rust-numpy

Rust bindings for the NumPy C-API

API documentation

Requirements

Rust 1.39+
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.

Supported Python version

Currently 3.5, 3.6, 3.7, and 3.8 are supported.

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 = "0.11.1"
numpy = "0.11.0"

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

fn main() -> Result<(), ()> {
    let gil = Python::acquire_gil();
    main_(gil.python()).map_err(|e| {
        eprintln!("error! :{:?}", e);
        // we can't display python error type via ::std::fmt::Display
        // so print error here manually
        e.print_and_set_sys_last_vars(gil.python());
    })
}

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

Write a Python module in Rust

Please see the examples directory for a complete example

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

[dependencies]
numpy = "0.11.0"
ndarray = "0.13"

[dependencies.pyo3]
version = "0.11.1"
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(())
}

Contribution

We need your feedback.

Don't hesitate to open issues!

n1t0/rust-numpy