rust-numpy

Rust bindings for the NumPy C-API

API documentation

• Latest release (possibly broken)
• Current Master

Requirements

• Rust 1.39+
• Python >= 3.6
  • Python 3.5 support is dropped from 0.13
• Some Rust libraries
  • ndarray for rust-side matrix library
  • pyo3 for cpython binding
  • and more (see Cargo.toml)
• numpy installed in your python environments (e.g., via pip install numpy)
  • We recommend numpy >= 1.16.0, though older version may work.

Note Starting from 0.3, rust-numpy migrated from rust-cpython to pyo3. If you want to use rust-cpython, use version 0.2.1 from crates.io.

Python2 Support

Version 0.5.0 is the last version that supports Python2.

If you want to compile this library with Python2, please use 0.5.0 from crates.io.

In addition, you have to add a feature flag in Cargo.toml like

[dependencies.numpy]
version = "0.5.0"
features = ["python2"]

.

You can also automatically specify python version in setup.py, using setuptools-rust.

Example

Execute a Python program from Rust and get results

[package]
name = "numpy-test"

[dependencies]
pyo3 = "0.13"
numpy = "0.13"

use numpy::PyArray1;
use pyo3::prelude::{PyResult, Python};
use pyo3::types::IntoPyDict;

fn main() -> PyResult<()> {
    Python::with_gil(|py| {
        let np = py.import("numpy")?;
        let locals = [("np", np)].into_py_dict(py);
        let pyarray: &PyArray1<i32> = py
            .eval("np.absolute(np.array([-1, -2, -3], dtype='int32'))", Some(locals), None)?
            .extract()?;
        let readonly = pyarray.readonly();
        let slice = readonly.as_slice()?;
        assert_eq!(slice, &[1, 2, 3]);
        Ok(())
    })
}

Write a Python module in Rust

Please see simple-extension directory for the complete example. Also, we have an example project with ndarray-linalg.

[lib]
name = "rust_ext"
crate-type = ["cdylib"]

[dependencies]
numpy = "0.13"
ndarray = "0.14"

[dependencies.pyo3]
version = "0.13"
features = ["extension-module"]

use ndarray::{ArrayD, ArrayViewD, ArrayViewMutD};
use numpy::{IntoPyArray, PyArrayDyn, PyReadonlyArrayDyn};
use pyo3::prelude::{pymodule, PyModule, PyResult, Python};

#[pymodule]
fn rust_ext(_py: Python<'_>, m: &PyModule) -> PyResult<()> {
    // immutable example
    fn axpy(a: f64, x: ArrayViewD<'_, f64>, y: ArrayViewD<'_, f64>) -> ArrayD<f64> {
        a * &x + &y
    }

    // mutable example (no return)
    fn mult(a: f64, mut x: ArrayViewMutD<'_, f64>) {
        x *= a;
    }

    // wrapper of `axpy`
    #[pyfn(m, "axpy")]
    fn axpy_py<'py>(
        py: Python<'py>,
        a: f64,
        x: PyReadonlyArrayDyn<f64>,
        y: PyReadonlyArrayDyn<f64>,
    ) -> &'py PyArrayDyn<f64> {
        let x = x.as_array();
        let y = y.as_array();
        axpy(a, x, y).into_pyarray(py)
    }

    // wrapper of `mult`
    #[pyfn(m, "mult")]
    fn mult_py(_py: Python<'_>, a: f64, x: &PyArrayDyn<f64>) -> PyResult<()> {
        let x = unsafe { x.as_array_mut() };
        mult(a, x);
        Ok(())
    }

    Ok(())
}

Conributing

We welcome issues and pull requests.

PyO3's contrinbuting.md is a nice guide for starting. Also, we have a gitter channel for communicating.