refine sqrt api check (#20257)

test=release/1.6

python/paddle/fluid/layers/layer_function_generator.py

@@ -22,6 +22,7 @@ from six.moves import cStringIO
 from ..proto import framework_pb2
 from ..framework import OpProtoHolder, Variable, core, convert_np_dtype_to_dtype_
 from ..layer_helper import LayerHelper
+from ..data_feeder import convert_dtype
 
 __all__ = [
     'deprecated', 'generate_layer_fn', 'generate_activation_fn', 'autodoc',
@@ -250,6 +251,18 @@ def generate_activation_fn(op_type):
 
     def func(x, name=None):
         helper = LayerHelper(op_type, **locals())
+        if not isinstance(x, Variable):
+            raise TypeError(
+                "The type of 'x' in %s must be Variable, but received %s" %
+                (op_type, type(x)))
+        if convert_dtype(x.dtype) in ['float16']:
+            warnings.warn(
+                "The data type of 'x' in %s only support float16 in GPU now." %
+                (op_type))
+        if convert_dtype(x.dtype) not in ['float16', 'float32', 'float64']:
+            raise TypeError(
+                "The data type of 'x' in %s must be float16 (only support on GPU), float32 or float64, but received %s."
+                % (op_type, convert_dtype(x.dtype)))
         output = helper.create_variable_for_type_inference(dtype=x.dtype)
         helper.append_op(type=op_type, inputs={"X": x}, outputs={"Out": output})
         return output

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

@@ -23,6 +23,22 @@ import paddle.fluid as fluid
 from paddle.fluid import compiler, Program, program_guard
 
 
+class TestSqrtOpError(OpTest):
+    def test_errors(self):
+        with program_guard(Program(), Program()):
+            # The input type of sqrt_op must be Variable or numpy.ndarray.
+            in1 = 1
+            self.assertRaises(TypeError, fluid.layers.sqrt, in1)
+            # The input dtype of sqrt_op must be float16, float32, float64.
+            in2 = fluid.layers.data(
+                name='input2', shape=[12, 10], dtype="int32")
+            self.assertRaises(TypeError, fluid.layers.sqrt, in2)
+
+            in3 = fluid.layers.data(
+                name='input3', shape=[12, 10], dtype="float16")
+            fluid.layers.sqrt(x=in3)
+
+
 class TestActivation(OpTest):
     def setUp(self):
         self.op_type = "exp"