy in the LIBSVM package.

Go to 3D SVM-toy page

Multi-class classification (and probability output) via error-correcting codes

Note: libsvm does support multi-class classification. The code here implements some extensions for experimental purposes.

This code implements multi-class classification and probability estimates using 4 types of error correcting codes. Details of the 4 types of ECCs and the algorithms can be found in the following paper:

T.-K. Huang, R. C. Weng, and C.-J. Lin. Generalized Bradley-Terry Models and Multi-class Probability Estimates. Journal of Machine Learning Research, 7(2006), 85-115. A (very) short version of this paper appears in NIPS 2004.

The code can be downloaded here. The installation is the same as the standard LIBSVM package, and different types of ECCs are specified as the "-i" option. Type "svm-train" without any arguments to see the usage. Note that both "one-againse-one" and "one-against-the rest" multi-class strategies are part of the implementation.

If you specify -b in training and testing, you get probability estimates and the predicted label is the one with the largest value. If you do not specify -b, this is classification based on decision values. Now we use the "exponential-loss" method in the paper:

Allwein et al.: Reducing multiclass to binary: a unifying approach for margin classifiers. Journal of Machine Learning Research, 1:113--141, 2001,

to predict class label. For one-against-the rest (or called 1vsall), this is the same as the commonly used way
argmax_{i} (decision value of ith class vs the rest).
For one-against-one, it is different from the max-win strategy used in libsvm.

MATLAB code for experiments in our paper is available here

Author: Tzu-Kuo Huang

SVM Multi-class Probability Outputs

This code implements different strategies for multi-class probability estimates from in the following paper

T.-F. Wu, C.-J. Lin, and R. C. Weng. Probability Estimates for Multi-class Classification by Pairwise Coupling. Journal of Machine Learning Research, 2004. A short version appears in NIPS 2003.

After libsvm 2.6, it already includes one of the methods here. You may directly use the standard libsvm unless you are interested in doing comparisons. Please download the tgz file here. The data used in the paper is available here. Please then check README for installation.

Matlab programs for the synthetic data experiment in the paper can be found in this directory. The main program is fig1a.m

Author: Tingfan Wu (svm [at] future.csie.org)

An integrated development environment to libsvm

This is a graphical environment for doing experiments with libsvm. You can create and connect components (like scaler, trainer, predictor, etc) in this environment. The program can be extended easily by writing more "plugins". It was written in python and uses wxPython library. Please download the zip file here. After unzip the package, run the file wxApp1.py. You then have to give the path of libsvm binary files in plugin/svm/svm_interface.py.

Author: Chih-Chung Chang

ROC Curve for Binary SVM

This tool which gives the ROC (Receiver Operating Characteristic) curve and AUC (Area Under Curve) by ranking the decision values. Note that we assume labels are +1 and -1. Multi-class is not supported yet.

You can use either MATLAB or Python.
If using MATLAB, you need to

Download LIBSVM MATLAB interface from LIBSVM page and build it.

Download plotroc.m to the main directory of LIBSVM MALTAB interface.
Type
```
> help plotroc
```

to get usage and examples.

If using Python, you need to

Download LIBSVM (version 2.91 or after) and make the LIBSVM python interface.
Download plotroc.py to the python directory.
Edit the path of gnuplot in plotroc.py in necessary.

The usage is

plotroc.py [-v cv_fold | -T testing_file] [libsvm_options] training_file

Example:
```
> plotroc.py -v 5 -c 10 ../heart_scale
```

If there is no test data, "validated decision values" from cross-validation on the training data are used. Otherwise, we consider decision values of testing data using the model from the training data (without cross-validation).

To use LIBLINEAR, you need the following modifications

MATLAB: Copy plotroc.m to the matlab directory (note that matlab interface is included in LIBLINEAR). Replace svmtrain and svmpredict with train and predict, respectively.

Authors: Tingfan Wu (svm [at] future.csie.org), Chien-Chih Wang (d98922007 [at] ntu.edu.tw), and Hsiang-Fu Yu

Grid Parameter Search for Regression

This file is a slight modification of grid.py in the "tools" directory of libsvm. In addition to parameters C, gamma in classification, it searches for epsilon as well.

Usage: grid.py [-log2c begin,end,step] [-log2g begin,end,step] [-log2p begin,end,step] [-v fold] 
[-svmtrain pathname] [-gnuplot pathname] [-out pathname] [-png pathname]
[additional parameters for svm-train] dataset

Author: Hsuan-Tien Lin (initial modification); Tzu-Kuo Huang (the parameter epsilon); Wei-Cheng Chang.

Radius Margin Bounds for SVM Model Selection

This is the code used in the paper: K.-M. Chung, W.-C. Kao, T. Sun, L.-L. Wang, and C.-J. Lin. Radius Margin Bounds for Support Vector Machines with the RBF Kernel. Please download the tar.bz2 file here. Details of using this code are in the readme.txt file. Part of the optimization subroutines written in Python were based on the module by Travis E. Oliphant.

Author: Wei-Chun Kao with the help from Leland Wang, Kai-Min Chung, and Tony Sun

Reduced Support Vector Machines Implementation

This is the code used in the paper: K.-M. Lin and C.-J. Lin. A study on reduced support vector machines. IEEE Transactions on Neural Networks, 2003.

Please download the .tgz file here. After making the binary files, type svm-train to see the usage. It includes different methods to implement RSVM.

To speed up the code, you may want to link the code to optimized BLAS/LAPACK or ATLAS.

Author: Kuan-Min Lin

LIBSVM for SVDD and finding the smallest sphere containing all data

SVDD is another type of one-class SVM. We implement the formulation in Tax and Duin, Support Vector Data Description, Machine Learning, vol. 54, 2004, 45-66. Please download this zip file, put sources into libsvm-3.1 (available here), and make the code. The options are

-s 5 SVDD
-s 6 gives the square of the radius for L1-SVM
-s 7 gives the square of the radius for L2-SVM

MATLAB interface is supported; see the matlab sub-directory.

Authors: Leland Wang, Holger Froehlich (University of Tuebingen), Konrad Rieck (Fraunhofer institute), Chen-Tse Tsai, Tse-Ju Lin

DAG approach for multiclass classification

In svm.cpp, please replace the following lines in the subtoutine svm_predict()

	double pred_result = svm_predict_values(model, x, dec_values);
	free(dec_values);
	return pred_result;

with this segment of code.

This follows from the code used in the paper: C.-W. Hsu and C.-J. Lin. A comparison of methods for multi-class support vector machines , IEEE Transactions on Neural Networks, 13(2002), 415-425.

Author: Chih-Wei Hsu

Please contact Chih-Jen Lin for any question.