Implement outer for element-wise functions

dpnp/dpnp_algo/dpnp_elementwise_common.py

@@ -341,6 +341,11 @@ def __call__(
                 return out
             return dpnp_array._create_from_usm_ndarray(res_usm)
 
+    def outer(self, x1, x2):
+        _x1 = x1[(Ellipsis,) + (None,) * x2.ndim]
+        _x2 = x2[(None,) * x1.ndim + (Ellipsis,)]
+        return self.__call__(_x1, _x2)
+
 
 class DPNPAngle(DPNPUnaryFunc):
     """Class that implements dpnp.angle unary element-wise functions."""

tests/test_flipping.py

@@ -60,7 +60,7 @@ def test_arange_4d(self, axis, dtype):
     )
     def test_lr_equivalent(self, dtype):
         dp_a = dpnp.arange(4, dtype=dtype)
-        dp_a = dp_a[:, dpnp.newaxis] + dp_a[dpnp.newaxis, :]
+        dp_a = dpnp.add.outer(dp_a, dp_a)
         assert_equal(dpnp.flip(dp_a, 1), dpnp.fliplr(dp_a))
 
         np_a = numpy.arange(4, dtype=dtype)
@@ -72,7 +72,7 @@ def test_lr_equivalent(self, dtype):
     )
     def test_ud_equivalent(self, dtype):
         dp_a = dpnp.arange(4, dtype=dtype)
-        dp_a = dp_a[:, dpnp.newaxis] + dp_a[dpnp.newaxis, :]
+        dp_a = dpnp.add.outer(dp_a, dp_a)
         assert_equal(dpnp.flip(dp_a, 0), dpnp.flipud(dp_a))
 
         np_a = numpy.arange(4, dtype=dtype)

tests/test_mathematical.py

@@ -3142,3 +3142,37 @@ def test_bitwise_1array_input():
     result = dpnp.add(1, x, dtype="f4")
     expected = numpy.add(1, x_np, dtype="f4")
     assert_dtype_allclose(result, expected)
+
+
+@pytest.mark.parametrize(
+    "x_shape",
+    [
+        (),
+        (2),
+        (3, 4),
+        (3, 4, 5),
+    ],
+)
+@pytest.mark.parametrize(
+    "y_shape",
+    [
+        (),
+        (2),
+        (3, 4),
+        (3, 4, 5),
+    ],
+)
+def test_elemenwise_outer(x_shape, y_shape):
+    x_np = numpy.random.random(x_shape)
+    y_np = numpy.random.random(y_shape)
+    expected = numpy.multiply.outer(x_np, y_np)
+
+    x = dpnp.asarray(x_np)
+    y = dpnp.asarray(y_np)
+    result = dpnp.multiply.outer(x, y)
+
+    assert_dtype_allclose(result, expected)
+
+    if x_shape != () and y_shape != ():
+        result_outer = dpnp.outer(x, y)
+        assert dpnp.allclose(result.flatten(), result_outer.flatten())