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Original file line number Diff line number Diff line change
Expand Up @@ -77,15 +77,16 @@ ScaleLogarithmicTransform<TParametersValueType, VDimension>::ComputeJacobianWith
const InputPointType & p,
JacobianType & jacobian) const
{
const ScaleType & scales = this->GetScale();
const ScaleType & scales = this->GetScale();
const InputPointType & center = this->GetCenter();

jacobian.SetSize(SpaceDimension, this->GetNumberOfLocalParameters());
jacobian.Fill(0);
for (unsigned int dim = 0; dim < SpaceDimension; ++dim)
{
// the derivative with respect to Log(scale) = scale * derivative with
// respect to scale.
jacobian(dim, dim) = scales[dim] * p[dim];
jacobian(dim, dim) = scales[dim] * (p[dim] - center[dim]);
}
}

Expand Down
48 changes: 48 additions & 0 deletions Modules/Core/Transform/test/itkScaleLogarithmicTransformTest.cxx
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
*
*=========================================================================*/

#include <cmath>
#include <iostream>

#include "itkScaleLogarithmicTransform.h"
Expand Down Expand Up @@ -266,6 +267,53 @@ itkScaleLogarithmicTransformTest(int, char *[])
}


// Exercise the Jacobian about a non-zero center
{
auto centeredTransform = TransformType::New();

TransformType::InputPointType center;
center[0] = 5;
center[1] = 6;
center[2] = 7;
centeredTransform->SetCenter(center);

TransformType::ParametersType parameters = centeredTransform->GetParameters();
parameters[0] = std::log(2.0);
parameters[1] = std::log(3.0);
parameters[2] = std::log(4.0);
centeredTransform->SetParameters(parameters);

constexpr TransformType::InputPointType::ValueType pInit[3]{ 10, 10, 10 };
const TransformType::InputPointType p = pInit;

TransformType::JacobianType jacobian;
centeredTransform->ComputeJacobianWithRespectToParameters(p, jacobian);

const TransformType::ScaleType & scales = centeredTransform->GetScale();

testStatus = true;
for (unsigned int i = 0; i < N; ++i)
{
// d/dLog(scale[i]) of scale[i] * (p[i] - center[i]) + center[i]
const double expected = scales[i] * (p[i] - center[i]);
if (itk::Math::Absolute(jacobian(i, i) - expected) > epsilon)
{
testStatus = false;
break;
}
}
if (!testStatus)
{
std::cerr << "Error in ComputeJacobianWithRespectToParameters()." << std::endl;
std::cerr << "The center of the transformation was ignored." << std::endl;
std::cerr << "Jacobian: " << jacobian << std::endl;
return EXIT_FAILURE;
}

std::cout << "Successful ComputeJacobianWithRespectToParameters() " << std::endl;
}


std::cout << "Test finished" << std::endl;
return EXIT_SUCCESS;
}
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