julien

Julien is a retrieval stack built for performing experiments in Information Retrieval research. The current version of Julien is 0.1, mostly because it's been under development and I haven't had time to really set it up for a release. Right now the documentation is spotty, but I will be shoring it up in the coming weeks. The scaladocs can be found at http://ayr.cs.umass.edu/julien-docs/julien .

Model

Julien is primarily driven by Operators and Processors.

Operators are broken down into Views and Features - views provide channels of information from the index, and features are functions that operate on information provided to eventually produce scores for documents.

Processors encapsulate the logic needed to run a tree of operators over the whole index and return a ranked list of documents. There are other components in making a system, but those two are the most central.

Example: Running a Single Query

Julien was designed to require little outside of specifying the query. In a sense, the philosophy is "if you make the query, it'll run".

import julien.retrieval._

// Implicit so the index is supplied where needed without you having to fill it in
implicit val index = Index.disk("path_to_my_index")

// Our query...
val querytext = "pros and cons of the hyperloop"

// Going to transform it by hand - this can always be wrapped in a function
val root = Combine(
  querytext.split(" ").map { t => 
    Dirichlet(Term(t), IndexLengths())
  }
)

// Let the object create a processor to run it, and return results
val results = QueryProcessor(root)

Adding a new Operator

If you're into creating new retrieval models, then you're going to want your own operators. A good place to start is under the Operator documentation, which describes the root of all the things used to construct queries.