[petsc-users] VecScatter in 'add' mode?

[Matthew Knepley]

On Wed, Sep 28, 2011 at 4:15 PM, Hui Zhang <mike.hui.zhang at hotmail.com>wrote:

>
> On Sep 28, 2011, at 6:08 PM, Matthew Knepley wrote:
>
> On Wed, Sep 28, 2011 at 4:05 PM, Hui Zhang <mike.hui.zhang at hotmail.com>wrote:
>
>>
>> On Sep 28, 2011, at 5:58 PM, Matthew Knepley wrote:
>>
>> On Wed, Sep 28, 2011 at 3:54 PM, Hui Zhang <mike.hui.zhang at hotmail.com>wrote:
>>
>>> Hi all,
>>>
>>> When using
>>>
>>> PetscErrorCode  VecScatterCreate(Vec xin,IS ix,Vec yin,IS iy,VecScatter *newctx)
>>>
>>> I want to add those values of xin to the original values of yin.
>>>
>>> Is there a way to do this without copy of yin?
>>>
>>> I am not sure what you mean here. Do you want xin == yin?
>>
>>
>> No, I mean part of xin is going to be added to part of yin.
>>
>
> Alright. We do not make a copy of yin.
>
>
> My fault, the question is not clear. I mean 'add' as 'sum'. I want the
> resultant 'yin' to have values
> y(iy) = y(iy) + x(ix).
>

Use ADD_VALUES in VecScatterBegin/End()

   Matt


>    Matt
>
>
>
>>   Matt
>>
>>
>>> Thanks!
>>>
>>> Hui
>>>
>>> --
>> 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
>
>
>


-- 
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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