Hi Jed,
I do not have a petsc/dev or petsc/next compiled (I just use petsc
3.5.2), but Patrick have one for sure. He should be able to try the
patch sooner than I.
Patrick, would you give it a try please?
Thanks,
Eric
On 10/09/2014 11:41 AM, Jed Brown wrote:
Hi, Eric. Fabian reported this a couple days ago (all, petsc-users is
preferred so that people can see recent discussion).
Thanks for linking to Patrick's report. I have extended it to simplify
the code a bit and reduce synchronization, but I don't have a test case
handy and I'm about to board a plane. Could you try 'next' (or
'placasse/VecGetSubVector' in petsc.git, which has my follow-up commits)
to let me know if it works for you.
https://bitbucket.org/petsc/petsc/issue/75/vecrestoresubvector-silently-ignores-non
Eric Chamberland <[email protected]> writes:
Hi,
I noticed it because I got a strange behavior when computing y=Ax with
(a wrongly) non-contiguous stride in parallel. Normally, the
VecRestoreSubVector should have exited with an error ("Unhandled case,
values have been changed and need to be copied back into X) but didn't,
resulting in a silently wrong result (ouch).
I corrected my code to define a contiguous stride, which "bypass" the
bug in VecRestoreSubVector and now I hopefully compute the correct result.
You may be interested by:
https://bitbucket.org/placasse/petsc/commits/4e4323587ad9148c29ba9101e5030629f073700c
By the way, if I have no local unknowns on a process, shall the stride
*always* be considered locally contiguous? (this is my initial error on
how to define a stride when no unknowns are locally owned).
Thanks,
Eric
