IVGCVSW-2512 Add Gather operator parser to TfParser

 * Add ParseGather to TFParser
 * Add Unit tests for Gather Operator

!armnn:562

Change-Id: Idff45c2d3d8d683aa9eb2c4a63123c8d6054609e

1 files changed, 37 insertions, 0 deletions

diff --git a/src/armnnTfParser/TfParser.cpp b/src/armnnTfParser/TfParser.cpp
index 15a91d5275..43b0d86000 100755
--- a/src/armnnTfParser/TfParser.cpp
+++ b/src/armnnTfParser/TfParser.cpp
@@ -332,6 +332,7 @@ const std::map<std::string, TfParser::OperationParsingFunction> TfParser::ms_Ope
     { "DepthwiseConv2dNative", &TfParser::ParseDepthwiseConv2D },
     { "ExpandDims",            &TfParser::ParseExpandDims },
     { "FusedBatchNorm",        &TfParser::ParseFusedBatchNorm },
+    { "Gather",                &TfParser::ParseGather},
     { "Greater",               &TfParser::ParseGreater},
     { "ConcatV2",              &TfParser::ParseConcat },
     { "LRN",                   &TfParser::ParseLrn },
@@ -1766,6 +1767,42 @@ ParsedTfOperationPtr TfParser::ProcessElementwiseLayer(
     return std::make_unique<SingleLayerParsedTfOperation>(this, nodeDef, layer);
 }
 
+ParsedTfOperationPtr TfParser::ParseGather(const tensorflow::NodeDef& nodeDef,
+                                           const tensorflow::GraphDef& graphDef)
+{
+    std::vector<OutputOfParsedTfOperation> inputs = GetInputParsedTfOperationsChecked(nodeDef, 2);
+    IOutputSlot& params = inputs[0].m_IndexedValue->ResolveArmnnOutputSlot(inputs[0].m_Index);
+    IOutputSlot& indices = inputs[1].m_IndexedValue->ResolveArmnnOutputSlot(inputs[1].m_Index);
+
+    // Infer shape of output tensor
+    unsigned int paramsDim = params.GetTensorInfo().GetNumDimensions();
+    unsigned int indicesDim = indices.GetTensorInfo().GetNumDimensions();
+    unsigned int outputDim = paramsDim - 1 + indicesDim;
+
+    std::vector<unsigned int> dimSizes;
+
+    for (unsigned int i = 0; i < indicesDim; ++i)
+    {
+        dimSizes.push_back(indices.GetTensorInfo().GetShape()[i]);
+    }
+    for (unsigned int i = 1; i < paramsDim; ++i)
+    {
+        dimSizes.push_back(params.GetTensorInfo().GetShape()[i]);
+    }
+
+    const TensorShape& inferredShape = TensorShape(outputDim, dimSizes.data());
+
+    const TensorInfo inferredOutputInfo(inferredShape, params.GetTensorInfo().GetDataType());
+
+    IConnectableLayer* const layer = m_Network->AddGatherLayer(nodeDef.name().c_str());
+    layer->GetOutputSlot(0).SetTensorInfo(inferredOutputInfo);
+
+    params.Connect(layer->GetInputSlot(0));
+    indices.Connect(layer->GetInputSlot(1));
+
+    return std::make_unique<SingleLayerParsedTfOperation>(this, nodeDef, layer);
+}
+
 ParsedTfOperationPtr TfParser::ParseGreater(const tensorflow::NodeDef& nodeDef,
                                             const tensorflow::GraphDef& graphDef)
 {