[petsc-users] MatSetValues() for MATMPICUSP

[recrusader]

That's great. Thank you very much, Jed :).

Best,
Yujie

On Sat, Feb 11, 2012 at 11:06 AM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> On Sat, Feb 11, 2012 at 10:58, recrusader <recrusader at gmail.com> wrote:
>
>>     "    ierr = MatCreateMPIAIJ (libMesh::COMM_WORLD,
>>
>>   m_local, n_local,
>>                                 m_global, n_global,
>>                                 PETSC_NULL, (int*) &n_nz[0],
>>                                 PETSC_NULL, (int*) &n_oz[0], &_mat);
>>              CHKERRABORT(libMesh::COMM_WORLD,ierr);
>>
>>       MatSetOption(_mat,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE); //by
>> Yujie
>>       std::cout<<"MatSetOption"<<std::endl;"
>>
>> I run the same codes in CPU and GPU modes (the same parameters except
>> that GPU uses '-vec_type mpicusp -mat_type mpiaijcusp'). I can find
>> "MatSetOption" output from both the modes. Does that mean that the codes
>> set the options for both the modes?
>>
>
> Libmesh is calling MatSetFromOptions() after MatCreateMPIAIJ() which means
> the preallocation information will be lost if the type is changed. The code
> should be written differently
>
>   ierr = MatCreate(comm,A);CHKERRQ(ierr);
>   ierr = MatSetSizes(*A,m,n,M,N);CHKERRQ(ierr);
>   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
>   ierr = MatSetType(*A,MATAIJ);CHKERRQ(ierr);
>   ierr = MatSetOptionsPrefix(*A,optional_prefix);CHKERRQ(ierr);
>   ierr = MatSetFromOptions(*A);CHKERRQ(ierr);
>   ierr = MatMPIAIJSetPreallocation(*A,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
>   ierr = MatSeqAIJSetPreallocation(*A,d_nz,d_nnz);CHKERRQ(ierr);
>
> I can talk to the libmesh developers about making this change.
>
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