[petsc-users] (no subject)

[Matthew Knepley]

On Thu, Sep 15, 2016 at 4:23 AM, Ji Zhang <gotofd at gmail.com> wrote:

> Thanks Matt. It works well for signal core. But is there any solution if I
> need a MPI program?
>

It unclear what the stuff below would mean in parallel.

If you want to assemble several blocks of a parallel matrix that looks like
serial matrices, then use


http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatGetLocalSubMatrix.html

  Thanks,

     Matt


> Thanks.
>
> Wayne
>
> On Tue, Sep 13, 2016 at 9:30 AM, Matthew Knepley <knepley at gmail.com>
> wrote:
>
>> On Mon, Sep 12, 2016 at 8:24 PM, Ji Zhang <gotofd at gmail.com> wrote:
>>
>>> Dear all,
>>>
>>> I'm using petsc4py and now face some problems.
>>> I have a number of small petsc dense matrices mij, and I want to
>>> construct them to a big matrix M like this:
>>>
>>>          [  m11  m12  m13  ]
>>>     M =  |  m21  m22  m23  |   ,
>>>          [  m31  m32  m33  ]
>>> How could I do it effectively?
>>>
>>> Now I'm using the code below:
>>>
>>>     # get indexes of matrix mij
>>>     index1_begin, index1_end = getindex_i( )
>>>     index2_begin, index2_end = getindex_j( )
>>>     M[index1_begin:index1_end, index2_begin:index2_end] = mij[:, :]
>>> which report such error messages:
>>>
>>>     petsc4py.PETSc.Error: error code 56
>>>     [0] MatGetValues() line 1818 in /home/zhangji/PycharmProjects/
>>> petsc-petsc-31a1859eaff6/src/mat/interface/matrix.c
>>>     [0] MatGetValues_MPIDense() line 154 in
>>> /home/zhangji/PycharmProjects/petsc-petsc-31a1859eaff6/src/m
>>> at/impls/dense/mpi/mpidense.c
>>>
>>
>> Make M a sequential dense matrix.
>>
>>    Matt
>>
>>
>>>     [0] No support for this operation for this object type
>>>     [0] Only local values currently supported
>>>
>>> Thanks.
>>>
>>>
>>> 2016-09-13
>>> Best,
>>> Regards,
>>> Zhang Ji
>>> Beijing Computational Science Research Center
>>> E-mail: gotofd at gmail.com
>>>
>>>
>>>
>>
>>
>> --
>> What most experimenters take for granted before they begin their
>> experiments is infinitely more interesting than any results to which their
>> experiments lead.
>> -- Norbert Wiener
>>
>
>


-- 
What most experimenters take for granted before they begin their
experiments is infinitely more interesting than any results to which their
experiments lead.
-- Norbert Wiener
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