simple-search-engine

This is a command-line-based simple text search engine using vector space model with positional indexes which includes a naive pseudo relevance feedback feature build on top of Rocchio algorithm. Cosine similarity is used as a relevance measurement.

Requirements

• At least Java 8 (the codes heavily abuse the Java 8 Streams feature)
• A terminal (this is a command-line-based application!)

How to use

• Compile the codes by executing javac *.java
• Stopwords and sample collections are included in this repository, to begin indexing document collections run this command:

java MySearchEngine index /path/to/collections /path/to/index-dir /path/to/stopwords.txt

• The previous command will create an index file (index.txt) located in the /path/to/index-dir/index.txt
• To perform searches on the newly created index execute the following command:

java MySearchEngine search /path/to/index-dir [num_docs_to_retrive] [keyword_list_separated_by_space]

• After executing the command, the system will return list of documents ordered based on the similarity score, the maximum documents returned would be the number specified on [num_docs_to_retrive] parameter
• To try the naive pseudo relevance feedback feature, add addtional flag -rf to the previous command:

java MySearchEngine search /path/to/index-dir -rf [num_docs_to_retrive] [keyword_list_separated_by_space]