Pegasos algorithm for one-class SVM (one_class_svm_tool)


"Pegasos algorithm for one-class SVM" is a training algorithm for one-class support vector machinie (one-class SVM). This algorithm is much faster than the standard one-class SVM without loss of performance in the case of linear kernel.


Changki Lee. Pegasos Algorithm for One-Class Support Vector Machine. IEICE Transactions on Information and Systems, Vol.E96-D, No.5, May 2013, pp.1223-1226.
Changki Lee. 1-Slack One-Class SVM for Fast Learning. Journal of KIISE, ISSN:1229-7712, VOL.19, NO.5, May 2013, pp.253-257.

Data format

This is the training/testing file format of one_class_svm_tool.
(binary feature)
[label] [string_feature1] [string_feature2] ...
[label] [string_feature1] [string_feature2] ...
label is the class of your one-class SVM (1 or -1).
string_feature_n is a feature string that have 1 as a feature value.
(general feature)
[label] [string_feature1:value] [string_feature2:value] ...
[label] [string_feature1:value] [string_feature2:value] ...


Please read the COPYRIGHT notice before using one_class_svm_tool.


one_class_svm_tool 2013.1

A command line utility to train/test one-class SVM.

Usage: one_class_svm_tool [OPTIONS]... [FILES]...

  -h, --help             Print help and exit
  -V, --version          Print version and exit

Training options:
  -c, --cost=FLOAT       set Cost of one class SVM (cost=1/lambda for SGD)
  -m, --model=STRING     set model file name
      --skip_eval        skip test set evaluation in the middle of training
  -r, --random=INT       use random_shuffle in train_data (disabled if use 0)
      --train_num=INT    set number of sentence in train_data for training (for
                           experiments) (disabled if use 0)  (default=`0')
  -i, --iter=INT         iterations for training algorithm (sgd)
  -t, --tol=FLOAT        set Tolerance  (default=`1e-03')
      --period=INT       save model periodically (sgd)  (default=`0')
  -v, --verbose          verbose mode  (default=off)

Predict options:
  -o, --output=STRING    prediction output filename

one class SVM options:
  -e, --epsilon=FLOAT    set epsilon  (default=`0.001')
      --buf=INT          number of new constraints to accumulated before
                           recomputing the QP (sgd)  (default=`10')
      --rm_inactive=INT  inactive constraints are removed (iteration)
                           (one_slack_smo)  (default=`50')

Kernel options:
      --kernel=INT       kernel type (0=Linear 1=POLY 2=RBF 3=SIGMOID in SVMs)
      --gamma=FLOAT      gamma in RBF kernel (in SVMs)  (default=`1e-5')
      --coef=FLOAT       coef in POLY/SIGMOID kernel (in SVMs)  (default=`1')
      --degree=INT       degree in POLY kernel (in SVMs)  (default=`3')

 Group: MODE
  -p, --predict          prediction mode, default is training mode
      --show             show-feature mode
      --remove_zero      remove zero-value features (with --tol threshold)

 Group: Parameter Estimate Method
      --one_slack        use 1-slack one class SVM without Gram matrix (linear
                           kernel only)
      --one_slack2       use 1-slack one class SVM using Gram matrix (linear
                           kernel only)
      --sgd              use SGD (Pegasos) in primal optimization (random
                           shuffled train_data)
      --sgd2             use SGD (Pegasos) in primal optimization (pick random

Example of options

$ one_class_svm_tool --sgd -c 1000 -m model.txt train.feature.txt test.feature.txt
$ one_class_svm_tool -p -m model.txt -o output.txt test.feature.txt