IVGCVSW-2510 Ref workload implementation for Gather operator

 * add implemenentation for GatherQueueDescriptor validate function
 * add FirstInputTypedWorkload to allow type check on the first input tensor only
 * add ref workload implemenentation for float and uint8
 * add Gather layer support in Ref
 * unit tests

Change-Id: I4578a3211f11d24aa29d15bcf7f45b0445bcd1ee

1 files changed, 64 insertions, 0 deletions

diff --git a/src/backends/reference/workloads/Gather.cpp b/src/backends/reference/workloads/Gather.cpp
new file mode 100644
index 0000000000..b195003e04
--- /dev/null
+++ b/src/backends/reference/workloads/Gather.cpp
@@ -0,0 +1,64 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "Gather.hpp"
+
+#include "RefWorkloadUtils.hpp"
+
+#include <backendsCommon/WorkloadData.hpp>
+
+namespace armnn
+{
+
+template <typename T>
+void Gather(const TensorInfo& paramsInfo,
+            const TensorInfo& indicesInfo,
+            const TensorInfo& outputInfo,
+            const T* params,
+            const int32_t* indices,
+            T* output)
+{
+    const TensorShape& paramsShape = paramsInfo.GetShape();
+
+    unsigned int paramsProduct = 1;
+    for (unsigned int i = 1; i < paramsInfo.GetNumDimensions(); ++i)
+    {
+        paramsProduct = paramsProduct * paramsShape[i];
+    }
+
+    unsigned int outIndex = 0;
+    for (unsigned int i = 0; i < indicesInfo.GetNumElements(); ++i)
+    {
+        unsigned int indx = boost::numeric_cast<unsigned int>(indices[i]);
+
+        BOOST_ASSERT(indices[i] >= 0 && indx < paramsShape[0]);
+
+        unsigned int startOffset = indx * paramsProduct;
+        unsigned int endOffset = startOffset + paramsProduct;
+        for (unsigned int j = startOffset; j < endOffset; ++j)
+        {
+            output[outIndex] = params[j];
+            ++outIndex;
+        }
+    }
+
+    BOOST_ASSERT(outIndex == outputInfo.GetNumElements());
+}
+
+template void Gather<float>(const TensorInfo& paramsInfo,
+                            const TensorInfo& indicesInfo,
+                            const TensorInfo& outputInfo,
+                            const float* params,
+                            const int32_t* indices,
+                            float* output);
+
+template void Gather<uint8_t>(const TensorInfo& paramsInfo,
+                              const TensorInfo& indicesInfo,
+                              const TensorInfo& outputInfo,
+                              const uint8_t* params,
+                              const int32_t* indices,
+                              uint8_t* output);
+
+} //namespace armnn