[Trilinos-Users] Tpetra::Vector::{replace, sumInto}GlobalValue() crashes

[Nico Schlömer]

>  1. export from overlapping to non-overlapping (to do the summation
> of shared values)
>  2. export (import?) from non-overlapping back to overlapping (to get
> the summed values on all sharing processors)

I guess that would work.

Just to make sure, Mike mentioned some time ago that

> Tpetra supports off-processor contributions in the standard Tpetra::CrsMatrix class.

Is that via the {replace,sumInto}GlobalValues() methods, or are these
methods just calling getLocalElement() just like their Tpetra::Vector
equivalents?

Cheers,
Nico





On Thu, 19 Aug 2010 08:21:46 -0600, "Williams, Alan B"
<william at sandia.gov> wrote:
> Nico,
> 
> I think you need two vectors, one with the overlap map and one with a
> non-overlapping map. Then you would import/export between those two
> vectors.
> I think you would actually have to do two operations:
>  1. export from overlapping to non-overlapping (to do the summation
> of shared values)
>  2. export (import?) from non-overlapping back to overlapping (to get
> the summed values on all sharing processors)
> 
> Alan
> 
> 
>> -----Original Message-----
>> From: trilinos-users-bounces at software.sandia.gov [mailto:trilinos-
>> users-bounces at software.sandia.gov] On Behalf Of Nico Schlömer
>> Sent: Wednesday, August 18, 2010 11:37 PM
>> To: Baker, Christopher G.
>> Cc: trilinos-users at software.sandia.gov
>> Subject: Re: [Trilinos-Users] Tpetra::Vector::{replace,
>> sumInto}GlobalValue() crashes
>>
>> Thanks for the hint, Chris.
>> In fact, I've been playing around with import/export, but somehow I
>> can't seem to get things straight. I'm sure you already know what's
>> wrong when I'm doing the following:
>> I have a vector x with an overlapping map, and I'd like the sum of all
>> the overlaps to be present on all nodes. What I did was
>>
>>   Tpetra::Export<ORD> exporter( x->getMap(), x->getMap() );
>>   x->doExport( *x, exporter, Tpetra::ADD );
>>
>> I'm reading: Export all of what's in x into x, and add the overlaps;
>> apparently it doesn't work this way, though.
>> Got a quick hint?
>>
>> Cheers,
>> Nico
>>
>>
>>
>>
>>
>> On Wed, 18 Aug 2010 20:45:41 -0400, "Baker, Christopher G."
>> <bakercg at ornl.gov> wrote:
>> > My apologies, Nico. You are correct; in both cases, local/global
>> > replace/sum works only on entries on the node. The only difference is
>> > a translation between local and global, as you correctly surmised. I
>> > have added a note to this effect in the documentation of these class
>> > methods.
>> >
>> > If you want to Tpetra to handle the communication for you, I would
>> > point you towards the import/export capability supported by Vector
>> and
>> > MultiVector.
>> >
>> > Chris
>> >
>> >
>> > On 8/18/10 7:11 PM, "Nico Schlömer" <nico.schloemer at ua.ac.be> wrote:
>> >
>> > Okay so,
>> >
>> > I noticed that guarding the {replace, sumInto}GlobalValue() like
>> >
>> > ===================== *snip* =====================
>> > if ( map->getLocalElement(i0) !=
>> Teuchos::OrdinalTraits<ORD>::invalid()
>> > )
>> >     x->replaceGlobalValue( i0, val );
>> > ===================== *snap* =====================
>> >
>> > makes the the corruption go away, indicating that the only thing
>> > {replace, sumInto}GlobalValue() does for me is calling
>> getLocalElement()
>> > on the map before insertion.
>> > Fair enough, I'm gonna need to make sure then that the corresponding
>> > map allows access to this particular element.
>> >
>> > Cheers,
>> > Nico
>> >
>> >
>> >
>> >
>> >
>> > On Wed, 18 Aug 2010 18:36:24 -0400, Nico Schlömer
>> > <nico.schloemer at ua.ac.be> wrote:
>> >> Hi,
>> >>
>> >> I'm experiencing some ungraceful crashes here using either of
>> >>
>> >>    Tpetra::Vector::replaceGlobalValue()
>> >>    Tpetra::Vector::sumIntoGlobalValue()
>> >>
>> >> with something like
>> >>
>> >> ============================== *snip* ==============================
>> >> *** glibc detected ***
>> >> ../build/mpi/executables/piro-driver/piro-driver.exe: double free or
>> >> corruption (out): 0x00000000028271c0 ***
>> >> ======= Backtrace: =========
>> >> /lib/libc.so.6(+0x72966)[0x7f2cefbcb966]
>> >> /lib/libc.so.6(cfree+0x6c)[0x7f2cefbd071c]
>> >> [...]
>> >> ============================== *snap* ==============================
>> >>
>> >> Their local equivalents work all right.
>> >>
>> >> This is with Trilinos 10.4 on a simple two core build, openmpi
>> 1.4.1,
>> >> GCC 4.4.3.
>> >>
>> >> Anyone with similar experiences?
>> >>
>> >> Cheers,
>> >> Nico
>> >>
>> >>
>> >> _______________________________________________
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>> >
>> >
>> >
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>>
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