{"id":60342,"library":"flann","title":"FLANN","description":"Fast Library for Approximate Nearest Neighbors, providing efficient high-dimensional nearest neighbor search.","status":"active","version":"2022-10-28","language":"cpp","source_language":null,"source_url":null,"tags":["nearest-neighbors","machine-learning","clustering","high-dimensional"],"install":[{"cmd":"vcpkg install flann","lang":"bash","label":"vcpkg"},{"cmd":"# CMakeLists.txt\nfind_package(flann CONFIG REQUIRED)\ntarget_link_libraries(main PRIVATE flann::flann)","lang":"cmake","label":"CMake"}],"dependencies":[],"imports":[{"symbol":"flann/flann.hpp","correct":"#include <flann/flann.hpp>"}],"quickstart":{"code":"#include <flann/flann.hpp>\n#include <iostream>\n#include <vector>\n\nint main() {\n    std::vector<float> dataset = {1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f};\n    flann::Matrix<float> data(dataset.data(), 3, 2);\n    flann::Index<flann::L2<float>> index(data, flann::KDTreeIndexParams(4));\n    index.buildIndex();\n    std::vector<float> query = {1.5f, 2.5f};\n    flann::Matrix<float> query_mat(query.data(), 1, 2);\n    std::vector<int> indices(1);\n    std::vector<float> distances(1);\n    index.knnSearch(query_mat, indices, distances, 1);\n    std::cout << \"Nearest neighbor index: \" << indices[0] << std::endl;\n    return 0;\n}","lang":"cpp","description":"Build a KD-tree index and perform a nearest neighbor search."},"warnings":[{"fix":"Use flann::flann for the compiled version or flann::flann_cpp for header-only.","message":"FLANN can be header-only or compiled; ensure the correct CMake target is used.","severity":"gotcha","affected_versions":"all"}],"env_vars":null,"search_vec":"'approxim':5 'cluster':22 'dimension':12,25 'effici':9 'fast':2 'flann':1 'high':11,24 'high-dimension':10,23 'learn':21 'librari':3 'machin':20 'machine-learn':19 'nearest':6,13,17 'nearest-neighbor':16 'neighbor':7,14,18 'provid':8 'search':15","created_at":"2026-06-16T19:26:29.555732+00:00","updated_at":"2026-06-16T19:26:29.555732+00:00","problems":[],"ecosystem":"vcpkg","meta_description":null,"install_score":null,"quickstart_score":null,"quickstart_tag":null,"pypi_latest":null,"cli_name":null,"cli_version":null,"type":"library","homepage":null,"github":null,"docs":null,"changelog":null,"pypi":null,"npm":null,"openapi_spec":null,"status_page":null,"smithery":null,"categories":["utility"],"base_url":null,"auth_type":null,"provenance":{"verified_status":null,"verified_at":null,"last_verified":"2026-06-17","next_check":"2026-12-14","install_tag":null}}