[fp16] suppot fp16 in tensordot (#50938)

* fix fp16 bug of tensordot

* fix fp16 of tensordot

* fix fp16 of tensordot

python/paddle/fluid/tests/unittests/test_tensordot.py

@@ -224,6 +224,33 @@ class TestTensordotAPI(unittest.TestCase):
                     np_res = tensordot_np(self.x, self.y, axes)
                     np.testing.assert_allclose(paddle_res[0], np_res, rtol=1e-6)
 
+    def test_fp16_with_gpu(self):
+        paddle.enable_static()
+        if paddle.fluid.core.is_compiled_with_cuda():
+            for axes in self.all_axes:
+                place = paddle.CUDAPlace(0)
+                with paddle.static.program_guard(
+                    paddle.static.Program(), paddle.static.Program()
+                ):
+                    input_x = np.random.random([5, 5, 5, 5]).astype("float16")
+                    x = paddle.static.data(
+                        name="x", shape=[5, 5, 5, 5], dtype="float16"
+                    )
+
+                    input_y = np.random.random([5, 5, 5, 5]).astype("float16")
+                    y = paddle.static.data(
+                        name="y", shape=[5, 5, 5, 5], dtype="float16"
+                    )
+
+                    z = paddle.tensordot(x, y, axes)
+                    exe = paddle.static.Executor(place)
+
+                    paddle_res = exe.run(
+                        feed={'x': input_x, 'y': input_y}, fetch_list=[z]
+                    )
+                    np_res = tensordot_np(input_x, input_y, axes)
+                    np.testing.assert_allclose(paddle_res[0], np_res, rtol=1)
+
 
 class TestTensordotAPIFloat64(TestTensordotAPI):
     def set_dtype(self):

python/paddle/tensor/manipulation.py

@@ -3940,7 +3940,7 @@ def tensordot(x, y, axes=2, name=None):
     This function computes a contraction, which sum the product of elements from two tensors along the given axes.
 
     Args:
-        x (Tensor): The left tensor for contraction with data type ``float32`` or ``float64``.
+        x (Tensor): The left tensor for contraction with data type ``float16`` or ``float32`` or ``float64``.
         y (Tensor): The right tensor for contraction with the same data type as ``x``.
         axes (int|tuple|list|Tensor, optional):  The axes to contract for ``x`` and ``y``, defaulted to integer ``2``.
 
@@ -4048,7 +4048,7 @@ def tensordot(x, y, axes=2, name=None):
             #      [28312230., 30496530., 32680830., 34865130.]]
     """
     op_type = 'tensordot'
-    input_dtype = ['float32', 'float64']
+    input_dtype = ['float16', 'float32', 'float64']
 
     check_variable_and_dtype(x, 'x', input_dtype, op_type)
     check_variable_and_dtype(y, 'y', input_dtype, op_type)