pybindings for nalgebra or other matrix math libs

[sjbeskur]

I'm able to expose simple functions written in Rust to python using pyo3 but can see no way to expose complex "eigen" / matrix types. Does anyone know if this is possible? I was hoping it would work like the pybind11 stuff in C++ that includes eigen vector / matrix types.

lib.rs

extern crate nalgebra as na;    
use pyo3::prelude::*;
use na::{SMatrix, Vector3, Matrix3};

/// Formats the sum of two numbers as string.
#[pyfunction]
fn sum_as_string(a: usize, b: usize) -> PyResult<String> {
    Ok((a + b).to_string())
}


#[pyfunction]
fn matrix_math(v3: Vector3<f64>, m3x3: Matrix3<f64>) -> PyResult<SMatrix<f64, 3, 1>>{
    let mxv = m3x3 * v3;
    Ok(mxv)
}

// Neiter way works

type Matrix3f = Matrix3<f64>;
type Vector3f = Vector3<f64>;

#[pyfunction]
fn matrix_math_w_types(v3: Vector3f, m3x3: Matrix3f) -> PyResult<SMatrix<f64, 3, 1>>{
    let mxv = m3x3 * v3;
    mxv
}

#[pymodule]
fn libpytest(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_function(wrap_pyfunction!(sum_as_string, m)?)?;
    m.add_function(wrap_pyfunction!(matrix_math, m)?)?;

    Ok(())
}

[adamreichold]

I think rust-numpy which provides glue between Python's NumPy and Rust's ndarray might be helpful in this case?

[davidhewitt]

To add to this, if you want to use nalgebra instead of ndarray a pull request to rust-numpy adding an optional feature is welcome!

[sjbeskur]

@adamreichold , @davidhewitt Thanks. I had not explored ndarray but will look into this. nalgebra just had such great documentation I thought it might be the rust matrix math defacto. Will definitely look into ndarray and rust-numpy.