[vtk-developers] Code review request: biquadratic quadinterpolation

[Marcus D. Hanwell]

Bumping this until someone feels guilty enough to either approve of or
tell me why the patch is bad! Any takers? It will increase coverage -
adds a new test!

On Tue, Jan 28, 2014 at 10:07 AM, Marcus D. Hanwell
<marcus.hanwell at kitware.com> wrote:
> Thanks John, I appended a third commit to the topic that makes the two
> files consistent. I will see if we can get this merged soon as it
> looks correct to me too, and will increase our coverage of some of
> this code thanks to the contributed test code.
>
> On Fri, Jan 24, 2014 at 5:17 PM, John Platt <jcplatt at dsl.pipex.com> wrote:
>> Hi Marcus,
>>
>> I looked at vtkQuadraticQuad::EvaluatePosition() (VTK5.10) . This assumes
>> the same points for the origins of the linear quads as vtkBiQuadraticQuad...
>>
>>    subId 0 :  (    0,    0 ) - point 0,  linear quad { 0, 4, 8, 7 }
>>             1 :  ( 0.5,    0 )            4,                    { 8, 4, 1, 5
>> }  ** inconsistent **
>>             2 :  ( 0.5, 0.5 )            8,                    { 8, 5, 2, 6
>> }
>>             3 :  (    0, 0.5 )            7,                    { 7, 8, 6, 3
>> }
>>
>> It looks like a bug in vtkQuadraticQuad which has been copied into
>> vtkBiQuadraticQuad.
>>
>>
>> John.
>>
>> ----- Original Message ----- From: "Marcus D. Hanwell"
>> <marcus.hanwell at kitware.com>
>> To: "John Platt" <jcplatt at dsl.pipex.com>
>> Cc: "David Thompson" <david.thompson at kitware.com>; "VTK Developers"
>> <vtk-developers at vtk.org>
>> Sent: Friday, January 24, 2014 6:57 PM
>>
>> Subject: Re: [vtk-developers] Code review request: biquadratic
>> quadinterpolation
>>
>>
>>> Hi John,
>>>
>>> Thanks for your input - I really appreciate it. I will see if I hear
>>> back from the contact David Thompson pointed out, and also try to find
>>> some time to look at the vtkQuadraticQuad to ensure they are
>>> consistent.
>>>
>>> Marcus
>>>
>>> On Thu, Jan 23, 2014 at 6:21 PM, John Platt <jcplatt at dsl.pipex.com> wrote:
>>>>
>>>> Hi Marcus,
>>>>
>>>> I tested this change using 5.10 and it did not affect colour mapping,
>>>> cutting or clipping. Unfortunately, I don't do any probing so I cannot
>>>> check
>>>> this.
>>>>
>>>> There would appear to be a dependency on the starting point for the
>>>> linear
>>>> quads with the 'adjust parametric coordinates' section in
>>>> EvaluatePosition(). Here, the parametric coordinates from the linear quad
>>>> are converted to parametric coordinates in the quadratic quad. The
>>>> origins
>>>> of each linear quad are as follows ...
>>>>
>>>>  (    0,    0 ) - point 0
>>>>  ( 0.5,    0 )            4
>>>>  ( 0.5, 0.5 )            8
>>>>  (    0, 0.5 )            7
>>>>
>>>> So I would say that the proposed change is consistent with these origins.
>>>>
>>>> vtkQuadraticQuad uses the same linear quads as the old vtkBiQuadraticQuad
>>>> so
>>>> it could be a problem here also.
>>>>
>>>> HTH
>>>>
>>>> John.
>>>>
>>>> ----- Original Message ----- From: "Marcus D. Hanwell"
>>>> <marcus.hanwell at kitware.com>
>>>> To: "David Thompson" <david.thompson at kitware.com>
>>>> Cc: "VTK Developers" <vtk-developers at vtk.org>
>>>> Sent: Thursday, January 23, 2014 9:16 PM
>>>> Subject: Re: [vtk-developers] Code review request: biquadratic
>>>> quadinterpolation
>>>>
>>>>
>>>>> On Thu, Jan 23, 2014 at 3:48 PM, David Thompson
>>>>> <david.thompson at kitware.com> wrote:
>>>>>>
>>>>>>
>>>>>> Hi Marcus,
>>>>>>
>>>>>>> There is a topic on Gerrit I am having trouble finding a reviewer for,
>>>>>>> http://review.source.kitware.com/#/t/3848/
>>>>>>
>>>>>>
>>>>>>
>>>>>> Soeren Gebbert (soerengebbert at googlemail.com) is the original
>>>>>> developer.
>>>>>> I'm really swamped right now, but it would be great to verify with
>>>>>> Sandia
>>>>>> that the change does not mess with the Exodus reader's numbering of
>>>>>> nodes
>>>>>> within the cell... several changes have done so in the past.
>>>>>>
>>>>> It would be nice to figure out what the expected behavior is too,
>>>>> because this doesn't break any tests I can see. It is a single line
>>>>> change, I can email the original developer but don't have much more
>>>>> time I can put into this.
>>>>>
>>>>> Marcus
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>>>>>
>>>>
>>>>
>>>
>>
>>