[petsc-dev] [petsc-maint #49008] Problems with VecDotNorm2

[Barry Smith]

  Ok, let's go with it then.

   Thanks

  Barry

On Jul 8, 2010, at 6:59 PM, Satish Balay wrote:

> Barry,
> 
> I've added patch-vecdotnorm2-query.diff to petsc-31 and ran a couple
> of builds with tests - and they ran fine.
> 
> Satish
> 
> On Thu, 8 Jul 2010, Barry Smith wrote:
> 
>> 
>>   Satish,
>> 
>>    Can you try to apply solution 1 to 3.1 and see if the tests are ok?
>> 
>>   Barry
>> 
>> On Jul 8, 2010, at 9:56 AM, Jose E. Roman wrote:
>> 
>>> 
>>> On 07/07/2010, Barry Smith wrote:
>>> 
>>>> 
>>>> On Jul 6, 2010, at 9:49 AM, Jose E. Roman wrote:
>>>> 
>>>>> Dear all,
>>>>> 
>>>>> We at SLEPc have included a custom implementation of vectors that emulates block vectors in the spirit of PetscExt: v=[v1' v2']' where v1 and v2 are PETSc vectors. This is required for some new SLEPc solvers. With this new type of vectors, we avoid the VecGetArray/VecRestoreArray operations, which would imply array copies, and overload any other required operation. The only place outside SLEPc where these vectors are used is as arguments to KSPSolve.
>>>>> 
>>>>> The problem is VecDotNorm2, which is used in KSPSolve_BCGS and KSPSolve_GCR_cycle and invokes VecGetArray. VecDotNorm2 cannot be overloaded as the other functions, since it is not included in the _VecOps table. Therefore we cannot use KSP=bcgsl with our new solvers. A fix for us would be to promote VecDotNorm2 to be a true Vec operation
>>>> 
>>>> 
>>>> I have no objection to upgrading VecDotNorm2() to be a virtual function. 
>>>> 
>>>> 
>>>>> . If possible, it would be nice that the fix would be included in petsc-3.1.
>>>> 
>>>> We really don't like to make such a big change in a patch but if you make the change the change to 3.1 and test it then I have no objection.
>>>> 
>>>> Barry
>>>> 
>>>>> 
>>>>> Thanks,
>>>>> Jose
>>>>> 
>>>>> PS. We plan to release slepc-3.1 in a few weeks.
>>>>> 
>>>>> 
>>>> 
>>> 
>>> I am attaching two possible solutions to our problem.
>>> 
>>> 1) patch-vecdotnorm2-table.diff --> this is the solution suggested initially. The problem is that if it is included in petsc-3.1 then the ABI will be incompatible with previous patches.
>>> 
>>> 2) patch-vecdotnorm2-query.diff --> this uses PetscObjectQueryFunction so that the functionality can be replaced from outside. You may not like this hack but it maintains ABI compatibility.
>>> 
>>> You may decide to put 2) into petsc-release-3.1 and 1) into petsc-dev.
>>> 
>>> Note that both patchfiles are with respect to petsc-release-3.1.
>>> 
>>> Cheers,
>>> Jose
>>> 
>>> 
>>> <patch-vecdotnorm2-query.diff><patch-vecdotnorm2-table.diff>
>> 
>> 
>> 
> 
>