ENH: implement may_share_memory in C

memmap needs to call it in __array_finalize__ to determine if it can
drop the references on copies.
The python version if may_share_memory caused significant slowdowns when
slicing these maps.

closes gh-3364

1 files changed, 26 insertions, 0 deletions

diff --git a/numpy/add_newdocs.py b/numpy/add_newdocs.py
index ae07f05da..39dd2205e 100644
--- a/numpy/add_newdocs.py
+++ b/numpy/add_newdocs.py
@@ -3648,6 +3648,32 @@ add_newdoc('numpy.core.multiarray', 'ndarray', ('min',
     """))
 
 
+add_newdoc('numpy.core.multiarray', 'may_share_memory',
+    """
+    Determine if two arrays can share memory
+
+    The memory-bounds of a and b are computed.  If they overlap then
+    this function returns True.  Otherwise, it returns False.
+
+    A return of True does not necessarily mean that the two arrays
+    share any element.  It just means that they *might*.
+
+    Parameters
+    ----------
+    a, b : ndarray
+
+    Returns
+    -------
+    out : bool
+
+    Examples
+    --------
+    >>> np.may_share_memory(np.array([1,2]), np.array([5,8,9]))
+    False
+
+    """)
+
+
 add_newdoc('numpy.core.multiarray', 'ndarray', ('newbyteorder',
     """
     arr.newbyteorder(new_order='S')