IVGCVSW-8055 Add support for GELU activation function.

* Add support to CpuRef, CpuAcc and GpuAcc
* Add support to tflite parser, classic and opaque tflite delegates
* Add support to serializer and deserializer
* Add Unit tests

Signed-off-by: Teresa Charlin <teresa.charlinreyes@arm.com>
Change-Id: Ibc60ef2ef2a051e6d9af6e15d24c46316ec19de4

6 files changed, 75 insertions, 1 deletions

diff --git a/delegate/classic/src/Activation.hpp b/delegate/classic/src/Activation.hpp
index a93cee43a3..1c55c2e9b5 100644
--- a/delegate/classic/src/Activation.hpp
+++ b/delegate/classic/src/Activation.hpp
@@ -109,6 +109,11 @@ TfLiteStatus VisitActivationOperator(DelegateData& delegateData,
             activationDesc.m_A = leakyReluParameters->alpha;
             break;
         }
+        case kTfLiteBuiltinGelu:
+        {
+            activationDesc.m_Function = armnn::ActivationFunction::Gelu;
+            break;
+        }
         default:
         {
             return kTfLiteError;
diff --git a/delegate/classic/src/armnn_delegate.cpp b/delegate/classic/src/armnn_delegate.cpp
index c8f57d6cc3..6054de5c5e 100644
--- a/delegate/classic/src/armnn_delegate.cpp
+++ b/delegate/classic/src/armnn_delegate.cpp
@@ -729,6 +729,12 @@ TfLiteStatus ArmnnSubgraph::VisitNode(DelegateData& delegateData,
                                          tfLiteNode,
                                          nodeIndex,
                                          kTfLiteBuiltinGatherNd);
+        case kTfLiteBuiltinGelu:
+            return VisitActivationOperator(delegateData,
+                                           tfLiteContext,
+                                           tfLiteNode,
+                                           nodeIndex,
+                                           kTfLiteBuiltinGelu);
         case kTfLiteBuiltinGreater:
             return VisitComparisonOperator(delegateData,
                                            tfLiteContext,
diff --git a/delegate/opaque/src/Activation.hpp b/delegate/opaque/src/Activation.hpp
index dd9c2f68bc..ad242e5799 100644
--- a/delegate/opaque/src/Activation.hpp
+++ b/delegate/opaque/src/Activation.hpp
@@ -24,6 +24,9 @@ std::string GetLayerName(armnn::ActivationFunction activationFunction)
         case armnn::ActivationFunction::Elu:
             layerName += " ELU";
             break;
+        case armnn::ActivationFunction::Gelu:
+            layerName += " GELU";
+            break;
         case armnn::ActivationFunction::HardSwish:
             layerName += " HARD_SWISH";
             break;
@@ -175,6 +178,11 @@ TfLiteStatus VisitActivationOperator(DelegateData& delegateData,
             activationDesc.m_A = leakyReluParameters->alpha;
             break;
         }
+        case kTfLiteBuiltinGelu:
+        {
+            activationDesc.m_Function = armnn::ActivationFunction::Gelu;
+            break;
+        }
         default:
         {
             return kTfLiteError;
diff --git a/delegate/opaque/src/armnn_delegate.cpp b/delegate/opaque/src/armnn_delegate.cpp
index 08b1504efb..6abf7398cc 100644
--- a/delegate/opaque/src/armnn_delegate.cpp
+++ b/delegate/opaque/src/armnn_delegate.cpp
@@ -808,6 +808,12 @@ TfLiteStatus ArmnnSubgraph::VisitNode(DelegateData& delegateData,
                                          tfLiteNode,
                                          nodeIndex,
                                          kTfLiteBuiltinGatherNd);
+        case kTfLiteBuiltinGelu:
+            return VisitActivationOperator(delegateData,
+                                           tfLiteContext,
+                                           tfLiteNode,
+                                           nodeIndex,
+                                           kTfLiteBuiltinGelu);
         case kTfLiteBuiltinGreater:
             return VisitComparisonOperator(delegateData,
                                            tfLiteContext,
diff --git a/delegate/test/ActivationTest.cpp b/delegate/test/ActivationTest.cpp
index 620c299803..70321cd7e5 100644
--- a/delegate/test/ActivationTest.cpp
+++ b/delegate/test/ActivationTest.cpp
@@ -196,6 +196,33 @@ void ActivationLeakyReLuTest(std::vector<armnn::BackendId>& backends)
                    alpha);
 }
 
+void ActivationGeluTest(std::vector<armnn::BackendId>& backends)
+{
+    std::vector<float> inputData =
+    {
+        -0.1f, -0.2f, -0.3f, -0.4f,
+         0.1f,  0.2f,  0.3f,  0.4f,
+        -1.0f, -2.0f, -3.0f, -4.0f,
+         1.0f,  2.0f,  3.0f,  4.0f
+    };
+
+    // Calculate output values for input.
+    auto f = [](float x)
+    {
+        // gelu(x) = x * 1/2 * (1 + erf(x / sqrt(2))),
+        // where erf is Gaussian error function
+        auto result = x * (0.5f * (1.0f + erff(static_cast<float>(x / std::sqrt(2)))));
+        return result;
+    };
+    std::vector<float> outputExpectedData(inputData.size());
+    std::transform(inputData.begin(), inputData.end(), outputExpectedData.begin(), f);
+
+    ActivationTest(tflite::BuiltinOperator_GELU,
+                   backends,
+                   inputData,
+                   outputExpectedData);
+}
+
 TEST_SUITE("Activation_CpuRefTests")
 {
 
@@ -241,6 +268,12 @@ TEST_CASE ("Activation_LeakyRelu_CpuRef_Test")
     ActivationLeakyReLuTest(backends);
 }
 
+TEST_CASE ("Activation_Gelu_CpuRef_Test")
+{
+    std::vector<armnn::BackendId> backends = { armnn::Compute::CpuRef };
+    ActivationGeluTest(backends);
+}
+
 }
 
 TEST_SUITE("Activation_CpuAccTests")
@@ -288,6 +321,12 @@ TEST_CASE ("Activation_LeakyRelu_CpuAcc_Test")
     ActivationLeakyReLuTest(backends);
 }
 
+TEST_CASE ("Activation_Gelu_CpuAcc_Test")
+{
+    std::vector<armnn::BackendId> backends = { armnn::Compute::CpuAcc };
+    ActivationGeluTest(backends);
+}
+
 }
 
 TEST_SUITE("Activation_GpuAccTests")
@@ -335,6 +374,12 @@ TEST_CASE ("Activation_LeakyRelu_GpuAcc_Test")
     ActivationLeakyReLuTest(backends);
 }
 
+TEST_CASE ("Activation_Gelu_GpuAcc_Test")
+{
+    std::vector<armnn::BackendId> backends = { armnn::Compute::GpuAcc };
+    ActivationGeluTest(backends);
+}
+
 }
 
 } // namespace armnnDelegate
\ No newline at end of file
diff --git a/delegate/test/ActivationTestHelper.hpp b/delegate/test/ActivationTestHelper.hpp
index b0a4d6785d..7beb53ba3d 100644
--- a/delegate/test/ActivationTestHelper.hpp
+++ b/delegate/test/ActivationTestHelper.hpp
@@ -73,7 +73,11 @@ std::vector<char> CreateActivationTfLiteModel(tflite::BuiltinOperator activation
 
     flatbuffers::Offset <flatbuffers::String> modelDescription =
         flatBufferBuilder.CreateString("ArmnnDelegate: Activation Operator Model");
-    flatbuffers::Offset <OperatorCode> operatorCode = CreateOperatorCode(flatBufferBuilder, activationOperatorCode);
+    flatbuffers::Offset <OperatorCode> operatorCode = CreateOperatorCode(flatBufferBuilder,
+                                                                         activationOperatorCode,
+                                                                         0,
+                                                                         1,
+                                                                         activationOperatorCode);
 
     flatbuffers::Offset <Model> flatbufferModel =
         CreateModel(flatBufferBuilder,