futhark-ffi

Python library using the Futhark C backend via CFFI

Futhark provides several compiler backends, for example futhark opencl which is a C backend, and futhark pyopencl which is a Python backend based on PyOpenCL. However, the host-side code of the Python backend is quite slow, leading to a lot of overhead when small, frequent kernels are used.

A solution to reduce this overhead is to use CFFI to used the C backend from Python, greatly reducing the calling overhead. The OpenCL code is the same, so this is not interesting for long-running kernels.

This library supports the following Futhark backends: c, opencl, multicore, and cuda.

Futhark arrays are mapped to and from Numpy arrays. Multiple outputs and multi-dimensional arrays are supported.

Installation

Install Futhark, then simply

pip install futhark-ffi

Usage

Generate a C library, and build a Python binding for it

futhark opencl --library test.fut
build_futhark_ffi test

Use the Python wrapper

import numpy as np
import _test
from futhark_ffi import Futhark

test = Futhark(_test)
res = test.test3(np.arange(10))
test.from_futhark(res)

Example usage

• https://github.com/mortvest/hastl