INSTALL file for Faiss (Fair AI Similarity Search)
Install via Conda
The easiest way to install FAISS is from anaconda. We regularly push stable releases to conda channel. FAISS conda package is built with conda gcc, depends on libgcc, mkl and numpy package shipped in conda in runtime.
Currently we support faiss-cpu on both Linux and OSX platforms. We also provide faiss-gpu compiled with CUDA8.0/CUDA9.0/CUDA9.1 on Linux systems.
You can easily install it by
# CPU version only conda install faiss-cpu -c pytorch # Make sure you have CUDA installed before installing faiss-gpu, otherwise it falls back to CPU version conda install faiss-gpu -c pytorch # [DEFAULT]For CUDA8.0 conda install faiss-gpu cuda90 -c pytorch # For CUDA9.0 conda install faiss-gpu cuda91 -c pytorch # For CUDA9.1 # cuda90/cuda91 shown above is a feature, it doesn't install CUDA for you.
Compile from source
The Faiss compilation works in 3 steps, from easiest to most involved:
compile the C++ core and examples
compile the Python interface
compile GPU part
Steps 2 and 3 depend on 1, but they are otherwise independent.
Alternatively, all 3 steps above can be run by building a Docker image (see section "Docker instructions" below).
Alternatively, steps 1 and 3 can be built via the cmake scripts (see below).
It is also possible to build a pure C interface. This optional process is described separately (please see the C interface installation file)
General compilation instructions
Faiss has been tested only on x86_64 machines on Linux and Mac OS.
Faiss is compiled via a Makefile. The system-dependent configuration of the Makefile is in an include file, makefile.inc. The variables in makefile.inc must be set by hand.
Faiss requires a C++ compiler that understands:
- the Intel intrinsics for SSE instructions
- the GCC intrinsic for the popcount instruction
- basic OpenMP
There are a few models for makefile.inc in the example_makefiles/ subdirectory. Copy the relevant one for your system and adjust to your needs. There are also indications for specific configurations in the troubleshooting section of the wiki.
Faiss comes as a .a archive, that can be linked with executables or dynamic libraries (useful for the Python wrapper).
Step 1: Compiling the C++ Faiss
./configure && make && make install
The CPU version of Faiss is written in C++11.
The only variables that need to be configured for the C++ Faiss are the BLAS/Lapack flags (a linear aglebra software package). It needs a flag telling whether BLAS/Lapack uses 32 or 64 bit integers and the linking flags. Faiss uses the Fortran 77 interface of BLAS/Lapack and thus does not need an include path.
There are several BLAS implementations, depending on the OS and machine. To have reasonable performance, the BLAS library should be multithreaded. See the example makefile.inc's for hints and examples on how to set the flags, or simply run the configure script:
To check that the link flags are correct, and verify whether the implementation uses 32 or 64 bit integers, you can
Once the proper BLAS flags are set, the library should compile smoothly by running
Then, in order to install the library and the headers, run
A basic usage example is in
it makes a small index, stores it and performs some searches. A normal runtime is around 20s. With a fast machine and Intel MKL's BLAS it runs in 2.5s.
To run the whole test suite:
A real-life benchmark
A bit longer example runs and evaluates Faiss on the SIFT1M dataset. To run it, please download the ANN_SIFT1M dataset from
and unzip it to the subdirectory
sift1M at the root of the source
directory for this repository.
Then compile and run the following (after ensuring you have installed faiss):
make demos ./demos/demo_sift1M
This is a demonstration of the high-level auto-tuning API. You can try setting a different index_key to find the indexing structure that gives the best performance.
Step 2: Compiling the Python interface
The Python interface is compiled with
If you want to compile it for another python version than the default Python 2.7, in particular Python 3, the PYTHONCFLAGS must be adjusted in makefile.inc, see the examples.
How it works
The Python interface is provided via SWIG (Simple Wrapper and Interface Generator) and an additional level of manual wrappers (in python/faiss.py).
SWIG generates two wrapper files: a Python file (
python/swigfaiss.py) and a
C++ file that must be compiled to a dynamic library (
files are included in the repository, so running swig is only required when
the C++ headers of Faiss are changed.
The C++ compilation to the dynamic library requires to set:
SHAREDFLAGS: system-specific flags to generate a dynamic library
PYTHONCFLAGS: include flags for Python
See the example makefile.inc's on how to set the flags.
Testing the Python wrapper
Often, a successful compile does not mean that the library works, because missing symbols are detected only at runtime. You should be able to load the Faiss dynamic library:
python -c "import faiss"
In case of failure, it reports the first missing symbol. To see all missing symbols (on Linux), use
ldd -r _swigfaiss.so
Sometimes, problems (eg with BLAS libraries) appear only when actually calling a BLAS function. A simple way to check this
python -c "import faiss, numpy faiss.Kmeans(10, 20).train(numpy.random.rand(1000, 10).astype('float32'))
The following script extends the demo_sift1M test to several types of indexes. This must be run from the root of the source directory for this repository:
mkdir tmp # graphs of the output will be written here PYTHONPATH=. python demos/demo_auto_tune.py
It will cycle through a few types of indexes and find optimal operating points. You can play around with the types of indexes.
Step 3: Compiling the GPU implementation
There is a GPU-specific Makefile in the
gpu/ directory. It depends on
the same ../makefile.inc for system-specific variables. You need
libfaiss.a from Step 1 for this to work.
The GPU version is a superset of the CPU version. In addition it requires the cuda compiler and related libraries (Cublas)
See the example makefile on how to set the flags.
The nvcc-specific flags to pass to the compiler, based on your desired compute capability. Only compute capability 3.5+ is supported. For example, we enable by default:
-gencode arch=compute_35,code="compute_35" -gencode arch=compute_52,code="compute_52" -gencode arch=compute_60,code="compute_60"
However, look at https://developer.nvidia.com/cuda-gpus to determine what compute capability you need to use, and replace our gencode specifications with the one(s) you need.
Most other flags are related to the C++11 compiler used by nvcc to complile the actual C++ code. They are normally just transmitted by nvcc, except some of them that are not recognized and that should be escaped by prefixing them with -Xcompiler. Also link flags that are prefixed with -Wl, should be passed with -Xlinker.
Then compile with
cd gpu; make
You may want to add
-j 10 to use 10 threads during compile.
Testing the GPU implementation
Compile the example with
cd gpu; make tests/demo_ivfpq_indexing_gpu
This produce the GPU code equivalent to the CPU demo_ivfpq_indexing. It also shows how to translate indexed from/to the GPU.
Compiling the Python interface with GPU support
Given step 2, adding support of the GPU from Python is quite straightforward. Run
cd python; make _swigfaiss_gpu.so
The import is the same for the GPU version and the CPU-only version.
python -c "import faiss"
Faiss tries to load the GPU version first, and in case of failure, loads the CPU-only version. To investigate more closely the cause of a failure, you can run:
python -c "import _swigfaiss_gpu"
Python example with GPU support
The auto-tuning example above also runs on the GPU. Edit
demos/demo_auto_tune.py at line 100 with the values
keys_to_test = keys_gpu use_gpu = True
and you can run
export PYTHONPATH=. python demos/demo_auto_tune.py
to test the GPU code.
For using GPU capabilities of Faiss, you'll need to run "nvidia-docker" rather than "docker". Make sure that docker (https://docs.docker.com/engine/installation/) and nvidia-docker (https://github.com/NVIDIA/nvidia-docker) are installed on your system
To build the "faiss" image, run
nvidia-docker build -t faiss .
or if you don't want/need to clone the sources, just run
nvidia-docker build -t faiss github.com/facebookresearch/faiss
If you want to run the tests during the docker build, uncomment the last 3 "RUN" steps in the Dockerfile. But you might want to run the tests by yourself, so just run
nvidia-docker run -ti --name faiss faiss bash
and run what you want. If you need a dataset (like sift1M), download it inside the created container, or better, mount a directory from the host
nvidia-docker run -ti --name faiss -v /my/host/data/folder/ann_dataset/sift/:/opt/faiss/sift1M faiss bash
How to use Faiss in your own projects
The makefile generates a static and a dynamic library
libfaiss.a libfaiss.so (or libfaiss.dylib)
the executable should be linked to one of these. If you use the static version (.a), add the LDFLAGS used in the Makefile.
For binary-only distributions, the include files should be under
faiss/ directory, so that they can be included as
#include <faiss/IndexIVFPQ.h> #include <faiss/gpu/GpuIndexFlat.h>
To import Faiss in your own Python project, you need the files
faiss.py swigfaiss.py / swigfaiss_gpu.py _swigfaiss.so / _swigfaiss_gpu.so
to be visible in the PYTHONPATH or in the current directory. Then Faiss can be used in python with
CMake build instructions:
Alternatively, Faiss can be built via the experimental cmake scripts. The installation process is similar to using Makefiles. After installing the necessary dependencies (OpenBLAS, OpenMP, and CUDA, if BUILD_WITH_GPU is enabled), the build process can be done by the following commands:
mkdir build cd build cmake .. make # use -j to enable parallel build
Notes for build on Mac: The native compiler on Mac does not support OpenMP.
So to make it work on Mac, you have to install a new compiler using either
Macports or Homebrew. For example, after installing the compiler
from Macports (
port install g++-mp-6), you need to set the two flags
cmake -DCMAKE_CXX_COMPILER=/opt/local/bin/g++-mp-6 -DCMAKE_C_COMPILER=/opt/local/bin/gcc-mp-6 ..
Similarly, you can use Homebrew to install clang++ (
brew install llvm) and
then set the two flags to
CMake supports the OpenBLAS and MKL implementations. CMake limitations: the python interface is NOT supported at this point.
Use Faiss as a 3rd-party library: Using Faiss as a 3rd-party lib via CMake is easy.
If the parental project is also build via CMake, just add a line
in CMake where faiss is the sub-folder name. To link Faiss to your application, use
add_executable(my_app my_app.cpp) target_link_libraries(my_app gpufaise faiss)