[Trilinos-Users] Tpetra CRS matrix repeated fill - howto

[Martin Vymazal]

Hello Mark,

  you say that sumIntoGlobalValues is more efficient than 
insertGlobalValues. However, I still have to do step 1) at least once 
(say during the setup phase). When I omit 1) completely, I end up with 
an exception saying that the matrix has zero columns 
(sumIntoGlobalValues didn't create any entries in the matrix I suppose).

Best regards,

   Martin Vymazal


On 11/24/2014 10:20 PM, Hoemmen, Mark wrote:
> On 11/24/14, 12:00 PM, "trilinos-users-request at software.sandia.gov"
> <trilinos-users-request at software.sandia.gov> wrote:
>> Message: 1
>> Date: Mon, 24 Nov 2014 11:21:42 +0100
>> From: Martin Vymazal <martin.vymazal at vki.ac.be>
>> To: "'trilinos-users at software.sandia.gov'"
>> 	<trilinos-users at software.sandia.gov>
>> Subject: [Trilinos-Users] Tpetra CRS matrix repated fill - howto
>> Message-ID: <4870639.qbSfTX3zYp at tinlaptop>
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Hello,
>>
>> I'm a bit confused about the proper order of steps to fill Tpetra CRS
>> matrix
>> (which is allocated dynamically with a size hint). I need to fill the
>> matrix
>> repeatedly in an iterative procedure. The structure of the matrix will be
>> preserved, only its entries will have different values.
>>
>> Currently I do this:
>> 1) Perform a fake assembly loop over the system and call
>> 'insertGlobalValues'
>> to create corresponding row entries
>> 2) Do the real assembly in each iteration and call 'sumIntoGlobalValues'
>>
>> The documentation says that 'insertGlobalValues' inserts corresponding
>> row
>> values and 'If that entry already exists, add the new value to the old
>> value.'
>> I thought that this means that I could skip step 1) above and just call
>> 'insertGlobalValues' every time I assemble my matrix.
> It is more efficient to use sumIntoGlobalValues (or even
> sumIntoLocalValues if you can) for the assembly loop (repeated instances
> of Step 2 above).
>
>> This is what I got instead:
>>
>> Tpetra::CrsMatrix<double, int, int,
>> KokkosClassic::SerialNode>::insertGlobalValues: new indices exceed
>> statically
>> allocated graph structure.
>>
>> Could you please tell me what is the correct procedure to initialize the
>> entries in Tpetra CRS matrix and then fill it repeatedly?
> This is a known bug in Tpetra::Crs{Graph,Matrix} which I plan to fix once
> I get the chance.  Currently, Tpetra sums repeated entries in each row at
> fillComplete, not as they are inserted.
>
> mfh
>
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