[Insight-developers] 0008911: Numerical issues in vnl matrix inversion?

[Bill Lorensen]

Tom,

Looks like it is passing on all platforms with the change from float
to double. I'll make the bug as resolved and wait to here from the
reporter before I close it,

Bill


On Mon, Jul 27, 2009 at 1:10 PM, Bill Lorensen<bill.lorensen at gmail.com> wrote:
> Tom,
>
> Sounds good. I'll check in the float-double change in the test and we
> can see how things go tonight.
>
> Bill
>
> On Mon, Jul 27, 2009 at 12:46 PM, Tom
> Vercauteren<tom.vercauteren at m4x.org> wrote:
>> Hi Bill,
>>
>> To me, both options seems fine. It would be great to have a feedback
>> from the bug reporter though.
>>
>> Then if we choose to change the test and use doubles instead of floats
>> we can still use the patch for itk::Matrix if some other machine still
>> shows a failing test.
>>
>> Tom
>>
>> On Mon, Jul 27, 2009 at 18:29, Bill Lorensen<bill.lorensen at gmail.com> wrote:
>>> With your patch, the test passes. However, if I use the original
>>> itkMatrix.h code but change the matlab-related matrices to double, the
>>> test also passes. Looking at the matlab matrix, I think computing the
>>> inverse in double makes sense. Perhaps we should leave itkMatrix alone
>>> and fix the test to use double?
>>>
>>> Bill
>>>
>>>
>>> On Mon, Jul 27, 2009 at 12:00 PM, Bill Lorensen<bill.lorensen at gmail.com> wrote:
>>>> I'll try it on my gcc4.3 system.
>>>>
>>>> On Mon, Jul 27, 2009 at 11:50 AM, Tom
>>>> Vercauteren<tom.vercauteren at m4x.org> wrote:
>>>>> Hi Bill,
>>>>>
>>>>> I was actually writing an email about that exact matter :)
>>>>>
>>>>> A few days ago, I tried to replicate bug 8911
>>>>> http://www.itk.org/Bug/view.php?id=8911
>>>>>
>>>>> I couldn't do it on my machine but since I had the test written, I
>>>>> decided to commit it. Now I see it failing on a few machines. So
>>>>> apparently, bug 8911 can be replicated.
>>>>>
>>>>> I agree that letting vxl folks fix it would be good. Another option
>>>>> would be to try a fix on ITK's side (which would be faster). I already
>>>>> prepared something but cannot currently test whether it works or not.
>>>>> The tentative patch is attached here and to the bug tracker. Could you
>>>>> try it on your system?
>>>>>
>>>>> Thanks,
>>>>> Tom
>>>>>
>>>>> On Mon, Jul 27, 2009 at 17:40, Bill Lorensen<bill.lorensen at gmail.com> wrote:
>>>>>> Tom,
>>>>>>
>>>>>> I see that you checked in a test that exhibits the failing inversion.
>>>>>> It fails on Borland, gcc 4.3 and MAC 4.0. Does it pass on your system?
>>>>>>
>>>>>> Is there a plan to fix this? Perhaps we should we let the vxl folks fix it?
>>>>>>
>>>>>> Bill
>>>>>>
>>>>>
>>>>
>>>
>>
>