Is there a quick way for me to find out which version of
PETSc KSPConvergedDefaultCreate() was introduced with?
I'll likely need to conditionally pragma-out these calls for back
compatibility.
Thanks,
Daniel
On Tue, Jan 21, 2025 at 1:16 PM Barry Smith <bsm...@petsc.dev> wrote:
>
> Yes, that can be passed in also with KSPSetConvergenceTest()
>
>
> On Jan 21, 2025, at 4:25 AM, Daniel Stone <daniel.st...@opengosim.com>
> wrote:
>
> That works wonderfully, thanks! Should be paired with
>
> call KSPConvergedDefaultDestroy(ctx,ierr)
>
> I think.
>
> Best Regards,
>
> Daniel
>
>
>
> On Mon, Jan 20, 2025 at 3:20 PM Barry Smith <bsm...@petsc.dev> wrote:
>
>>
>> David,
>>
>> KSPConvergedDefault() now takes a non-NULL context that must be
>> provided. I have attached a modified version of ex5f.F90 that demonstrates
>> how it is constructured before being passed to KSPSetConvergenceTest().
>>
>> Barry
>>
>>
>> > On Jan 20, 2025, at 8:54 AM, Daniel Stone <daniel.st...@opengosim.com>
>> wrote:
>> >
>> > Hello PETSc Community,
>> >
>> > I think I've found a bug -
>> >
>> > Go to $PETSC_DIR/src/ksp/ksp/tutorials/
>> >
>> > open ex5f.F90, and add the following line in MyKSPConverged(), say
>> around line 336:
>> >
>> > call KSPConvergedDefault(ksp,n,rnorm,flag,dummy,ierr)
>> >
>> > It should make sense why someone would want to do this - within a
>> definition of custom convergence behaviour, get the default convergence
>> flags, and, based on certain conditions, overwrite it.
>> >
>> > Now, building and running the exercise, making sure to include the flag
>> to use the custom convergence:
>> >
>> >
>> > boston@boston-SYS-540A-TR:~/DATA_DRIVE/PETSC_DIRS/petsc_3.22/src/ksp/ksp/tutorials$
>> ./ex2f -my_ksp_convergence
>> > [0]PETSC ERROR:
>> ------------------------------------------------------------------------
>> > [0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation,
>> probably memory access out of range[...]
>> >
>> > From my debugging, the issue is at line 1520 of iterativ.c:
>> >
>> > KSPConvergedDefaultCtx *cctx = (KSPConvergedDefaultCtx *)ctx;
>> >
>> > Because a dummy is used for the context object, this cast fails (my
>> debugger says "cannot access memory..." for cctx). Then the crash happens
>> when trying to access members of cctx:
>> >
>> > if (cctx->convmaxits && n >= ksp->max_it) {
>> >
>> >
>> > I'm not sure how to fix it. Crucially, we must note that that this did
>> work in older versions of PETSc - I can repeat this test in 3.19.1, for
>> example, and it works fine - a debugger shows the cast succeeding and
>> producing some
>> > defaulted version of the ctx object, the subsequent crash does not
>> happen, etc.
>> >
>> > Does anybody have any advice for working around this for the time
>> being? A piece of software I work with uses a custom ksp convergence test
>> in the manner described above, and is only functional with older versions
>> of petsc because of this.
>> > Like in ex2f, I have no need of the ctx object, and just as in ex2f, I
>> use 0 instead.
>> >
>> > Things I'll try next: defining a proper ctx object (I use 0, like in
>> ex2f), or looking for some PETSC_NULL_CTX definition somewhere.
>> >
>> > Many Thanks,
>> >
>> > Daniel
>> >
>> >
>> >
>>
>>
>
