SimhashDB

SimhashDB is a fast and scalable framework for searching nearest neighbor documents using Simhash algorithm.

The framework is made of the following submodule

• Core : SimHash algorithm
• KNN : In memory database for nearest neighbor search
• Text transform : Tools to transform text into binary footprint
• Text transform Terrier: Tools to transform text into binary footprint using the Terrier IR engine
• Examples : some code samples
• KNN Benchmark : jmh benchmark to assess KNN performance

Basics

The core module transforms any Map of key values where keys are String and value are Double into a binary footprint (BitSet). The KNN module offers the storage layer where binary footprints are inserted and requested. The storage is in-memory only for now. Nearest neighbor documents can be searched with either a top-k or Hamming ball query.

Performance

Sample use

Clone the git repository and run mvn install Alternatively see the Maven Section to use the github hosted repository

Maven

First you need to setup the server in your pom.xml :

<repositories>
  <repository>
    <id>simhashdb-mvn-repo</id>
    <url>https://raw.github.com/jsubercaze/simhashdb/mvn-repo/</url>
    <snapshots>
        <enabled>true</enabled>
        <updatePolicy>always</updatePolicy>
    </snapshots>
  </repository>
</repositories>

Then use the following dependency :

<dependency>
 <groupId>fr.ujm.tse.lt2c.satin</groupId>
  <artifactId>simhashdb</artifactId>
  <version>0.0.2-SNAPSHOT</version>
</dependency>

Publication

If you used Simhashdb in a publication please contact me so that I add it to the list

• Julien Subercaze, Christophe Gravier, Frederique Laforest. Real-Time, Scalable, Content-based Twitter users recommendation. Web Intelligence and Agent Systems : An International Journal (WIAS), 2015 PDF