在 2017年6月6日星期二 UTC-7下午12:07:18，Wolfgang Bangerth写道：
>
> On 06/06/2017 12:10 PM, Weixiong Zheng wrote:
> > It runs in serial. The error occurs when using multiple processors.
>
>
To answer if it really happens when I call compress (), I added a bit of
tracking:
for (unsigned int k=0; k<n_dir; ++k)
{
std::cout << "loc_to_glob mapping cell " << cell->id() << " component "
<< k
<< " on proc " << Utilities::MPI::this_mpi_process (mpi_communicator)
<< std::endl;
local_radio (os.str());
sys_mats[k]->add (local_dof_indices,
local_dof_indices,
local_mats[k]);
}
and
for (unsigned int k=0; k<n_dir; ++k)
{
std::cout << "compress sys_mats begins component " << k
<< " on proc " << Utilities::MPI::this_mpi_process (mpi_communicator)
<< std::endl;
sys_mats[k]->compress (VectorOperation::add);
std::cout << "compress sys_mats ends component " << k
<< " on proc " << Utilities::MPI::this_mpi_process (mpi_communicator)
<< std::endl;
}
To test, I added 2-component test with 4 cells using 2 processors. Here is
the tracking before error messages:
loc_to_glob mapping cell 2_0: component 0 on proc 1
loc_to_glob mapping cell 2_0: component 1 on proc 1
loc_to_glob mapping cell 0_0: component 0 on proc 0
loc_to_glob mapping cell 0_0: component 1 on proc 0
loc_to_glob mapping cell 1_0: component 0 on proc 0
loc_to_glob mapping cell 1_0: component 1 on proc 0
compress sys_mats begins component 0 on proc 0
loc_to_glob mapping cell 3_0: component 0 on proc 1
loc_to_glob mapping cell 3_0: component 1 on proc 1
compress sys_mats begins component 0 on proc 1
compress sys_mats ends component 0 on proc 1
compress sys_mats begins component 1 on proc 1
It looks like compress only gets through for direction-0 on processor 0.
> And it really happens when you call `compress()`?
>
> The only thing I can think of is that you didn't set up the sparsity
> pattern correctly. Can you show us the code that sets up the sparsity
> pattern of these matrices?
>
> Best
> W.
>
> --
> ------------------------------------------------------------------------
> Wolfgang Bangerth email: bang...@colostate.edu
> <javascript:>
> www: http://www.math.colostate.edu/~bangerth/
>
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