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✓ Uses Rust 2018 edition

0.9.2 Jun 25, 2020
0.8.0 May 13, 2020
0.6.4 Mar 2, 2020
0.5.2 Dec 17, 2019
0.2.0 May 20, 2019
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Used in 13 crates (7 directly)


10K SLoC

bellperson Crates.io

This is a fork of the great bellman library.

bellman is a crate for building zk-SNARK circuits. It provides circuit traits and primitive structures, as well as basic gadget implementations such as booleans and number abstractions.


This fork contains GPU parallel acceleration to the FFT and Multiexponentation algorithms in the groth16 prover codebase under a conditional compilation feature #[cfg(feature = "gpu")] and gpu-test for testing.


  • NVIDIA GPU Graphics Driver

  • OpenCL

Environment variables

The gpu extension contains some env vars that may be set externally to this library.


Will disable the GPU feature from the library and force usage of the CPU.

env::set_var("BELLMAN_NO_GPU", "1");


Will allow for adding a GPU not in the tested list. This requires researching the name of the GPU device and the number of cores in the format ["name:cores"].

env::set_var("BELLMAN_CUSTOM_GPU", "GeForce RTX 2080 Ti:4352, GeForce GTX 1060:1280");


Can be set in the interval [0,1] to designate a proportion of the multiexponenation calculation to be moved to cpu in parallel to the GPU to keep all hardware occupied.

env::set_var("BELLMAN_CPU_UTILIZATION", "0.5");


Chooses the device in which the batched verifier is going to run. Can be cpu, gpu or auto.

env::set_var("BELLMAN_VERIFIER", "gpu");

Supported / Tested Cards

Currently only Nvidia hardware is supported, see issue. Depending on the size of the proof being passed to the gpu for work, certain cards will not be able to allocate enough memory to either the FFT or Multiexp kernel. Below are a list of devices that work for small sets. In the future we will add the cuttoff point at which a given card will not be able to allocate enough memory to utilize the GPU.

("Device_Name", Cores),
("Quadro RTX 6000", 4608),
("TITAN RTX", 4608),
("Tesla V100", 5120),
("Tesla P100", 3584),
("Tesla T4", 2560),
("Quadro M5000", 2048),
("GeForce RTX 2080 Ti", 4352),
("GeForce RTX 2080 SUPER", 3072),
("GeForce RTX 2080", 2944),
("GeForce RTX 2070 SUPER", 2560),
("GeForce GTX 1080 Ti", 3584),
("GeForce GTX 1080", 2560),
("GeForce GTX 2060", 1920),
("GeForce GTX 1660 Ti", 1536),
("GeForce GTX 1060", 1280),
("GeForce GTX 1650 SUPER", 1280),
("GeForce GTX 1650", 896),


Licensed under either of

at your option.


Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.


~67K SLoC