rerank

rerank

rerank is a lightweight TypeScript library designed for combining multiple ranked lists into a single, improved rank list using various rank aggregation techniques. As of the current release, rerank supports the Reciprocal Rank Fusion (RRF) method, renowned for its effectiveness in information retrieval and ensemble learning contexts.

Features

• Reciprocal Rank Fusion (RRF): Combine multiple rank lists by assigning scores based on reciprocal ranks, effectively prioritizing higher-ranked items across all lists.

Installation

Install rerank using npm:

npm install rerank

Example Usage

import { reciprocalRankFusion } from "rerank";

interface ImageSearchResult {
  url: string;
  width: string;
  height: string;
  score: number
}

// assume you are searching 3 different queries 
const rankedLists:ImageSearchResult[][] = await Promise.all([
    searchIndex("imageEmbeddingIndex", "person riding skateboard"),
    searchIndex("imageEmbeddingIndex", "person skating on the sidewalk"),
    searchIndex("imageIndex", "skateboard trick")
    ]);

// perform reciprocal rank fusion on all of the results and specify key id, in this case "url"
// this will return a map of all urls now ranked with rrf score
const rankedURLs = reciprocalRankFusion(rankedLists, "url");

// build map of results keyed by url
const resultsMap = new Map<string, ImageSearchResult>();
rankedLists.flat().forEach((result) => {
  resultsMap.set(result.url, result);
});

// get single sorted results list from rrf
const sortedResults = Array.from(rankedUrls.keys()).map((url) => {
  return resultsMap.get(url);
});