Non-Metric Space Library is a cross-platform similarity search library and a toolkit for evaluation of similarity search methods. The goal of the project is to create an effective and comprehensive toolkit for searching in generic non-metric spaces. Why do we care about being comprehensive? Because no single method is likely to be sufficient in all cases. It should also be easy to add new implementations and compare them against existing baselines. These considerations were also factored in the design.
Because exact solutions are hardly efficient in high dimensions and/or non-metric spaces, the main focus is on approximate methods. Some of the implemented approaches are quite efficient. For example, according to the results of a public evaluation, our implementation of the SW-graph outperforms other methods in most cases.
Contributors (including people whose code we incorporated): Bilegsaikhan Naidan, Leonid Boytsov, Lawrence Cayton, Wei Dong, Avrelin Nikita, Alexander Ponomarenko, Yury Malkov, Daniel Lemire.
Leo(nid) Boytsov is a maintainer.
Should you decide to modify the library (and, perhaps, create a pull request), please, use the develoment branch.
A detailed description is given in the manual. The manual also contains instructions for building under Linux and Windows, extending the library, as well as for debugging the code using Eclipse.
Most of this code is released under the Apache License Version 2.0 http://www.apache.org/licenses/.
To acknowledge the use of the library, you could provide a link to this repository and/or cite our SISAP paper [BibTex]. Some other related papers are listed in the end.
The LSHKIT, which is embedded in our library, is distributed under the GNU General Public License, see http://www.gnu.org/licenses/. The k-NN graph construction algorithm NN-Descent due to Dong et al. 2011 (see the links below), which is also embedded in our library, seems to be covered by a free-to-use license, similar to Apache 2.
- A modern compiler that supports C++11: G++ 4.7, Intel compiler 14, Clang 3.4, or Visual Studio 14 (version 12 can also be used, but the project fileds need to be downgraded).
- 64-bit Linux is recommended, but most of our code builds on 64-bit Windows as well.
- Boost (dev version). For Windows, the core library and the standalone sample application do not require Boost.
- Only for Linux: CMake (GNU make is also required)
- Only for Linux: GNU scientific library (dev version)
- Only for Linux: Eigen (dev version)
- An Intel or AMD processor that supports SSE 4.2 is recommended
To compile, go to the directory similarity_search and type:
cmake .
make Note that the directory similarity_search contains an Eclipse project that can be imported into The Eclipse IDE for C/C++ Developers. A more detailed description is given in in the manual.
Examples of using the software can be found in the directory sample_scripts. A good starting point is a script sample_scripts/sample_run.sh. This script uses small data sets stored in this repository. You can also download almost every data set used in our evaluations (see the section Data sets below). The downloaded data needs to be decompressed (you may need 7z, gzip, and bzip2). Then, copy data files to a directory of choice and set the environment variable:
export DATA_DIR=[path to the chosen directory with data files]Note that the benchmarking utility supports caching of ground truth data, so that ground truth data is not recomputed every time this utility is re-run on the same data set.
In this release, we implemented basic Python bindings (for Linux and Python 2.7). Currently, only dense vector spaces are supported. To build the bindings, build the library first. Then, change the directory to python_bindings and type:
sudo make installFor an example of using our library in Python, see the script test_nmslib.py.
Building on Windows is straightforward.
Download Visual Studio 2015 Express for Desktop.
Download and install respective Boost binaries (64-bit version 59). Please, use the default installation directory on disk c: (otherwise, it will be necessary to update project files).
Afterwards, you can simply use the provided Visual Studio solution file. The solution file references several project (*.vcxproj) files: NonMetricSpaceLib.vcxproj is the main project file that is used to build the library itself. The output is stored in the folder similarity_search\x64.
Also note that the core library, the test utilities, as well as examples of the standalone applications (projects sample_standalone_app1 and sample_standalone_app2) can be built without installing Boost.
We use several data sets, which were created either by other folks, or using 3d party software. If you use these data sets, please, consider giving proper credit. The download scripts prints respective BibTex entries. More information can be found in the manual.
Here is the list of scripts to download major data sets:
- Data sets for our NIPS'13 and SISAP'13 papers data/get_data_nips2013.sh.
- Data sets for our VLDB'15 paper data/get_data_vldb2015.sh.
The downloaded data needs to be decompressed (you may need 7z, gzip, and bzip2)
Most important related papers are listed below in the chronological order:
- Bilegsaikhan, N., Boytsov, L. 2015 Permutation Search Methods are Efficient, Yet Faster Search is Possible PVLDB, 8(12):1618–1629, 2015 [BibTex]
- Ponomarenko, A., Averlin, N., Bilegsaikhan, N., Boytsov, L., 2014. Comparative Analysis of Data Structures for Approximate Nearest Neighbor Search. [BibTex]
- Malkov, Y., Ponomarenko, A., Logvinov, A., & Krylov, V., 2014. Approximate nearest neighbor algorithm based on navigable small world graphs. Information Systems, 45, 61-68. [BibTex]
- Boytsov, L., Bilegsaikhan, N., 2013. Engineering Efficient and Effective Non-Metric Space Library. In Proceedings of the 6th International Conference on Similarity Search and Applications (SISAP 2013). [BibTex]
- Boytsov, L., Bilegsaikhan, N., 2013. Learning to Prune in Metric and Non-Metric Spaces. In Advances in Neural Information Processing Systems 2013. [BibTex]
- Dong, Wei, Charikar Moses, and Kai Li. 2011. Efficient k-nearest neighbor graph construction for generic similarity measures. Proceedings of the 20th international conference on World wide web. ACM, 2011. [BibTex]
- Tellez, Eric Sadit, Edgar Chávez, and Gonzalo Navarro. Succinct nearest neighbor search. Information Systems 38.7 (2013): 1019-1030. [BibTex]
- L. Cayton, 2008 Fast nearest neighbor retrieval for bregman divergences. Twenty-Fifth International Conference on Machine Learning (ICML). [BibTex]
- Amato, Giuseppe, Claudio Gennaro, and Pasquale Savino. Mi-file: using inverted files for scalable approximate similarity search. Multimedia tools and applications 71.3 (2014): 1333-1362. [BibTex]
- Gonzalez, Edgar Chavez, Karina Figueroa, and Gonzalo Navarro. Effective proximity retrieval by ordering permutations. Pattern Analysis and Machine Intelligence, IEEE Transactions on 30.9 (2008): 1647-1658. [BibTex]
We are aware of other (numerous) papers on building and querying k-NN graphs (proximity graphs). In our library, we are currently using only two graph construction algorithms (see links below):
- The search-based construction algorithm published by Malkov et al. in 2014 (also presented at SISAP 2012);
- The NN-Descent algorithm due to Dong et al. 2011. This first version came without a search algorithm. Therefore, we use the same search algorithm as Malkov et al. 2014. A newer version of NN-descent can be found by following this link. It is not incorporated, though.