rust-numpy

Rust bindings for the NumPy C-API

API documentation

• Latest release (possibly broken)
• Current Master

Requirements

• current nightly rust (see PyO3/pyo3#5 for nightly features, and https://github.com/PyO3/pyo3/blob/master/build.rs for minimum required version)
• 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)

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 2.7, 3.5, 3.6, 3.7 are supported.

By default, rust-numpy is built for Python3.

If you want to compile for Python2, please add a feature flag in Cargo.toml like

[dependencies.numpy]
version = "0.4.0-alpha.1"
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 = "^0.5.0-alpha.2"
numpy = "0.4.0-alpha.1"

extern crate numpy;
extern crate pyo3;
use numpy::{PyArray1, get_array_module};
use pyo3::prelude::{ObjectProtocol, 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 = get_array_module(py)?;
    let dict = PyDict::new(py);
    dict.set_item("np", np)?;
    let pyarray: &PyArray1<i32> = py
        .eval("np.array([1, 2, 3], dtype='int32')", Some(&dict), None)?
        .extract()?;
    let slice = pyarray.as_slice();
    assert_eq!(slice, &[1, 2, 3]);
    Ok(())
}

Write a Python module in Rust

Please see the example directory for a complete example

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

[dependencies]
numpy = "0.4.0-alpha.1"
ndarray = "0.12"

[dependencies.pyo3]
version = "^0.5.0-alpha.2"
features = ["extension-module"]

extern crate ndarray;
extern crate numpy;
extern crate pyo3;

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

#[pymodinit]
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: Python,
        a: f64,
        x: &PyArrayDyn<f64>,
        y: &PyArrayDyn<f64>,
    ) -> PyResult<PyArrayDyn<f64>> {
        // you can convert numpy error into PyErr via ?
        let x = x.as_array();
        // you can also specify your error context, via closure
        let y = y.as_array();
        Ok(axpy(a, x, y).into_pyarray(py).to_owned(py))
    }

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

    Ok(())
}

Contribution

This project is still in pre-alpha. We need your feedback. Don't hesitate to open issues!

Version

• v0.4.0(coming soon)

  • Duplicate PyArrayModule and import Numpy API automatically
  • Fix memory leak of IntoPyArray and add ToPyArray crate
  • PyArray has dimension as type parameter. Now it looks like PyArray<T, D>
  • Use ndarray::IntoDimension to specify dimension
  • Python2 support

• v0.3.1, v0.3.2

  • Just update dependencies

• v0.3.0

  • Breaking Change: Migrated to pyo3 from rust-cpython
  • Some api addition
  • Static type checking with PhantomData

• v0.2.1

  • NEW: trait IntoPyErr, IntoPyResult for error translation

• v0.2.0

  • NEW: traits IntoPyArray, ToPyArray
  • MOD: Interface of PyArray creation functions are changed

• v0.1.1

  • Update documents

• v0.1.0

  • First Release
  • Expose unsafe interfase of Array and UFunc API