NSG

title: NSG slug: nsg url: https://github.com/ZJULearning/nsg brand: zjulearning category: sdks-libraries featured: false images:

• https://opengraph.githubassets.com/1/ZJULearning/nsg Tags:
• ann
• graph-index
• similarity-search

Overview

NSG (Navigating Spread-out Graph) is a graph-based approximate nearest neighbor search (ANNS) algorithm designed for large-scale, high-dimensional vector similarity search. It builds a sparse navigable graph over dense real-valued vectors to enable efficient, metric-free approximate nearest neighbor queries, and is provided as a reference implementation that can be integrated into custom vector retrieval systems.

Features

• Graph-based ANN index
  Builds a sparse navigable graph structure over vector datasets for approximate nearest neighbor search.

• Approximate Nearest Neighbor Search (ANNS)
  Implements ANNS for dense real-valued vectors, targeting high efficiency and scalability.

• Metric-free design
  Designed for metric-free, large-scale ANN search on dense vectors, not tied to a specific distance metric.

• Reference implementation of NSG algorithm
  Implements the algorithm from the PVLDB paper “Fast Approximate Nearest Neighbor Search With The Navigating Spread-out Graphs”.

• Large-scale / billion-scale readiness
  Used in production (e.g., Taobao search engine) for billion-scale ANN search in e-commerce scenarios, indicating suitability for very large datasets.

• Library / SDK structure

  • C++ source code under src and include/efanna2e
  • Python bindings under pynsg
  • CMake-based build configuration (CMakeLists.txt)
  • Dockerfile for containerized builds and experiments
  • Test suite under tests for validation

• Research-oriented codebase
  Organized to support experimentation and benchmarking of NSG against other ANN algorithms, including figures and performance evaluation materials.

Technology

• Language: Primarily C++ (with Python bindings via pynsg).
• Build system: CMake; Docker support via provided Dockerfile.

Licensing

• License file included (LICENSE) in the repository; users should consult it directly for exact terms.

Pricing

• NSG is an open-source research implementation hosted on GitHub. No pricing or paid plans are specified in the available content.