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

[Satish Balay]

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>
> 
> 
>