[Trilinos-Users] Tpetra and threads

[Zheng Da]

Hello Mark,

Tpetra Lesson 07 doesn't exist in tpetra/core/example of v11.14.1.
Which version of Trilinos should I look at?

Thanks,
Da

On Mon, Apr 13, 2015 at 4:30 PM, Hoemmen, Mark <mhoemme at sandia.gov> wrote:
>
>
> On 4/13/15, 12:00 PM, "trilinos-users-request at software.sandia.gov"
> <trilinos-users-request at software.sandia.gov> wrote:
>>Message: 1
>>Date: Mon, 13 Apr 2015 15:49:21 +0200
>>From: Martin Vymazal <martin.vymazal at vki.ac.be>
>>To: trilinos-users at software.sandia.gov
>>Subject: [Trilinos-Users] Tpetra and threads
>>Message-ID: <2697171.BCGQzWlqIO at tinlaptop>
>>Content-Type: text/plain; charset="us-ascii"
>>
>>Hello,
>>
>> I have a toy FE problem, for which I use Tpetra map, and Tpetra CRS
>>matrix to
>>store and solve the linear system. Everything works fine when I run the
>>code in
>>serial, but when I try assembly with 2 threads (using std::thread from
>>C++11),
>>I get memory crashes.
>>
>>What I'm trying to do is this:
>>1) Initialize system matrix (in serial)
>>2) Run assembly with multiple threads (that I launched outside of
>>Trilinos)
>>3) When assembly is finished and threads join, solve the linear system
>>(in
>>serial again)
>>
>>I understand that this is not the best/most optimal way, but all I wanted
>>to
>>try is a simple test and it would really help me if I could ask
>>Tpetra/Kokkos
>>not to get in my way. From the output it seems that Kokkos starts
>>automatically its own thread and it probably does not like the fact that
>>later
>>on, different number of threads accumulate in the system matrix.
>>
>>I get the following:
>>
>>Kokkos::HostSpace::decrement( 0x168c180 ) ERROR :  memory not being
>>tracked
>>
>>I searched for examples how to set the Tpetra map parameters in order to
>>control the number of threads, but they all only show how (not) to use
>>MPI,
>>nothing said about multithreading ... Is what I'm trying to do possible?
>>Can I
>>tell Trilinos 'not to worry' about my threads?
>>
>>Thank you for your help,
>>
>> Martin Vymazal
>
> Hi Martin,
>
> Please see Tpetra Lesson 07 (in tpetra/core/example) for a demonstration
> of thread-parallel sparse matrix construction and fill.  The interface of
> Tpetra::CrsMatrix does not promise thread safety; we have a lower-level
> interface (which the example uses) that does.
>
> mfh
>
> _______________________________________________
> Trilinos-Users mailing list
> Trilinos-Users at software.sandia.gov
> https://software.sandia.gov/mailman/listinfo/trilinos-users