diff --git a/README.markdown b/README.markdown
new file mode 100644
index 0000000..7f06335
--- /dev/null
+++ b/README.markdown
@@ -0,0 +1,19 @@
+# context
+
+Copyright (C) 2012 Romain Deveaud <romain.deveaud@gmail.com>
+
+License
+=======
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
diff --git a/context.rb b/context.rb
new file mode 100644
index 0000000..1152268
--- /dev/null
+++ b/context.rb
@@ -0,0 +1,63 @@
+#!/usr/bin/env ruby
+
+require 'mirimiri'
+require 'sanitize'
+require 'lda-ruby'
+
+module Context
+  IndexPaths = {
+    :web_en        => '/mnt/disk2/ClueWeb09_English_1_sDocs',
+    :web_fr        => '/mnt/disk2/ClueWeb09_French_1_sDocs',
+    :web_nospam    => '/mnt/disk1/ClueWeb09_English_1noSpam',
+    :gigaword      => '/local/data/GigaWord/index',
+    :nyt           => '/local/data/NYT_index',
+    :wiki_en       => '/local/data/WikiEn_index',
+    :wiki_fr       => '/local/data/WikiFr_index'
+  }
+
+  def Context.term_context index_path,query,size,num_page,args={}
+    args[:func]   ||= :entropy
+    args[:window] ||= 1
+
+    docs     = self.feedback_docs  index_path,query,num_page
+
+    resource = Mirimiri::Document.new docs.join(' ')
+    terms    = self.extract_ngrams resource,args[:func].to_sym,args[:window]
+
+    context = "#weight ( #{terms.compact.sort{ |a,b| b[0] <=> a[0]}[0,size].collect { |e| "#{e[0]} #1(#{e[1]})" }.join " "} ) " unless terms.empty?
+
+    context
+  end
+
+  def Context.topic_context index_path,query,size,num_page,args={}
+    corpus = Lda::Corpus.new
+
+    docs   = self.feedback_docs index_path,query,num_page
+    docs.each do |d| 
+      doc = Lda::TextDocument.new corpus,d
+      corpus.add_document doc
+    end
+
+    lda = Lda::Lda.new corpus
+    lda.num_topics = num_page/10
+    lda.em 'random'
+    puts lda.top_words(size)
+  end
+
+  private
+  def Context.feedback_docs index_path,query,num_page
+    query = Indri::IndriQuery.new({:query => query, :count => num_page},"-printDocuments=true -trecFormat=true")
+    index = Indri::IndriIndex.new index_path
+    idocs = Indri::IndriPrintedDocuments.new(index.runquery(query).force_encoding("ISO-8859-1").encode("UTF-8"))
+
+    docs = idocs.extract_docs.collect { |idoc| Sanitize.clean idoc,:remove_contents => ['script']  }
+    docs
+  end
+
+  def Context.extract_ngrams resource,func,n
+    raw_terms = 1.upto(n).collect      { |i| resource.ngrams(i) }.flatten
+    terms     = raw_terms.uniq.collect { |w| [resource.send(func.to_sym,w), w.unaccent] unless w.is_stopword? || w.split.all? { |e| e.length <= 1 } || w.split.all? { |e| e !~ /[a-zA-Z]/ } || w.include?(".") }
+    terms
+  end
+
+end