Grafite

Grafite is a data structure that enables fast range emptiness queries using optimal space and time. It provides strong guarantees on the expected false positive rate under any kind of workloads.

Paper | A³ Lab

Quickstart

This is a header-only library. It does not need to be installed. Just clone the repo with

git clone https://github.com/marcocosta97/grafite.git
cd grafite
git submodule update --init lib/sux

and copy the include/grafite and lib/sux directories to your system's or project's include path.

The examples/simple.cpp file shows how to index and query a vector of random integers with Grafite:

#include <iostream>
#include <vector>
#include <algorithm>
#include "grafite/grafite.hpp"

int main()
{
    std::vector<int> keys (1000000);
    std::generate(keys.begin(), keys.end(), std::rand);
    keys.push_back(42);

    // Construct the Grafite range filter
    auto bpk = 12.0;
    auto g = grafite::filter(keys.begin(), keys.end(), bpk);

    // Query the Grafite range filter
    auto left = 40, right = 44;
    auto result = g.query(left, right);
    std::cout << "Query result: " << result << std::endl;

    return 0;
}

Run and edit this and other examples on Repl.it. Or run it locally via:

g++ examples/simple.cpp -std=c++17 -I./include -I./lib/sux -DSUCCINCT_LIB_SUX -o simple
./simple

Classes overview

Other than the grafite::filter class in the example above, this library provides the following classes:

• grafite::bucket an heuristic range filter which provides very fast lookups in small space without any guarantee on the false positive rate.
• grafite::ef_sux_vector a wrapper for the Elias-Fano implementation of the sux library. This implementation is used by default from Grafite.
• grafite::ef_sdsl_vector a wrapper for the Elias-Fano implementation of the sdsl library.

Compile the tests and the benchmarks

After cloning the repository and all its submodules with

git clone --recurse-submodules -j8 https://github.com/marcocosta97/grafite.git
cd grafite

build the project with CMAKE

mkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make -j8

The benchmarks will be placed in build/bench/, see reproducibility.md for details on how to reproduce the tests in the paper.

License

This project is licensed under the GPLv3 License - see the LICENSE file for details.