Add ndarray-linalg example (#88)

* Add linalg example

* Shorten discription for flake8

* Add gfortran to travis deps

* Use travis_wait

Author: kngwyu

.travis.yml

@@ -34,6 +34,7 @@ addons:
       - gcc
       - binutils-dev
       - libiberty-dev
+      - gfortran
 
 before_install:
   - source ./ci/travis/setup.sh
@@ -44,7 +45,7 @@ install:
 
 script:
   - flake8 examples/
-  - ./ci/travis/test.sh
+  - travis_wait ./ci/travis/test.sh
 
 deploy:
   - provider: script

examples/linalg/Cargo.toml

@@ -0,0 +1,18 @@
+[package]
+name = "numpy-linalg-example"
+version = "0.1.0"
+authors = ["kngwyu <[email protected]>"]
+edition = "2018"
+
+[lib]
+name = "rust_linalg"
+crate-type = ["cdylib"]
+
+[dependencies]
+numpy = { path = "../.." }
+ndarray = "0.12"
+ndarray-linalg = { version = "0.10", features = ["openblas"] }
+
+[dependencies.pyo3]
+version = "0.5.2"
+features = ["extension-module"]

examples/linalg/requirements-dev.txt

@@ -0,0 +1,3 @@
+numpy>=1.15.0
+pytest>=3.5.0
+setuptools-rust>=0.10.2

examples/linalg/rust_linalg/__init__.py

@@ -0,0 +1 @@
+from .rust_linalg import *  # noqa

examples/linalg/setup.py

@@ -0,0 +1,27 @@
+import sys
+from setuptools import find_packages, setup
+from setuptools_rust import RustExtension
+
+
+PYTHON_MAJOR_VERSION = sys.version_info[0]
+
+setup_requires = ['setuptools-rust>=0.6.0']
+install_requires = ['numpy']
+test_requires = install_requires + ['pytest']
+
+setup(
+    name='rust_linalg',
+    version='0.1.0',
+    description='Example of python extension with ndarray-linalg',
+    rust_extensions=[RustExtension(
+        'rust_linalg.rust_linalg',
+        './Cargo.toml',
+        rustc_flags=['--cfg=Py_{}'.format(PYTHON_MAJOR_VERSION)],
+        features=['numpy/python{}'.format(PYTHON_MAJOR_VERSION)],
+    )],
+    install_requires=install_requires,
+    setup_requires=setup_requires,
+    test_requires=test_requires,
+    packages=find_packages(),
+    zip_safe=False,
+)

examples/linalg/src/lib.rs

@@ -0,0 +1,19 @@
+use ndarray_linalg::solve::Inverse;
+use numpy::{IntoPyArray, PyArray2};
+use pyo3::exceptions::RuntimeError;
+use pyo3::prelude::{pymodinit, Py, PyErr, PyModule, PyResult, Python};
+use std::fmt::Display;
+
+fn make_error<E: Display + Sized>(e: E) -> PyErr {
+    PyErr::new::<RuntimeError, _>(format!("[rust_linalg] {}", e))
+}
+
+#[pymodinit]
+fn rust_linalg(_py: Python, m: &PyModule) -> PyResult<()> {
+    #[pyfn(m, "inv")]
+    fn inv(py: Python, x: &PyArray2<f64>) -> PyResult<Py<PyArray2<f64>>> {
+        let x = x.as_array().inv().map_err(make_error)?;
+        Ok(x.into_pyarray(py).to_owned())
+    }
+    Ok(())
+}

examples/linalg/tests/test_linalg.py

@@ -0,0 +1,11 @@
+import numpy as np
+import rust_linalg
+
+
+def test_inv():
+    x = np.array([
+        [1, 0],
+        [0, 2],
+    ], dtype=np.float64)
+    y = rust_linalg.inv(x)
+    np.testing.assert_array_almost_equal(y, np.linalg.inv(x))

examples/linalg/tox.ini

@@ -0,0 +1,13 @@
+[tox]
+envlist = py27,
+          py35,
+          py36,
+          py37,
+minversion = 2.9.0
+skip_missing_interpreters = true
+
+[testenv]
+description = Run the unit tests under {basepython}
+deps = -rrequirements-dev.txt
+usedevelop = True
+commands = pytest