This repo contains the code for the BitFunnel index used by Bing's super-fresh, news, and media indexes. The algorithm is described in BitFunnel: Revisiting Signatures for Search, a paper presented at SIGIR 2017. This video gives a good overview of the algorithm.

The codebase here was published to allow the research community to replicate results from the SIGIR paper. The documentation is pretty thin, but we encourage you to look at the following :

• How to index Wikipedia
• How to play with our query parser
• BitFunnel engineering diary

In order to build BitFunnel you will need CMake (2.8.11+), and a modern C++ compiler (gcc 5+, clang 3.5+, or VC 2015+). You can run CMake directly to generate the appropriate build setup for your platform. Alternately, we have some scripts that have the defaults that we use available.

For *nix platforms (including OS X),

./Configure_Make.sh
cd build-make
make
make test

Note that while these instructions are for a make build, it's also possible to build using ninja by changing the cmake command to create ninja files instead of Makefiles. These aren't listed in the instructions because ninja requires installing an extra dependency for some developers, but if you want to use ninja it's available via apt-get, brew, etc., and is susbtantially faster than make.

If you're on Ubuntu 15+, you can install dependencies with:

sudo apt-get install clang cmake

On Ubuntu 14 and below, you'll need to install a newer version of CMake. To install a new-enough CMake, see this link. If you're using gcc, you'll also need to make sure you have gcc-5 (sudo apt-get install g++-5).

To override the default compiler, set the CXX and CC environment variables. For example, if you have clang-3.8 installed as clang-3.8 and are using bash:

export CXX="clang++-3.8"
export CC="clang-3.8"

Install XCode and then run the following command to install required packages using Homebrew (http://brew.sh/):

brew install cmake

BitFunnel can be built on OS X using either standard *nix makefiles or XCode. In order to generate and build makefiles, in the root BitFunnel directory run:

If you want to create an Xcode project instead of using Makefiles, run:

./Configure_XCode.sh

If you use XCode, you'll have to either re-run Configure_XCode or run the ZERO_CHECK target when the CMakeLists changes, e.g., when source files are added or removed.

You will need these tools:

• CMake (http://www.cmake.org/download/)
• Visual Studio 2017 with C++ compiler (the free version)

Note: If you install Visual Studio for the first time and select the default install options, you won't get a C++ compiler. To force the install of the C++ compiler, you need to either create a new C++ project or open an existing C++ project.

Clone the BitFunnel repository and then run the following command in BitFunnel's root folder:

.\Configure_MSVC.bat

Note: You will need to modify the CMake -G option if you use a different version of Visual Studio. Bitfunnel must be built as a 64-bit program, so 'Win64' must be part of the specified G option text.

At this point, you can open the generated solution BitFunnel_CMake.sln from Visual Studio and then build it. Alternatively, you can build from the command line using cmake --build build-MSVC.