ProxyObject to support matrix multiplication (#849)

Implements `ProxyObject.__matmul__` and `ProxyObject.__imatmul__`.

@pentschev can you check if this fixes #843 (comment)

Authors:
  - Mads R. B. Kristensen (https://github.com/madsbk)

Approvers:
  - Peter Andreas Entschev (https://github.com/pentschev)

URL: #849

dask_cuda/proxy_object.py

@@ -619,6 +619,9 @@ def __xor__(self, other):
     def __or__(self, other):
         return self._pxy_deserialize() | other
 
+    def __matmul__(self, other):
+        return self._pxy_deserialize().__matmul__(unproxy(other))
+
     def __radd__(self, other):
         return other + self._pxy_deserialize()
 
@@ -741,6 +744,14 @@ def __ior__(self, other):
         self._pxy_set(pxy)
         return self
 
+    def __imatmul__(self, other):
+        pxy = self._pxy_get(copy=True)
+        proxied = pxy.deserialize(nbytes=self.__sizeof__())
+        proxied @= other
+        pxy.obj = proxied
+        self._pxy_set(pxy)
+        return self
+
     def __neg__(self):
         return -self._pxy_deserialize()
 

dask_cuda/tests/test_proxy.py

@@ -620,3 +620,27 @@ def test_cupy_broadcast_to():
 
     assert a_b.shape == p_b.shape
     assert (a_b == p_b).all()
+
+
+def test_cupy_matmul():
+    cupy = pytest.importorskip("cupy")
+    a, b = cupy.arange(10), cupy.arange(10)
+    c = a @ b
+    assert c == proxy_object.asproxy(a) @ b
+    assert c == a @ proxy_object.asproxy(b)
+    assert c == proxy_object.asproxy(a) @ proxy_object.asproxy(b)
+
+
+def test_cupy_imatmul():
+    cupy = pytest.importorskip("cupy")
+    a = cupy.arange(9).reshape(3, 3)
+    c = a.copy()
+    c @= a
+
+    a1 = a.copy()
+    a1 @= proxy_object.asproxy(a)
+    assert (a1 == c).all()
+
+    a2 = proxy_object.asproxy(a.copy())
+    a2 @= a
+    assert (a2 == c).all()