Merge pull request #1 from user01/feature/expose-mask-to-python

Feature/expose mask to python

Author: user01

Cargo.lock

@@ -1,10 +1,11 @@
 [package]
 name = "rdp-rust"
-version = "0.4.0"
+version = "0.5.0"
 edition = "2018"
 authors = ["[email protected]"]
 license = "MIT"
 readme = "README.md"
+url = "https://github.com/user01/rdp-rust"
 
 [lib]
 name = "rdp_rust"

Cargo.toml

@@ -5,7 +5,7 @@ build:
 test: clean install
 	cargo test --no-default-features
 	cargo bench
-	pytest -q test_options.py --benchmark-group-by=group
+	pytest -q test_options.py
 
 target/wheels/rdp_rust-*-cp37-cp37m-macosx_10_7_x86_64.whl:
 	maturin build --release

Makefile

@@ -32,6 +32,15 @@ array([[5., 0.],
        [3., 2.]])
 ```
 
+```python
+>>> import numpy as np
+>>> from rdp_rust import mask_points
+
+>>> arr = np.array([5.0, 0, 4, 0, 3, 0, 3, 1, 3, 2]).reshape(5, 2)
+>>> mask_points(small_arr, 0.2)
+array([ True, False,  True, False,  True])
+```
+
 ## Example
 
 ![Demo of RDP](https://github.com/user01/rdp-rust/raw/master/rdp-demo.gif "Demo of RDP")

README.md

@@ -10,6 +10,7 @@ use pyo3::prelude::{pymodule, Py, PyModule, PyResult, Python};
 #[allow(unused_imports)]
 use pyo3::{IntoPy, PyObject, ToPyObject};
 use pyo3::exceptions;
+use ndarray::Array;
 
 mod rdp;
 
@@ -49,10 +50,53 @@ fn reduce_points(
     }
 }
 
+/// mask_points(points, epsilon, /)
+/// --
+///
+/// Provide the mask for the RDP point reduction on the float64
+/// numpy array of points
+/// points must be a numpy array of n by d, where n is the number
+/// of points and d is the dimension.
+/// Epsilon (float) is the threshold where points are removed as
+/// irrelevant, as defined by euclidean distance in the d
+/// dimensional space
+/// Makes use of the Ramer-Douglas-Peucker algorithm
+/// https://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93Peucker_algorithm
+#[pyfunction]
+fn mask_points(
+    py: Python,
+    points: &PyArrayDyn<f64>,
+    epsilon: f64,
+) -> PyResult<Py<PyArrayDyn<bool>>> {
+    let the_points = points.as_array().to_owned();
+    let dims = &the_points.shape().len();
+    if *dims != 2 {
+        Err(
+            exceptions::ValueError::py_err("Incorrect shape. Must be numpy floating of n points by d dimension")
+        )
+    } else if epsilon < 0.0 {
+        Err(
+            exceptions::ValueError::py_err("Epsilon must be a float greater than 0")
+        )
+    } else {
+        let indices = rdp::iter(&the_points, epsilon);
+        let result = Array::from_shape_vec(
+            indices.len(),
+            indices,
+        ).expect(
+            "Unable to build"
+        );
+        Ok(
+            result.into_dyn().into_pyarray(py).to_owned()
+        )
+    }
+}
+
 
 #[pymodule]
 fn rdp_rust(_py: Python, m: &PyModule) -> PyResult<()> {
     m.add_wrapped(wrap_pyfunction!(reduce_points))?;
+    m.add_wrapped(wrap_pyfunction!(mask_points))?;
 
     Ok(())
 }

src/lib.rs

@@ -1,5 +1,6 @@
-import numpy as np
 import pytest
+
+import numpy as np
 import rdp_rust
 from rdp import rdp
 
@@ -19,6 +20,13 @@ def test_basic():
     assert res_rs.shape == res_py.shape
     np.testing.assert_almost_equal(res_rs, res_py)
 
+def test_basic_mask():
+    arr = np.array([5.0, 0, 4, 0, 3, 0, 3, 1, 3, 2]).reshape(5, 2)
+    res_rs = rdp_rust.mask_points(arr, 0.1)
+    res_py = rdp(arr, 0.1, return_mask=True)
+    assert res_rs.shape == res_py.shape
+    np.testing.assert_almost_equal(res_rs, res_py)
+
 
 small_arr = np.array([5.0, 0, 4, 0, 3, 0, 3, 1, 3, 2]).reshape(5, 2)
 small_expected = np.array([5.0, 0, 3, 0, 3, 2.0]).reshape(3, 2)