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This is the Ruby LIBLINEAR SWIG (Simplified Wrapper and Interface Generator) interface. LIBLINEAR is a high performance machine learning library for large scale text mining(

A slightly modified version of LIBLINEAR 1.8 is included which allows turning on/off the default debuging/logging messages. You don't need your own copy of SWIG to use this library - all needed files are generated using SWIG already.

LIBLINEAR is in use at - A Twitter / Tweet sentiment analysis application


Currently the gem is available on linux and OS X, and you will need g++ installed to compile the native code.

sudo gem sources -a   (you only have to do this once)
sudo gem install tomz-liblinear-ruby-swig


Try the following multiclass problem in irb:

irb(main):001:0> require 'rubygems'
irb(main):002:0> require 'linear'
irb(main):003:0> pa =
irb(main):004:0> pa.solver_type = MCSVM_CS 
irb(main):005:0> pa.eps = 0.1
irb(main):006:0> bias = 1
irb(main):007:0> labels = [1, 2, 1, 2, 3]
irb(main):008:0> samples = [
irb(main):009:1*            {1=>0,2=>0.1,3=>0.2,4=>0,5=>0},
irb(main):010:1*            {1=>0,2=>0.1,3=>0.3,4=>-1.2,5=>0},
irb(main):011:1*            {1=>0.4,2=>0,3=>0,4=>0,5=>0},
irb(main):012:1*            {1=>0,2=>0.1,3=>0,4=>1.4,5=>0.5},
irb(main):013:1*            {1=>-0.1,2=>-0.2,3=>0.1,4=>1.1,5=>0.1}
irb(main):014:1>           ]
irb(main):016:0> sp =,samples,bias)
irb(main):017:0> m =, pa)
irb(main):018:0>  pred = m.predict({1=>1,2=>0.1,3=>0.2,4=>0,5=>0})
=> 1
irb(main):019:0>  pred = m.predict({1=>0,2=>0.1,3=>0.2,4=>0,5=>0})
=> 2
irb(main):020:0>  pred = m.predict({1=>0,2=>0.1,3=>0.2,4=>0,5=>0})
=> 2
irb(main):025:0>  pred = m.predict({1=>0.4,2=>0,3=>0,4=>0,5=>0})
=> 1
irb(main):021:0>  pred = m.predict({1=>-0.1,2=>-0.2,3=>0.1,4=>1.1,5=>0.1})
=> 3

For more examples see test*.rb in the liblinear-ruby-swig/liblinear-1.8/ruby directory


Tom Zeng