[petsc-users] Custom vector owenrship ranges

[Mohammad Bahaa]

the second approach of the MPI vector did it for me, thanks


On Tue, Mar 18, 2014 at 3:20 PM, Mohammad Bahaa <m.bahaa.eldein at gmail.com>wrote:

> Forgive me as my expression "sum up" was misguiding or misplaced, I didn't
> mean to literally sum the values in the vectors, I meant I want to put all
> values from each local vector into one global vector that can be accessed
> by all processes, "COMM_WORLD" communicator for instance
>
>
> On Tue, Mar 18, 2014 at 3:09 PM, Matthew Knepley <knepley at gmail.com>wrote:
>
>> On Tue, Mar 18, 2014 at 7:53 AM, Mohammad Bahaa <m.bahaa.eldein at gmail.com
>> > wrote:
>>
>>> I'm using "PETSC_COMM_SELF" communicator for running n serial
>>> independent processes, I need to sum up a certain vector from the n
>>> processes in one vector, however, vectors involved in each process vary in
>>> size, and I couldn't find any function to define custom ownership ranges,
>>> so assuming I have a 4 processes run with each computing an "x" vector as
>>> follows:
>>>
>>> 1. process (1) with x of length 51
>>> 2. process (2) with x of length 49
>>> 3. process (3) with x of length 52
>>> 4. process (4) with x of length 48
>>>
>>
>> Let your local length be n, so that on proc 3 n== 52. Then
>>
>>   VecCreate(comm, &v);
>>   VecSetSizes(v, n, PETSC_DETERMINE);
>>   VecSetFromOptions(v);
>>   <fill up v>
>>   VecSum(v, &sum);
>>
>> You could also make a parallel Vec from your Seq vecs:
>>
>>   VecGetArray(lv, &array);
>>   VecCreateMPIWithArray(comm, 1, n, PETSC_DETERMINE, array, &v);
>>
>>   Thanks,
>>
>>      Matt
>>
>>
>>> The processes sum up to 100 elements, when I define a vector "x_all" of
>>> size "100" with "PETSC_COMM_WORLD" communicator, the ownership ranges
>>> are equal, which isn't the case, how to customize them ?
>>>
>>> --
>>> Mohamamd Bahaa ElDin
>>>
>>
>>
>>
>> --
>> 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
>>
>
>
>
> --
> Mohamamd Bahaa ElDin
>



-- 
Mohamamd Bahaa ElDin
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