This project contains a JNA (Java Native Access) implementation built on top of the native Hnswlib (Hierarchical Navigable Small World Graph) which offers a fast approximate nearest neighbor search. It includes some modifications and simplifications in order to provide Hnswlib features with native like performance to applications written in Java. Differently from the original Python implementation, the multi-thread support is not included in the bindings itself but it can be easily implemented on the Java side. Hnswlib-jna works in collaboration with a shared library which contains the native code. For more information, please check the sections below.

The jar file includes some pre-generated libraries for Windows, Debian Linux and MacOS (x86-64) which should allow an easy integration and abstract all complexity related to compilation. In the case of operating system issues, a runtime exception will be thrown and the manual compilation will be advised.

On Windows, the Build Tools for Visual Studio 2019 (C++ build tools) is required.

Add the following dependency in your pom.xml:

<dependency>
    <groupId>com.stepstone.search.hnswlib.jna</groupId>
    <artifactId>hnswlib-jna</artifactId>
    <version>1.3.1-SNAPSHOT</version>
</dependency>

For more information and implementation details, please check hnswlib-jna-example.

This section includes more information about how to compile the shared libraries on Windows, Linux and Mac for different architectures (e.g., x86-64, aarch64). If you were able to run the example project on your PC, this section can be ignored.

To generate the shared library required by this project, binding.cpp needs to be compiled using a C compiler (e.g., clang or gcc) with C++11 support, at least. The library can be generated with clang via:

clang++ -O3 -shared bindings.cpp -I hnswlib -o <project_folder>/lib/libhnswlib-jna-x86-64.dylib

Note: The shared library's name must be: libhnswlib-jna-ARCH.EXT where ARCH is the canonical architecture name (e.g., x86-64 for amd64, or aarch64 for ARM64) and EXT is dylib for MacOS, for windows use dll, and linux so.

1. Download and install LLVM;
2. Download and install Build Tools for Visual Studio 2019 (or higher);
3. Compile the bindings using clang:

clang++ -O3 -shared bindings.cpp -I hnswlib -o <project_folder>/lib/libhnswlib-jna-x86-64.dll

This procedure will generate the 3 necessary files: libhnswlib-jna-x86-64.dll, libhnswlib-jna-x86-64.exp and libhnswlib-jna-x86-64.lib.

1. Download and install LLVM;
2. Make sure that LLVM's bin folder is in your PATH;
3. Download MinGW-w64 with Headers for Clang;
4. Unpack the archive and include MinGW64's bin folder into your PATH as well;
5. Compile the bindings using clang:

clang++ -O3 -target x86_64-pc-windows-gnu -shared bindings.cpp -I hnswlib -o <project_folder>lib/libhnswlib-jna-x86-64.dll -lpthread

This procedure will generate libhnswlib-jna-x86-64.dll.

1. Download and install clang (older versions might trigger compilation issues, so it is better use a recent version);
2. Compile the bindings using clang:

clang++ -O3 -fPIC -shared -std=c++11 bindings.cpp -I hnswlib -o <project_folder>/lib/libhnswlib-jna-x86-64.so

This procedure will generate libhnswlib-jna-x86-64.so.

Once the shared library is available, it is necessary to tell the JVM and JNA where it is located. This can be done by setting the property jna.library.path via JVM parameters or system properties.

-Djna.library.path=<project_folder>/lib

System.setProperty("jna.library.path", "<project_folder>/lib");

For more information and implementation details, please check hnswlib-jna-example.

Copyright 2020 StepStone Services

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.