[Insight-developers] Problem with ITK 3.20 itkQuadEdgeMeshDiscretePrincipalCurvaturesEstimator.h

[Alexandre GOUAILLARD]

i luis,

arnaud went ahead and fixed the bug directly in v4, so I ll let him
provide the patch to you.

in the meantime, I just wanted to clarify the process (those questions
should be answered by the ISC board I guess):

- are we going to have any other release of itk 3.x ?
- What items should be backported (I suppose bug fixes are, not enhancement)
- what is the process for backporting items to itk 3.x
   - untill itk v4 is out?
   - later on ?
- how long do we plan to support 3.x for backports ?

I guess we will have to face the sacro-saint question ...
do we commit in branches ... if yes, who does, when and how?

regards.

alex.


On Wed, Sep 15, 2010 at 11:08 PM, Luis Ibanez <luis.ibanez at kitware.com> wrote:
> Hi Alex,
>
>
> Yes, we maintain ITK 3.20.
>
> That's still the official release of ITK.
>
> Please create a bug in  MANTIS describing the issue.
>
> Assign it to me,
> and if possible indicate what code patch
> from ITKv4 must be applied to ITK 3.20.
>
>
>     Thanks
>
>
>           Luis
>
>
> -----------------------------------------------------------------
> On Tue, Sep 14, 2010 at 11:01 AM, Alexandre GOUAILLARD
> <agouaillard at gmail.com> wrote:
>> hi kent.
>>
>> thanks for your feedback.
>>
>> QEMesh is still alive.
>>
>> The API is supposed to be stable, even though I plan to modify
>> slightly the internals to improve speed (copy) and to help addressing
>> non-manifoldness.
>>
>> I am in the process of moving it out of review, but it impacts a lot
>> of things. I plan to have a branch ready and approved by a few senior
>> developpers by november when we have our next meeting.
>>
>> I will proceed and correct the bug your student found right away in
>> v4. Luis, can you advice how to fix it (if we should) for 3.20. Do we
>> plan a maintenance release for 3.20. What is the backporting policy?
>>
>> thanks in advance.
>>
>> alex.
>>
>>
>> On Tue, Sep 14, 2010 at 3:26 PM, kent williams
>> <norman-k-williams at uiowa.edu> wrote:
>>> This has implications for ITK4, if the review QuadEdgeMesh stuff is being
>>> moved out of review. One of our students got the following compiler error:
>>>
>>> InsightToolkit/Review/itkQuadEd
>>> geMeshDiscretePrincipalCurvaturesEstimator.h:141:
>>> error: ISO C++ says that these are ambiguous, even though the worst
>>> conversion for the first is better than the worst conversion for the second:
>>>
>>> InsightToolkit/Utilities/vxl/core/vnl/vnl_math.h:536: note: candidate 1:
>>> double vnl_math_max(double, double)
>>> InsightToolkit/Utilities/vxl/core/vnl/vnl_math.h:535: note: candidate 2:
>>> float vnl_math_max(float, float)
>>>
>>> The problem is this method of
>>> itk::QuadEdgeMeshDiscretePrincipalCurvatureEstimator:
>>>
>>>  virtual OutputCurvatureType ComputeDelta( )
>>>    {
>>>    return  vnl_math_max( 0., m_Mean * m_Mean - m_Gaussian );
>>>    }
>>>
>>> The type of m_Mean and m_Gaussian is the pixel type of the output mesh
>>> PixelType.  I presume that whomever wrote this code only tried it with one
>>> pixel type (float or double) and if the other type is used, it's too
>>> ambiguous for the compiler.
>>>
>>> 3.20 is closed, and I don't know the status of the review QuadEdgeMesh code.
>>> But it's pretty clear to me that this function could be re-written to be
>>> un-ambiguous, eg:
>>>
>>> virtual OutputCurvatureType ComputeDelta()
>>> {
>>> return vnl_math_max(static_cast<OutputCurvatureType>(0.0),
>>>                                 m_Mean * m_Mean - m_Gaussian);
>>> }
>>>
>>> And I'd feel happier with
>>>
>>> (m_Mean * m_Mean) - m_Gaussian
>>>
>>> As well, because while the compiler always remembers operator precedence, I
>>> have to think 'My Dear Aunt Sally' to understand what that expression means.
>>>
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>> _______________________________________________
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>>
>> Visit other Kitware open-source projects at
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>>
>> Kitware offers ITK Training Courses, for more information visit:
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>>
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>