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 # Class simulation\_framework::evaluator::GtBaseEvaluator

 Last update: 22.04.2026 

![](https://img.shields.io/badge/language-C%2B%2B-blue "C++")![](https://img.shields.io/badge/-public-brightgreen "public")

**Definition**: `autonomy/evaluator/gt_base_evaluator/gt_base_evaluator.h` (line 133)

This is the implementation of IEvaluator interface and provides users ability to evaluate KPIs that are added by themselves. This class controls all KPIs centrally and fill/reset the KpiMessage accordingly based on each KPI's calculation result.

To join the simulation, the evaluator must be injected into an Activity and required KPIs need to be added using [AddKpi(std::unique\_ptr<core::kpi::IKpi<osi3::GroundTruth>> kpi)](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a7d9970bad7943a552c385b01785fb66f).

Example of creating one customized KpiEvaluatorActivity containing 2 KPIs and publish the KpiMessage into KpiLoggerTopic to have the KPI results in output json

```cpp

class MyFirstKpi : public core::kpi::IKpi<osi3::GroundTruth>
{
  public:
    MyFirstKpi(const std::string& kpi_name): kpi_name_(kpi_name) {}
    void Init() override {}
    void Reset() override {}
    kpi::KpiContent CalculateKpi(const osi3::GroundTruth& ground_truth) override
    {
        kpi::KpiContent kpi;
        return kpi;
    }
    kpi::Type GetKpiType() const override { return kpi::Type::kScalar; }
};
class MySecondKpi : public core:kpi::IKpi<osi3::GroundTruth> { 

class MyKpiEvaluatorActivity : public BaseActivity
{
  public:
    MyKpiEvaluatorActivity(const std::string& name,
                           const Topics& topics,
                           evaluator::std::unique_ptr<kpi::IKpiMessageConverter> kpi_message_converter,
                           std::unique_ptr<core::IEvaluator<osi3::GroundTruth>> evaluator)
        : BaseActivity(name, topics),
          kpi_message_converter_(std::move(kpi_message_converter)),
          evaluator_(std::move(evaluator))
    {
        evaluator_->Init();
    }

    ~MyKpiEvaluatorActivity() = default;

    void AddPublisherAndSubscriber() override
    {
        AddSubscriber<core::Topic<rtidds::GenericBytesMessage>>(
            "SensorViewTopic", [&](const rtidds::GenericBytesMessage& sv_bytes_msg) {
                if (!osi_proto_sv_.ParseFromArray(sv_bytes_msg.bytes_array.data(), sv_bytes_msg.size))
                {
                    throw std::runtime_error(
                        "[MyKpiEvaluatorActivity]: Error parsing "
                        "osi proto msg from bytes array!");
                }
            });

        AddPublisher<core::Topic<rtidds::KpiMessage>>("KpiLoggerTopic", [&]() {
            const auto dds_kpi_message = kpi_message_converter_->ConvertToDds(kpi_message_);
            return dds_kpi_message;
        });
    }

    void ExecuteStep() override
    {
        evaluator_->SetInput(osi_proto_sv_.global_ground_truth());
        evaluator_->Evaluate();
        kpi_message_ = evaluator_->GetKpiMessage();
    }

  private:
    evaluator::std::unique_ptr<kpi::IKpiMessageConverter> kpi_message_converter_;
    std::unique_ptr<core::IEvaluator<osi3::GroundTruth>>evaluator_;
    core::kpi::KpiMessage kpi_message_;
    osi3::SensorView osi_proto_sv_{};
};


 auto my_first_kpi = std::make_unique<MyFirstKpi>("kpi_1");
 auto my_second_kpi = std::make_unique<MySecondKpi>("kpi_2");

 auto evaluator = std::make_unique<simulation_framework::evaluator::BaseEvaluator>();
 evaluator->AddKpi(std::move(my_first_kpi));
 evaluator->AddKpi(std::move(my_second_kpi));

 auto kpi_message_converter = std::make_unique<core::kpi::KpiMessageConverter>();

 auto my_kpi_evaluator_activity = std::make_unique<MyKpiEvaluatorActivity>(
                                                 "MyKpiEvaluatorActivity",
Topics{autonomy::topic_registry::GetExistingTopicById("SensorViewTopic"),
autonomy::topic_registry::GetExistingTopicById("KpiLoggerTopic")},
                                                 std::move(kpi_message_converter),
                                                 std::move(evaluator));

```

**Inherits from**:

- [simulation\_framework::core::IEvaluator&lt; osi3::GroundTruth &gt;](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator)

## Members

- [AddKpi](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a7d9970bad7943a552c385b01785fb66f)
- [AddKpi](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator_1a382b22c39881af2b0397df0caee82063)
- [Evaluate](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a09b8959aaaacce2b842abfd304b63674)
- [GetKpiMessage](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a2e37677f4b8884d78f028589c6adac48)
- [GtBaseEvaluator](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1aa962203ea42d414d0584ada57d955203)
- [Init](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a930cb234264aa995b30eab8c537a15ad)
- [Reset](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1acacfb885fab2f83b114e870fa9433f3d)
- [SetInput](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1adc68080d44c2f5a294dbb511fe7d1c77)
- [~GtBaseEvaluator](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1af8902ec9d60bf7a6fbb49f0d18d9c902)
- [~IEvaluator](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator_1a605a97c7c7aef7588ff1ce0957d97f79)

## Public functions

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1aa962203ea42d414d0584ada57d955203"></a>

### Function GtBaseEvaluator

![](https://img.shields.io/badge/-public-brightgreen "public")

```cpp
simulation_framework::evaluator::GtBaseEvaluator::GtBaseEvaluator()

```

**Return type**:

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1af8902ec9d60bf7a6fbb49f0d18d9c902"></a>

### Function ~GtBaseEvaluator

![](https://img.shields.io/badge/-public-brightgreen "public")

```cpp
virtual simulation_framework::evaluator::GtBaseEvaluator::~GtBaseEvaluator()=default

```

**Return type**:

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a930cb234264aa995b30eab8c537a15ad"></a>

### Function Init

![](https://img.shields.io/badge/-public-brightgreen "public")

```cpp
void simulation_framework::evaluator::GtBaseEvaluator::Init()

```

Initial all KPIs (call all kpi-&gt;[Init()](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a930cb234264aa995b30eab8c537a15ad);) which are added in this evaluator

**Return type**: void

**Reimplements**: [Init](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator_1ac62458dfff2bf4a0287bc48335bec4ff)

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1acacfb885fab2f83b114e870fa9433f3d"></a>

### Function Reset

![](https://img.shields.io/badge/-public-brightgreen "public")

```cpp
void simulation_framework::evaluator::GtBaseEvaluator::Reset()

```

Clear KpiMessage and reset all KPIs (call all kpi-&gt;[Reset()](classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator.md#classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1acacfb885fab2f83b114e870fa9433f3d);) which are added in this evaluator

**Return type**: void

**Reimplements**: [Reset](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator_1a4f2140b6e5dc9289d084c601c1f28cf2)

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a09b8959aaaacce2b842abfd304b63674"></a>

### Function Evaluate

![](https://img.shields.io/badge/-public-brightgreen "public")

```cpp
void simulation_framework::evaluator::GtBaseEvaluator::Evaluate()

```

Calculate all KPIs (call all kpi-&gt;CalculateKpi(gt);) which are added in this evaluator and fill the KpiMessage

**Return type**: void

**Reimplements**: [Evaluate](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator_1a251fb9feee11d29b6c4bd5161a7b7089)

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a7d9970bad7943a552c385b01785fb66f"></a>

### Function AddKpi

![](https://img.shields.io/badge/-public-brightgreen "public")

```cpp
void simulation_framework::evaluator::GtBaseEvaluator::AddKpi(std::unique_ptr< core::kpi::IKpi< osi3::GroundTruth > > kpi) override

```

Add one KPI into this evaluator

**Parameters**:

- **kpi**: The iKpi interface

**Parameters**:

- std::unique\_ptr&lt; [core::kpi::IKpi](classsimulation__framework_1_1core_1_1kpi_1_1IKpi.md#classsimulation__framework_1_1core_1_1kpi_1_1IKpi)&lt; osi3::GroundTruth &gt; &gt; **kpi**

**Return type**: void

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1a2e37677f4b8884d78f028589c6adac48"></a>

### Function GetKpiMessage

![](https://img.shields.io/badge/-public-brightgreen "public")![](https://img.shields.io/badge/-const-lightblue "const")

```cpp
core::kpi::KpiMessage simulation_framework::evaluator::GtBaseEvaluator::GetKpiMessage() const

```

Get the filled KPI messages based on calculation of all KPIs

**Returns**:

A kpi::KpiMessage object, the vector of KpiContent represents of all added KPIs into this evaluator

**Return type**: core::kpi::KpiMessage

**Reimplements**: [GetKpiMessage](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator_1a81ab03795b81308e647d4f7022a64d4a)

<a id="classsimulation__framework_1_1evaluator_1_1GtBaseEvaluator_1adc68080d44c2f5a294dbb511fe7d1c77"></a>

### Function SetInput

![](https://img.shields.io/badge/-public-brightgreen "public")

```cpp
void simulation_framework::evaluator::GtBaseEvaluator::SetInput(const osi3::GroundTruth &ground_truth)

```

Set GroundTruth message for KPI calculations

**Parameters**:

- **ground\_truth**: The osi groundtruth type in protobuf

**Parameters**:

- const osi3::GroundTruth &amp; **ground\_truth**

**Return type**: void

**Reimplements**: [SetInput](classsimulation__framework_1_1core_1_1IEvaluator.md#classsimulation__framework_1_1core_1_1IEvaluator_1a17db67a251425e3ecc47d45c03a1b056)