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/*=========================================================================
*
* Copyright Insight Software Consortium
*
* 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
*
* http://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.
*
*=========================================================================*/
#include "itkMahalanobisDistanceMetric.h"
int itkMahalanobisDistanceMetricTest(int, char* [] )
{
const unsigned int MeasurementVectorSize = 3;
typedef itk::Array< float > MeasurementVectorType;
typedef itk::Statistics::MahalanobisDistanceMetric< MeasurementVectorType > DistanceMetricType;
DistanceMetricType::Pointer distance = DistanceMetricType::New();
std::cout << distance->GetNameOfClass() << std::endl;
distance->Print(std::cout);
distance->SetMeasurementVectorSize( MeasurementVectorSize );
if( distance->GetMeasurementVectorSize() != MeasurementVectorSize )
{
std::cerr << "GetMeasurementVectorSize() Failed !" << std::endl;
return EXIT_FAILURE;
}
//Test if the distance computed is correct
DistanceMetricType::OriginType origin;
::itk::NumericTraits<DistanceMetricType::OriginType>::SetLength( origin, 3);
origin[0] = 1.5;
origin[1] = 2.3;
origin[2] = 1.0;
distance->SetMean( origin );
//double value comparison tolerance
const double tolerance = 0.001;
if( std::fabs(distance->GetMean()[0] - origin[0]) > tolerance ||
std::fabs(distance->GetMean()[1] - origin[1]) > tolerance ||
std::fabs(distance->GetMean()[2] - origin[2]) > tolerance )
{
std::cerr << " Set/Get Origin error " << std::endl;
return EXIT_FAILURE;
}
MeasurementVectorType measurement;
::itk::NumericTraits<MeasurementVectorType>::SetLength( measurement, 3);
measurement[0] = 2.5;
measurement[1] = 3.3;
measurement[2] = 4.0;
double trueValue = 3.31662;
double distanceComputed = distance->Evaluate( measurement );
if( std::fabs( distanceComputed - trueValue) > tolerance )
{
std::cerr << "Distance computed not correct: " << "truevalue= " << trueValue
<< "ComputedValue=" << distanceComputed << std::endl;
return EXIT_FAILURE;
}
//Test if we get the same result with identity covariance matrix set
DistanceMetricType::CovarianceMatrixType covarianceMatrix;
covarianceMatrix.set_size( MeasurementVectorSize, MeasurementVectorSize );
covarianceMatrix.set_identity();
distance->SetCovariance( covarianceMatrix );
if( distance->GetCovariance() != covarianceMatrix )
{
std::cerr << "Get/SetCovariance method error" << std::endl;
return EXIT_FAILURE;
}
double epsilon = 1e-200;
double doubleMax = 1e+25;
distance->SetEpsilon( epsilon );
distance->SetDoubleMax( doubleMax );
//Test Set/Get Epsilon method
if( std::fabs( distance->GetEpsilon() - epsilon ) > tolerance )
{
std::cerr << "Get/SetEpsilon method error" << std::endl;
return EXIT_FAILURE;
}
//Test Set/Get DoubleMax method
if( std::fabs( distance->GetDoubleMax() - doubleMax ) > tolerance )
{
std::cerr << "Get/SetDoubleMax method error" << std::endl;
return EXIT_FAILURE;
}
if( std::fabs( distanceComputed - trueValue) > tolerance )
{
std::cerr << "Distance computed not correct: " << "truevalue= " << trueValue
<< "ComputedValue=" << distanceComputed << std::endl;
return EXIT_FAILURE;
}
//Test if an exception is thrown if a covariance matrix is set with different
//size
DistanceMetricType::CovarianceMatrixType covarianceMatrix2;
DistanceMetricType::MeasurementVectorSizeType measurementSize2 = 4;
covarianceMatrix2.set_size( measurementSize2, measurementSize2 );
try
{
distance->SetCovariance( covarianceMatrix2 );
std::cerr << "Exception should have been thrown: " << std::endl;
return EXIT_FAILURE;
}
catch( itk::ExceptionObject & excpt )
{
std::cerr << "Exception caught: " << excpt << std::endl;
}
//Set a covariance matrix and check if the computed inverse matrix is
//correct
//
DistanceMetricType::CovarianceMatrixType covarianceMatrix3;
covarianceMatrix3.set_size( MeasurementVectorSize, MeasurementVectorSize );
covarianceMatrix3[0][0] = 2.0;
covarianceMatrix3[0][1] = 1.4;
covarianceMatrix3[0][2] = 5.0;
covarianceMatrix3[1][0] = 3.0;
covarianceMatrix3[1][1] = 2.0;
covarianceMatrix3[1][2] = 5.4;
covarianceMatrix3[2][0] = 3.2;
covarianceMatrix3[2][1] = 1.4;
covarianceMatrix3[2][2] = 7.4;
distance->SetCovariance( covarianceMatrix3 );
//establish the true inverse covariance matrix
DistanceMetricType::CovarianceMatrixType trueInverseCovarianceMatrix;
trueInverseCovarianceMatrix.set_size( MeasurementVectorSize, MeasurementVectorSize );
trueInverseCovarianceMatrix[0][0] = -2.124;
trueInverseCovarianceMatrix[0][1] = 0.986;
trueInverseCovarianceMatrix[0][2] = 0.716;
trueInverseCovarianceMatrix[1][0] = 1.444;
trueInverseCovarianceMatrix[1][1] = 0.352;
trueInverseCovarianceMatrix[1][2] = -1.232;
trueInverseCovarianceMatrix[2][0] = 0.646;
trueInverseCovarianceMatrix[2][1] = -0.493;
trueInverseCovarianceMatrix[2][2] = 0.059;
// Get the computed inverse covariance matrix
DistanceMetricType::CovarianceMatrixType computedInverseCovarianceMatrix;
computedInverseCovarianceMatrix = distance->GetInverseCovariance();
if( std::fabs( trueInverseCovarianceMatrix[0][0] - computedInverseCovarianceMatrix[0][0] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[0][1] - computedInverseCovarianceMatrix[0][1] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[0][2] - computedInverseCovarianceMatrix[0][2] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[1][0] - computedInverseCovarianceMatrix[1][0] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[1][1] - computedInverseCovarianceMatrix[1][1] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[1][2] - computedInverseCovarianceMatrix[1][2] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[2][0] - computedInverseCovarianceMatrix[2][0] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[2][1] - computedInverseCovarianceMatrix[2][1] ) > tolerance ||
std::fabs( trueInverseCovarianceMatrix[2][2] - computedInverseCovarianceMatrix[2][2] ) > tolerance )
{
std::cerr << "Inverse computation error" << std::endl;
return EXIT_FAILURE;
}
//Run the distance metric with a single component measurement vector size
DistanceMetricType::MeasurementVectorSizeType
singleComponentMeasurementVectorSize = 1;
distance->SetMeasurementVectorSize( singleComponentMeasurementVectorSize );
::itk::NumericTraits<DistanceMetricType::OriginType>::SetLength( origin, 1);
origin[0] = 1.5;
distance->SetMean( origin );
if( std::fabs(distance->GetMean()[0] - origin[0]) > tolerance )
{
std::cerr << " Set/Get Origin error " << std::endl;
return EXIT_FAILURE;
}
covarianceMatrix.set_size( singleComponentMeasurementVectorSize,
singleComponentMeasurementVectorSize );
covarianceMatrix[0][0] = 1.0;
distance->SetCovariance( covarianceMatrix );
MeasurementVectorType measurementSingleComponent;
::itk::NumericTraits<MeasurementVectorType>::SetLength( measurementSingleComponent, 1);
measurementSingleComponent[0] = 2.5;
trueValue = 1.0;
distanceComputed = distance->Evaluate( measurementSingleComponent );
if( std::fabs( distanceComputed - trueValue) > tolerance )
{
std::cerr << "Distance computed not correct: " << "truevalue= " << trueValue
<< "ComputedValue=" << distanceComputed << std::endl;
return EXIT_FAILURE;
}
//Compute distance between two measurement vectors
MeasurementVectorType measurementSingleComponent2;
::itk::NumericTraits<MeasurementVectorType>::SetLength( measurementSingleComponent2, 1);
measurementSingleComponent2[0] = 1.5;
trueValue = 1.0;
distanceComputed = distance->Evaluate( measurementSingleComponent, measurementSingleComponent2 );
if( std::fabs( distanceComputed - trueValue) > tolerance )
{
std::cerr << "Distance computed not correct: " << "truevalue= " << trueValue
<< "ComputedValue=" << distanceComputed << std::endl;
return EXIT_FAILURE;
}
//Attempt to compute distance between two unequal size measurement vectors
MeasurementVectorType measurementSingleComponent3;
::itk::NumericTraits<MeasurementVectorType>::SetLength( measurementSingleComponent3, 2);
measurementSingleComponent3[0] = 1.5;
measurementSingleComponent3[1] = 2.5;
distance->Evaluate( measurementSingleComponent, measurementSingleComponent2 );
try
{
distance->Evaluate( measurementSingleComponent, measurementSingleComponent3 );
std::cerr << "Attempting to compute distance between unequal size measurement vectors"
<< "Exception should have been thrown: " << std::endl;
return EXIT_FAILURE;
}
catch( itk::ExceptionObject & excpt )
{
std::cerr << "Exception caught: " << excpt << std::endl;
}
return EXIT_SUCCESS;
}
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