[Trilinos-Users] [EXTERNAL] Re: Tpetra and threads

[Zheng Da]

Is the git repo available for everyone?

$ git clone https://software.sandia.gov/trilinos/repositories/publicTrilinos
Cloning into 'publicTrilinos'...
fatal: unable to access
'https://software.sandia.gov/trilinos/repositories/publicTrilinos/':
server certificate verification failed. CAfile:
/etc/ssl/certs/ca-certificates.crt CRLfile: none

On Mon, Apr 13, 2015 at 5:37 PM, Hoemmen, Mark <mhoemme at sandia.gov> wrote:
> public git repo (see trilinos.org)
>
> On 4/13/15, 3:26 PM, "Zheng Da" <zhengda1936 at gmail.com> wrote:
>
>>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
>>>
>>> _______________________________________________
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>>> Trilinos-Users at software.sandia.gov
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>