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

3 files changed, 10 insertions, 0 deletions

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");