IVGCVSW-4439: Adding Elu support to Activation

 * Added CpuRef implementation
 * Added Unit Tests
 * Added Quantizer Test
 * Enabled Tests for Neon and CL backends on fp32 only
 * Added to Serializer

Signed-off-by: David Monahan <david.monahan@arm.com>
Change-Id: Ic23e1797dbc9352b40678c389d7fe2b836b582ea

8 files changed, 91 insertions, 0 deletions

diff --git a/src/backends/aclCommon/ArmComputeUtils.hpp b/src/backends/aclCommon/ArmComputeUtils.hpp
index 4d690901c6..01a5445844 100644
--- a/src/backends/aclCommon/ArmComputeUtils.hpp
+++ b/src/backends/aclCommon/ArmComputeUtils.hpp
@@ -65,6 +65,7 @@ ConvertActivationFunctionToAclActivationFunction(ActivationFunction armnnFunctio
         case ActivationFunction::Sqrt:          return AclActivationFunction::SQRT;
         case ActivationFunction::Square:        return AclActivationFunction::SQUARE;
         case ActivationFunction::TanH:          return AclActivationFunction::TANH;
+        case ActivationFunction::Elu:           return AclActivationFunction::ELU;
         default:                                throw InvalidArgumentException("Unsupported activation function");
     }
 }
diff --git a/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.cpp b/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.cpp
index 3f5e6c39e3..1b6e782060 100644
--- a/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.cpp
+++ b/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.cpp
@@ -1016,6 +1016,64 @@ LayerTestResult<int16_t, 4> TanhInt16Test(
 }
 
 
+template<armnn::DataType ArmnnType, typename T = armnn::ResolveType<ArmnnType>>
+LayerTestResult<T, 4> EluTestCommon(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager,
+        float qScale,
+        int32_t qOffset)
+{
+    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
+    };
+
+
+    const float a = 0.01f;
+    // Calculate output values for input.
+    auto f = [a](float value)
+    {
+        return (value >= 0) ? value : a * (expf(value) - 1);
+    };
+    std::vector<float> outputExpectedData(inputData.size());
+    std::transform(inputData.begin(), inputData.end(), outputExpectedData.begin(), f);
+
+    return SimpleActivationTest<ArmnnType>(workloadFactory,
+                                           memoryManager,
+                                           armnn::ActivationFunction::Elu,
+                                           a,
+                                           0.0f,
+                                           qScale,
+                                           qOffset,
+                                           inputData,
+                                           qScale,
+                                           qOffset,
+                                           outputExpectedData);
+}
+
+LayerTestResult<float, 4> EluTest(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager)
+{
+    return EluTestCommon<armnn::DataType::Float32>(workloadFactory, memoryManager, 0.1f, 0);
+}
+
+LayerTestResult<uint8_t, 4> EluUint8Test(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager)
+{
+    return EluTestCommon<armnn::DataType::QAsymmU8>(workloadFactory, memoryManager, 0.1f, 64);
+}
+
+LayerTestResult<int16_t, 4> EluInt16Test(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager)
+{
+    return EluTestCommon<armnn::DataType::QSymmS16>(workloadFactory, memoryManager, 0.1f, 0);
+}
+
 
 template<armnn::DataType ArmnnType, typename T = armnn::ResolveType<ArmnnType>>
 LayerTestResult<T,4> CompareActivationTestImpl(
diff --git a/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.hpp b/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.hpp
index 2251ceb8dd..28301188d5 100644
--- a/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.hpp
+++ b/src/backends/backendsCommon/test/layerTests/ActivationTestImpl.hpp
@@ -149,6 +149,22 @@ LayerTestResult<int16_t, 4> LeakyReLuInt16Test(
         const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager);
 
 //
+// Elu
+//
+
+LayerTestResult<float, 4> EluTest(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager);
+
+LayerTestResult<uint8_t, 4> EluUint8Test(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager);
+
+LayerTestResult<int16_t, 4> EluInt16Test(
+        armnn::IWorkloadFactory& workloadFactory,
+        const armnn::IBackendInternal::IMemoryManagerSharedPtr& memoryManager);
+
+//
 // Abs
 //
 
diff --git a/src/backends/cl/test/ClLayerTests.cpp b/src/backends/cl/test/ClLayerTests.cpp
index 294c77bf7f..cfec81a4c3 100644
--- a/src/backends/cl/test/ClLayerTests.cpp
+++ b/src/backends/cl/test/ClLayerTests.cpp
@@ -39,6 +39,9 @@ ARMNN_AUTO_TEST_CASE(ConstantLinearActivation, ConstantLinearActivationTest)
 ARMNN_AUTO_TEST_CASE(ReLu1Uint8, BoundedReLuUint8UpperAndLowerBoundTest)
 ARMNN_AUTO_TEST_CASE(ReLu6Uint8, BoundedReLuUint8UpperBoundOnlyTest)
 
+// Elu Activation
+ARMNN_AUTO_TEST_CASE(Elu, EluTest)
+
 ARMNN_AUTO_TEST_CASE(Logistic, SimpleSigmoidTest)
 ARMNN_AUTO_TEST_CASE(LogisticUint8, SimpleSigmoidUint8Test)
 
diff --git a/src/backends/neon/test/NeonLayerTests.cpp b/src/backends/neon/test/NeonLayerTests.cpp
index 1a9d7a9c50..18658a34a1 100644
--- a/src/backends/neon/test/NeonLayerTests.cpp
+++ b/src/backends/neon/test/NeonLayerTests.cpp
@@ -418,6 +418,9 @@ ARMNN_AUTO_TEST_CASE(ConstantLinearActivation, ConstantLinearActivationTest)
 ARMNN_AUTO_TEST_CASE(ReLu1Uint8, BoundedReLuUint8UpperAndLowerBoundTest)
 ARMNN_AUTO_TEST_CASE(ReLu6Uint8, BoundedReLuUint8UpperBoundOnlyTest)
 
+// Elu Activation
+ARMNN_AUTO_TEST_CASE(Elu, EluTest)
+
 // Sigmoid
 ARMNN_AUTO_TEST_CASE(SimpleSigmoid, SimpleSigmoidTest)
 ARMNN_AUTO_TEST_CASE(SimpleSigmoidUint8, SimpleSigmoidUint8Test)
diff --git a/src/backends/reference/RefLayerSupport.cpp b/src/backends/reference/RefLayerSupport.cpp
index 5cb36c4299..8f1f170c5c 100644
--- a/src/backends/reference/RefLayerSupport.cpp
+++ b/src/backends/reference/RefLayerSupport.cpp
@@ -108,6 +108,7 @@ bool RefLayerSupport::IsActivationSupported(const TensorInfo& input,
             {
                 case ActivationFunction::Abs:
                 case ActivationFunction::BoundedReLu:
+                case ActivationFunction::Elu:
                 case ActivationFunction::LeakyReLu:
                 case ActivationFunction::Linear:
                 case ActivationFunction::ReLu:
diff --git a/src/backends/reference/test/RefLayerTests.cpp b/src/backends/reference/test/RefLayerTests.cpp
index 99468e0006..d5c67ef6c7 100644
--- a/src/backends/reference/test/RefLayerTests.cpp
+++ b/src/backends/reference/test/RefLayerTests.cpp
@@ -462,6 +462,10 @@ ARMNN_AUTO_TEST_CASE(Tanh, TanhTest)
 ARMNN_AUTO_TEST_CASE(TanhUint8, TanhUint8Test)
 ARMNN_AUTO_TEST_CASE(TanhInt16, TanhInt16Test)
 
+// Elu Activation
+ARMNN_AUTO_TEST_CASE(Elu, EluTest)
+ARMNN_AUTO_TEST_CASE(EluUint8, EluUint8Test)
+ARMNN_AUTO_TEST_CASE(EluInt16, EluInt16Test)
 
 // Fully Connected
 ARMNN_AUTO_TEST_CASE(SimpleFullyConnected, FullyConnectedFloat32Test, false, false)
diff --git a/src/backends/reference/workloads/Activation.cpp b/src/backends/reference/workloads/Activation.cpp
index 814a0ddd13..82dd919de9 100644
--- a/src/backends/reference/workloads/Activation.cpp
+++ b/src/backends/reference/workloads/Activation.cpp
@@ -69,6 +69,11 @@ float Activation(float in,
             output = a * tanhf(b * in);
             break;
         }
+        case ActivationFunction::Elu:
+        {
+            output = (in >= 0) ? in : a * (expf(in) - 1);
+            break;
+        }
         default:
         {
             throw InvalidArgumentException("Unsupported activation function");