Add float16 to less than (#51145)

* add float16 to less_than

* Modify the function title

* update

* update

* update  solve PR-CI-Kunlun-KP-Build

* update codestyle

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

+#   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+import unittest
+
+import numpy as np
+
+import paddle
+import paddle.fluid.core as core
+import paddle.static as static
+
+
+class Test_Less_Than_Op_Fp16(unittest.TestCase):
+    def test_api_fp16(self):
+        paddle.enable_static()
+        with static.program_guard(static.Program(), static.Program()):
+            label = paddle.to_tensor([3, 3], dtype="float16")
+            limit = paddle.to_tensor([3, 2], dtype="float16")
+            out = paddle.less_than(x=label, y=limit)
+            if core.is_compiled_with_cuda():
+                place = paddle.CUDAPlace(0)
+                exe = static.Executor(place)
+                (res,) = exe.run(fetch_list=[out])
+                self.assertEqual((res == np.array([False, False])).all(), True)
+
+
+if __name__ == '__main__':
+    paddle.enable_static()
+    unittest.main()

python/paddle/tensor/logic.py

@@ -655,8 +655,8 @@ def less_than(x, y, name=None):
         The output has no gradient.
 
     Args:
-        x(Tensor): First input to compare which is N-D tensor. The input data type should be bool, float32, float64, int32, int64.
-        y(Tensor): Second input to compare which is N-D tensor. The input data type should be bool, float32, float64, int32, int64.
+        x(Tensor): First input to compare which is N-D tensor. The input data type should be bool, float16, float32, float64, int32, int64.
+        y(Tensor): Second input to compare which is N-D tensor. The input data type should be bool, float16, float32, float64, int32, int64.
         name(str, optional): The default value is None.  Normally there is no need for
             user to set this property.  For more information, please refer to :ref:`api_guide_Name`.
 
@@ -679,13 +679,13 @@ def less_than(x, y, name=None):
         check_variable_and_dtype(
             x,
             "x",
-            ["bool", "float32", "float64", "int32", "int64"],
+            ["bool", "float16", "float32", "float64", "int32", "int64"],
             "less_than",
         )
         check_variable_and_dtype(
             y,
             "y",
-            ["bool", "float32", "float64", "int32", "int64"],
+            ["bool", "float16", "float32", "float64", "int32", "int64"],
             "less_than",
         )
         helper = LayerHelper("less_than", **locals())