[petsc-users] MPI Derived Data Type and Non Blocking MPI Send/Recieve

[Zhenglun (Alan) Wei]

Dear Dr. Brown,
      I'm not quite familiar with VecScatter. I just read its 
explanation; it seems requires that my data is stored as a form of 
vectors (is it the vector in PETSc?). However, my data are stored as 
arrays in C program.
      Is that any problem in MPI or it is likely a problem of my code?

thanks,
Alan
On 9/6/2012 5:44 PM, Jed Brown wrote:
>
> Are you familiar with VecScatter?
>
> On Sep 6, 2012 5:38 PM, "Zhenglun (Alan) Wei" <zhenglun.wei at gmail.com 
> <mailto:zhenglun.wei at gmail.com>> wrote:
>
>     Dear All,
>          I hope you're having a nice day.
>          I met a memory problem for MPI data communication. I guess
>     here is a good place to ask this question since you guys are
>     experts and may experienced the same problem before.
>          I used the MPI derived data type (MPI_Type_contiguous,
>     MPI_Type_vector and MPI_Type_indexed) to communicate data for a
>     simulation of 3D problem. The communication is fine, as I checked
>     every single data it sent and received. However, the problem is
>     that the memory keeps increasing while communication. Therefore, I
>     tested each of these three types. MPI_Type_contiguous does not
>     have any problem; while MPI_Type_vector and MPI_Type_indexed have
>     problem of memory accumulation. I tried to use MPI_Type_free, but
>     it does not help. Have anyone experienced this problem before?
>          Would this be related to the non-blocking MPI communication
>     (MPI_Isend and MPI_Irecv). I have to use this non-blocking
>     communication since the blocking communication is extremely slow
>     when it has a lot of data involved in the communication.
>          Is there any alternative way in PETSc that could do the
>     similar work of MPI derived types?
>
>     thanks,
>     Alan
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20120906/6c80c958/attachment.html>