Enable square operator for the nGraph Bridge. (#17551)

test=develop

paddle/fluid/operators/ngraph/ops/activation_op.h

@@ -37,6 +37,16 @@ void BuildReluGradNode(
   platform::SetOutputNode(op, "X@GRAD", relu_grad, ngb_node_map);
 }
 
+void BuildSquareNode(
+    const std::shared_ptr<framework::OperatorBase>& op,
+    std::shared_ptr<
+        std::unordered_map<std::string, std::shared_ptr<ngraph::Node>>>
+        ngb_node_map) {
+  auto input = platform::GetInputNode(op, "X", ngb_node_map);
+  auto out = input * input;
+  platform::SetOutputNode(op, "Out", out, ngb_node_map);
+}
+
 void BuildTanhGradNode(
     const std::shared_ptr<framework::OperatorBase>& op,
     std::shared_ptr<
@@ -55,4 +65,5 @@ void BuildTanhGradNode(
 }  // namespace paddle
 
 REGISTER_NG_OP(relu_grad, BuildReluGradNode);
+REGISTER_NG_OP(square, BuildSquareNode);
 REGISTER_NG_OP(tanh_grad, BuildTanhGradNode);

python/paddle/fluid/tests/unittests/ngraph/test_activation_ngraph_op.py

@@ -18,7 +18,7 @@ import unittest
 import numpy as np
 import paddle.fluid.core as core
 from paddle.fluid.tests.unittests.op_test import OpTest
-from paddle.fluid.tests.unittests.test_activation_op import TestAbs, TestSigmoid, TestRelu, TestTanh
+from paddle.fluid.tests.unittests.test_activation_op import TestAbs, TestSigmoid, TestSquare, TestRelu, TestTanh
 
 
 class TestNGRAPHReluDim4(TestRelu):