Phantom Query Engine

Phantom Query Engine

The Phantom_Query class in the provided code is an implementation of a query engine. A query engine is a crucial component of a search engine that takes a user's search query and returns the most relevant documents from the database. The Phantom_Query class uses the TF-IDF (Term Frequency-Inverse Document Frequency) algorithm to rank the documents based on their relevance to the query.

Here's a brief overview of the Phantom_Query class:

• The __init__ method initializes the query engine. It takes as input the name of the input file (filename) and the name of the titles file (titles). It also initializes several other attributes, such as the inverse document frequency (idf), the TF-IDF (tfidf), and a lookup set of all terms in the corpus.

• The query method takes a user's search query and returns the most relevant documents. It first splits the query into terms and filters out the terms that are not in the lookup set. It then calculates the TF-IDF for each term in the query. Next, it calculates the score for each document by summing the product of the TF-IDF of each term in the document and the TF-IDF of the same term in the query. Finally, it ranks the documents based on their scores and returns the top count documents.

• The run method starts the query engine. It continuously prompts the user to enter a query and prints the results of the query.

• The log method is used to log messages.

The Phantom_Query class is used as follows:

1. An instance of the Phantom_Query class is created with the input file name and the titles file name.

2. The run method is called to start the query engine.

The output of the Phantom_Query class is a list of tuples, where each tuple contains the document ID, the score, and the title of a document. The list is sorted in descending order of the scores, so the first tuple corresponds to the most relevant document.