• Measuring Search Relevance using NDCG

    Vijay Mhaskar

    Normalized Discounted Cumulative Gain (NDCG) is popular method for measuring the quality of a set of search results. It asserts the following: Very relevant results are more useful than somewhat relevant results which are more

  • Query Rescoring in Solr

    Vijay Mhaskar

    Introduction Sometimes relevance requirements are very complex and creates performance issues during execution. There is a very nice feature Introduced in Solr 4.9 called “Query Reranking/Rescoring” (SOLR-6088) which allows us to run our query with a less

  • Test Driven Development by example

    Vijay Mhaskar

    Test-driven development (TDD) is a software development process that relies on the repetition of a very short development cycle. First the developer writes an (initially failing) automated test case that defines a desired improvement or new

  • Understanding PhraseQuery and Slop in Solr

    Vijay Mhaskar

    PhraseQuery in Lucene matches documents containing a particular sequence of terms. PhraseQuery uses positional information of the term that is stored in an index. The number of other words permitted between words in query phrase