Function AssignBackends

src/armnn/Network.cpp:1212–1293

}

OptimizationResult AssignBackends(OptimizedNetworkImpl* optNetObjPtr,
                                  BackendSettings& backendSettings,
                                  Graph::Iterator& firstLayer,
                                  Graph::Iterator& lastLayer,
                                  Optional<std::vector<std::string>&> errMessages)
{
    ARMNN_SCOPED_PROFILING_EVENT(Compute::Undefined, "Optimizer_AssignBackends");
    OptimizationResult result;

    bool restart = false;
    BackendIdVector availablePreferredBackends;
    for (auto it = firstLayer; it != lastLayer; it = (restart ? firstLayer : ++it))
    {
        if (it == firstLayer)
        {
            availablePreferredBackends = backendSettings.GetAvailablePreferredBackends();
            if (availablePreferredBackends.empty())
                {
                        ReportError("No preferred backends are available", errMessages);
                        result.m_Error = true;
                        return result;
                }
        }
        // In the case where we've set restart it must be reset before we continue looking at backends.
        if (restart)
        {
            restart = false;
        }
        AssignBackendsIConnectable(optNetObjPtr,
                                   *it,
                                   errMessages,
                                   result,
                                   backendSettings,
                                   availablePreferredBackends,
                                   restart);
    }

    for (auto it = firstLayer; it != lastLayer; ++it)
    {
        auto layer = PolymorphicDowncast<Layer*>(*it);
        std::vector<DataType> inOutDataType = GetLayerInOutDatatype(layer);

        // In AttemptBackendAssignment() we check:
        //     - if input/output datatypes of the layer are float16
        //     - if the layer is supported with these datatypes
        // If the layer is not supported (failing on ARM_COMPUTE_RETURN_ERROR_ON_CPU_F16_UNSUPPORTED() in clframework),
        // we attempt to insert convertion layers either side of the new fp32 layer.
        bool isFloat16 = false;
        for (auto type : inOutDataType)
        {
            if (type == DataType::Float16)
            {
                isFloat16 = true;
                break;
            }
        }

        if (layer->GetBackendId() == "Unknown" || isFloat16)