Suspicious `for`-`while`-loops in ParzenWindowMutualInformationImageToImageMetric

[N-Dekker]

The following looks suspicious:

        for (unsigned int i = 0; i < nzji.size(); ++i)
        {
          while (imjacit != imageJacobian.end())
          {
            *imjacit *= *jacprecit;
            ++imjacit;
            ++jacprecit;
          }
        }

When the while loop is completely processed for the first time, imjacit will be at imageJacobian.end(), so the next for-loop iterations (for i > 0) won't do much anymore.

This very same code is encountered twice in itkParzenWindowMutualInformationImageToImageMetric.hxx, probably copy-and-pasted:

elastix/Components/Metrics/AdvancedMattesMutualInformation/itkParzenWindowMutualInformationImageToImageMetric.hxx

Lines 345 to 353 in 8ae83b8

	for (unsigned int i = 0; i < nzji.size(); ++i)
	{
	while (imjacit != imageJacobian.end())
	{
	*imjacit *= *jacprecit;
	++imjacit;
	++jacprecit;
	}
	}

elastix/Components/Metrics/AdvancedMattesMutualInformation/itkParzenWindowMutualInformationImageToImageMetric.hxx

Lines 490 to 498 in 8ae83b8

	for (unsigned int i = 0; i < nzji.size(); ++i)
	{
	while (imjacit != imageJacobian.end())
	{
	*imjacit *= *jacprecit;
	++imjacit;
	++jacprecit;
	}
	}

The for-while loop appears introduced by commit 1767cd3, May 22, 2009, at

elastix/src/Components/Metrics/AdvancedMattesMutualInformation/itkParzenWindowMutualInformationImageToImageMetric.hxx

Lines 342 to 348 in 1767cd3

	for ( unsigned int i = 0; i < this->m_NonZeroJacobianIndices.size(); ++i )
	while ( imjacit != imageJacobian.end() )
	{
	(*imjacit) *= (*jacprecit);
	++imjacit;
	++jacprecit;
	}