IVGCVSW-7752 DTS: Fix QuantizePerChannel tests

* Added validation for scale on all Quantized types
* Added Encoder for Per Axis UINT16 Symmetrical Quantized type
* Added error for Per Axis Asymmetrical Quantized type not supported

Signed-off-by: John Mcloughlin <john.mcloughlin@arm.com>
Change-Id: I433519ccacd71219a92bde2b81955d6abf9219c5

2 files changed, 47 insertions, 6 deletions

diff --git a/src/backends/reference/workloads/BaseIterator.hpp b/src/backends/reference/workloads/BaseIterator.hpp
index 2d27951b73..1665c1ff46 100644
--- a/src/backends/reference/workloads/BaseIterator.hpp
+++ b/src/backends/reference/workloads/BaseIterator.hpp
@@ -1,5 +1,5 @@
 //
-// Copyright © 2017 Arm Ltd. All rights reserved.
+// Copyright © 2017-2023 Arm Ltd and Contributors. All rights reserved.
 // SPDX-License-Identifier: MIT
 //
 
@@ -896,4 +896,31 @@ private:
     std::vector<float> m_Scales;
 };
 
+class QSymm16PerAxisEncoder : public PerAxisIterator<int16_t, Encoder<float>>
+{
+public:
+    QSymm16PerAxisEncoder(int16_t* data, const std::vector<float>& scale,
+                          unsigned int axisFactor, unsigned int axisDimensionality)
+            : PerAxisIterator(data, axisFactor, axisDimensionality), m_Scale(scale) {}
+
+    void Set(float right)
+    {
+        *m_Iterator = armnn::Quantize<int16_t>(right, m_Scale[m_AxisIndex], 0);
+    }
+
+    float Get() const
+    {
+        return armnn::Dequantize(*m_Iterator, m_Scale[m_AxisIndex], 0);
+    }
+
+    // Get scale of the current value
+    float GetScale() const
+    {
+        return m_Scale[m_AxisIndex];
+    }
+
+private:
+    std::vector<float> m_Scale;
+};
+
 } // namespace armnn
diff --git a/src/backends/reference/workloads/Encoders.hpp b/src/backends/reference/workloads/Encoders.hpp
index d6d611494d..8a702377b2 100644
--- a/src/backends/reference/workloads/Encoders.hpp
+++ b/src/backends/reference/workloads/Encoders.hpp
@@ -1,5 +1,5 @@
 //
-// Copyright © 2017 Arm Ltd. All rights reserved.
+// Copyright © 2017-2023 Arm Ltd and Contributors. All rights reserved.
 // SPDX-License-Identifier: MIT
 //
 
@@ -56,10 +56,24 @@ inline std::unique_ptr<Encoder<float>> MakeEncoder(const TensorInfo& info, void*
         }
         case armnn::DataType::QSymmS16:
         {
-            return std::make_unique<QSymm16Encoder>(
-                static_cast<int16_t*>(data),
-                info.GetQuantizationScale(),
-                info.GetQuantizationOffset());
+            if (info.HasPerAxisQuantization())
+            {
+                unsigned int axis = info.GetQuantizationDim().value();
+                auto axisDimensionality = info.GetShape()[axis];
+                std::pair<unsigned int, std::vector<float>> params = armnnUtils::GetPerAxisParams(info);
+                return std::make_unique<QSymm16PerAxisEncoder>(
+                        static_cast<int16_t*>(data),
+                        params.second,
+                        params.first,
+                        axisDimensionality);
+            }
+            else
+            {
+                return std::make_unique<QSymm16Encoder>(
+                        static_cast<int16_t *>(data),
+                        info.GetQuantizationScale(),
+                        info.GetQuantizationOffset());
+            }
         }
         case armnn::DataType::Signed32:
         {