[petsc-users] To store the matrix.

[Hong Zhang]

Rebecca,

We have  private routines MatConvertToTriples_xxx_xxx()
in ~petsc/src/mat/impls/aij/mpi/mumps/mumps.c
which convert petsc seqaij and mpiaij to triples: row[], col[], val[] .
You may take a look at these routines.

Hong

On Thu, Jul 14, 2011 at 1:37 PM, Xuefei (Rebecca) Yuan <xyuan at lbl.gov> wrote:
> Dear Matt and Jed,
> Thanks very much! That helps!
> Best regards,
> Rebecca
>
>
> On Jul 14, 2011, at 11:36 AM, Matthew Knepley wrote:
>
> On Thu, Jul 14, 2011 at 6:30 PM, Xuefei (Rebecca) Yuan <xyuan at lbl.gov>
> wrote:
>>
>> Hi Jed,
>> I need to have this form for the simple input for PDSLin.
>> What do you mean by "COO"?
>> Any examples to show how to pull that new array for reading from the AIJ
>> structure?
>
> First use MatGetSubmatrix() to pull the whole matrix into proc 0 if you are
> in parallel.
> Then you MatGetRow() for each row, and write each entry in your form.
>    Matt
>
>>
>> Thanks a lot!
>> R
>> On Jul 14, 2011, at 11:28 AM, Jed Brown wrote:
>>
>> On Thu, Jul 14, 2011 at 13:18, Xuefei (Rebecca) Yuan <xyuan at lbl.gov>
>> wrote:
>>>
>>> I would like to store this sparse MXN matrix A in the following form:
>>> ....................................................
>>>
>>> line1:  M       N       numberofnonzeros
>>> line2:  i       j       value
>>> line3:  i       j       value
>>
>> This "COO" format is not an efficient representation. Why do you want to
>> store it this way?
>> (You can produce this by getting the AIJ structure, allocating a new array
>> for the row indices, and filling it redundantly from the AIJ structure.
>
>
>
> --
> 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
>
>