Add accessors as raw views as an alternative to as_cell_slice when the absence of aliasing views cannot be guaranteed.

Author: adamreichold

src/array.rs

@@ -8,7 +8,8 @@ use std::{
 
 use ndarray::{
     Array, ArrayBase, ArrayView, ArrayViewMut, Axis, Data, Dim, Dimension, IntoDimension, Ix0, Ix1,
-    Ix2, Ix3, Ix4, Ix5, Ix6, IxDyn, RawData, Shape, ShapeBuilder, StrideShape,
+    Ix2, Ix3, Ix4, Ix5, Ix6, IxDyn, RawArrayView, RawArrayViewMut, RawData, Shape, ShapeBuilder,
+    StrideShape,
 };
 use num_traits::AsPrimitive;
 use pyo3::{
@@ -809,7 +810,7 @@ impl<T: Element, D: Dimension> PyArray<T, D> {
         res
     }
 
-    /// Returns the internal array as `ArrayViewMut`. See also [`as_array`](#method.as_array).
+    /// Returns the internal array as [`ArrayViewMut`]. See also [`as_array`](#method.as_array).
     ///
     /// # Safety
     /// If another reference to the internal data exists(e.g., `&[T]` or `ArrayView`),
@@ -821,6 +822,22 @@ impl<T: Element, D: Dimension> PyArray<T, D> {
         res
     }
 
+    /// Returns the internal array as [`RawArrayView`] enabling element access via raw pointers
+    pub fn as_raw_array(&self) -> RawArrayView<T, D> {
+        let (shape, ptr, inverted_axises) = self.ndarray_shape_ptr();
+        let mut res = unsafe { RawArrayView::from_shape_ptr(shape, ptr) };
+        inverted_axises.invert(&mut res);
+        res
+    }
+
+    /// Returns the internal array as [`RawArrayViewMut`] enabling element access via raw pointers
+    pub fn as_raw_array_mut(&self) -> RawArrayViewMut<T, D> {
+        let (shape, ptr, inverted_axises) = self.ndarray_shape_ptr();
+        let mut res = unsafe { RawArrayViewMut::from_shape_ptr(shape, ptr) };
+        inverted_axises.invert(&mut res);
+        res
+    }
+
     /// Get a copy of `PyArray` as
     /// [`ndarray::Array`](https://docs.rs/ndarray/latest/ndarray/type.Array.html).
     ///

tests/array.rs

@@ -96,6 +96,17 @@ fn as_array() {
     })
 }
 
+#[test]
+fn as_raw_array() {
+    pyo3::Python::with_gil(|py| {
+        let not_contiguous = not_contiguous_array(py);
+        let raw_array_view = not_contiguous.as_raw_array();
+        assert_eq!(unsafe { raw_array_view.deref_into_view()[0] }, 1);
+        let raw_array_view_mut = not_contiguous.as_raw_array_mut();
+        assert_eq!(unsafe { raw_array_view_mut.deref_into_view_mut()[1] }, 3);
+    })
+}
+
 #[test]
 fn as_slice() {
     pyo3::Python::with_gil(|py| {