[petsc-dev] Weird interaction between VecDuplicate and VecSetBlockSize

[Barry Smith]

On Mar 30, 2012, at 12:44 PM, Lisandro Dalcin wrote:

> On 30 March 2012 19:34, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> 
>> On Mar 30, 2012, at 11:07 AM, Lisandro Dalcin wrote:
>> 
>>> On 30 March 2012 19:00, Lisandro Dalcin <dalcinl at gmail.com> wrote:
>>>> On 30 March 2012 18:20, Blaise Bourdin <bourdin at lsu.edu> wrote:
>>>>> 
>>>>> On Mar 30, 2012, at 10:13 AM, Jed Brown wrote:
>>>>> 
>>>>> The PetscLayout is shared. It should probably not be allowed to change block
>>>>> size after duplicating.
>>>>> 
>>> 
>>> Actually, reading my previous reply, I did not expressed it well. I DO
>>> AGREE with you that blocksizes should not be allowed to change once
>>> set for first time. However, I think PETSc do have some code around
>>> (in PC?) relying on this and unashamedly changing the bs of an INPUT
>>> vector! If that was fixed, then we can disable changing bs for Vec.
>>> But as long as we need to support this misfeature, at least let's try
>>> to do better around the lines of my patch (BTW, I'm not sure how to
>>> handle the blocked local to global mapping.... perhaps we can
>>> reconstruct another one?)
>> 
>> 
>>   Let's locate all the code that changes the block size (after it is set) and eradicate it, then we won't need this bad patch.
>> 
> 
> I think I complained about this long, long ago:
> 
> $ grep VecSetBlockSize -nR src/ksp/pc/
> src/ksp/pc/impls/fieldsplit/fieldsplit.c:637:  ierr =
> VecSetBlockSize(x,jac->bs);CHKERRQ(ierr);
> src/ksp/pc/impls/fieldsplit/fieldsplit.c:638:  ierr =
> VecSetBlockSize(y,jac->bs);CHKERRQ(ierr);
> src/ksp/pc/impls/fieldsplit/fieldsplit.c:710:  ierr =
> VecSetBlockSize(x,jac->bs);CHKERRQ(ierr);
> src/ksp/pc/impls/fieldsplit/fieldsplit.c:711:  ierr =
> VecSetBlockSize(y,jac->bs);CHKERRQ(ierr);
> 

committed changeset 22837:cc05aac4b5fb   Why does hg still print that meaningless number?


Removed setting of vector block sizes in PCFIELDSPLIT, if specific block sizes are needed and do not match the PC will \
error out with appropriate message

  Barry


> 
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> Lisandro Dalcin
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