add input type and dtype check for elu_op (#20106)

* elu input check
test=develop

* test=develop

python/paddle/fluid/layers/nn.py

@@ -10883,6 +10883,17 @@ def elu(x, alpha=1.0, name=None):
             y = fluid.layers.elu(x, alpha=0.2)
     """
     helper = LayerHelper('elu', **locals())
+    if not isinstance(x, Variable):
+        raise TypeError(
+            "The type of 'x' in elu must be Variable, but received %s" %
+            (type(x)))
+    if convert_dtype(x.dtype) in ['float16']:
+        warnings.warn(
+            "The data type of 'x' in elu only support float16 in GPU now.")
+    if convert_dtype(x.dtype) not in ['float16', 'float32', 'float64']:
+        raise TypeError(
+            "The data type of 'x' in elu must be float16 (only support on GPU), float32 or float64, but received %s."
+            % (convert_dtype(x.dtype)))
     out = helper.create_variable_for_type_inference(dtype=x.dtype)
     helper.append_op(
         type='elu',

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

@@ -19,6 +19,8 @@ import numpy as np
 import paddle.fluid.core as core
 from op_test import OpTest
 from scipy.special import expit, erf
+import paddle.fluid as fluid
+from paddle.fluid import compiler, Program, program_guard
 
 
 class TestActivation(OpTest):
@@ -519,6 +521,18 @@ class TestELU(TestActivation):
         self.check_grad(['X'], 'Out', max_relative_error=0.02)
 
 
+class TestELUOpError(OpTest):
+    def test_errors(self):
+        with program_guard(Program(), Program()):
+            # The input type of elu_op must be Variable.
+            x1 = fluid.create_lod_tensor(
+                np.array([[-1]]), [[1]], fluid.CPUPlace())
+            self.assertRaises(TypeError, fluid.layers.elu, x1)
+            # The input dtype of elu_op must be float16 float32 or float64.
+            x2 = fluid.layers.data(name='x2', shape=[4], dtype="int32")
+            self.assertRaises(TypeError, fluid.layers.elu, x2)
+
+
 class TestReciprocal(TestActivation):
     def setUp(self):
         self.op_type = "reciprocal"