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/*=========================================================================
*
* Copyright NumFOCUS
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#ifndef itkMeanSampleFilter_hxx
#define itkMeanSampleFilter_hxx
#include <vector>
#include "itkCompensatedSummation.h"
#include "itkMeasurementVectorTraits.h"
namespace itk
{
namespace Statistics
{
template <typename TSample>
MeanSampleFilter<TSample>::MeanSampleFilter()
{
this->ProcessObject::SetNumberOfRequiredInputs(1);
this->ProcessObject::SetNumberOfRequiredOutputs(1);
this->ProcessObject::SetNthOutput(0, this->MakeOutput(0));
}
template <typename TSample>
void
MeanSampleFilter<TSample>::SetInput(const SampleType * sample)
{
this->ProcessObject::SetNthInput(0, const_cast<SampleType *>(sample));
}
template <typename TSample>
const TSample *
MeanSampleFilter<TSample>::GetInput() const
{
return itkDynamicCastInDebugMode<const SampleType *>(this->GetPrimaryInput());
}
template <typename TSample>
auto
MeanSampleFilter<TSample>::MakeOutput(DataObjectPointerArraySizeType itkNotUsed(idx)) -> DataObjectPointer
{
MeasurementVectorRealType mean;
(void)mean; // for complainty pants : valgrind
NumericTraits<MeasurementVectorRealType>::SetLength(mean, this->GetMeasurementVectorSize());
// NumericTraits::SetLength also initializes array to zero
auto decoratedMean = MeasurementVectorDecoratedType::New();
decoratedMean->Set(mean);
return decoratedMean.GetPointer();
}
template <typename TSample>
auto
MeanSampleFilter<TSample>::GetOutput() const -> const MeasurementVectorDecoratedType *
{
return itkDynamicCastInDebugMode<const MeasurementVectorDecoratedType *>(this->ProcessObject::GetOutput(0));
}
template <typename TSample>
auto
MeanSampleFilter<TSample>::GetMean() const -> const MeasurementVectorRealType
{
const MeasurementVectorDecoratedType * decorator = this->GetOutput();
return decorator->Get();
}
template <typename TSample>
auto
MeanSampleFilter<TSample>::GetMeasurementVectorSize() const -> MeasurementVectorSizeType
{
const SampleType * input = this->GetInput();
if (input)
{
return input->GetMeasurementVectorSize();
}
// Test if the Vector type knows its length
MeasurementVectorSizeType measurementVectorSize = NumericTraits<MeasurementVectorType>::GetLength({});
if (measurementVectorSize)
{
return measurementVectorSize;
}
measurementVectorSize = 1; // Otherwise set it to an innocuous value
return measurementVectorSize;
}
template <typename TSample>
void
MeanSampleFilter<TSample>::GenerateData()
{
// set up input / output
const SampleType * input = this->GetInput();
const MeasurementVectorSizeType measurementVectorSize = input->GetMeasurementVectorSize();
auto * decoratedOutput =
itkDynamicCastInDebugMode<MeasurementVectorDecoratedType *>(this->ProcessObject::GetOutput(0));
MeasurementVectorRealType output = decoratedOutput->Get();
NumericTraits<MeasurementVectorRealType>::SetLength(output, this->GetMeasurementVectorSize());
// algorithm start
using MeasurementRealAccumulateType = CompensatedSummation<MeasurementRealType>;
std::vector<MeasurementRealAccumulateType> sum(measurementVectorSize);
using TotalFrequencyType = typename SampleType::TotalAbsoluteFrequencyType;
TotalFrequencyType totalFrequency{};
typename SampleType::ConstIterator iter = input->Begin();
const typename SampleType::ConstIterator end = input->End();
for (; iter != end; ++iter)
{
const MeasurementVectorType & measurement = iter.GetMeasurementVector();
const typename SampleType::AbsoluteFrequencyType frequency = iter.GetFrequency();
totalFrequency += frequency;
for (unsigned int dim = 0; dim < measurementVectorSize; ++dim)
{
const auto component = static_cast<MeasurementRealType>(measurement[dim]);
sum[dim] += (component * static_cast<MeasurementRealType>(frequency));
}
}
// compute the mean if the total frequency is different from zero
if (totalFrequency > itk::Math::eps)
{
for (unsigned int dim = 0; dim < measurementVectorSize; ++dim)
{
output[dim] = (sum[dim].GetSum() / static_cast<MeasurementRealType>(totalFrequency));
}
}
else
{
itkExceptionMacro("Total frequency was too close to zero: " << totalFrequency);
}
decoratedOutput->Set(output);
}
} // end of namespace Statistics
} // end of namespace itk
#endif
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