Mahout 搭配 JRuby 建立環境與簡單測試

Oct 14, 2012

建立環境

下載&安裝 Mahout
- https://cwiki.apache.org/confluence/display/MAHOUT/BuildingMahout
下載&安裝 Hadoop
- http://www.apache.org/dyn/closer.cgi/hadoop/common/
- 單機安裝步驟 http://hadoop.apache.org/common/docs/stable/single_node_setup.html
設定 ClASSPATH

 export CLASSPATH=.:~/Project/Mahout/mahout-distribution-0.7/mahout-core-0.7.jar:~/Project/Mahout/mahout-distribution-0.7/mahout-math-0.7.jar:~/Project/Mahout/mahout-distribution-0.7/lib/'*'

簡單測試

可以從 https://github.com/tdunning/MiA 下載 Mahout in Action 的範例程式, 這邊選擇第2章的 RecommenderIntro.java 來將他改寫為 JRuby 的版本, 改寫的結果如下

require 'java'

module Mahout
  include_package "org.apache.mahout.cf.taste.impl.model.file";
  include_package "org.apache.mahout.cf.taste.impl.neighborhood";
  include_package "org.apache.mahout.cf.taste.impl.recommender";
  include_package "org.apache.mahout.cf.taste.impl.similarity";
  include_package "org.apache.mahout.cf.taste.model";
  include_package "org.apache.mahout.cf.taste.neighborhood";
  include_package "org.apache.mahout.cf.taste.recommender";
  include_package "org.apache.mahout.cf.taste.similarity";

end

model = Mahout::FileDataModel.new( java.io.File.new("intro.csv"));

similarity = Mahout::PearsonCorrelationSimilarity.new(model);
neighborhood = Mahout::NearestNUserNeighborhood.new(2, similarity, model);

recommender = Mahout::GenericUserBasedRecommender.new( model, neighborhood, similarity);

recommendation =recommender.recommend(1, 1);

puts recommendation