[petsc-users] vector outer product

[Yifei Li]

On Thu, Aug 9, 2012 at 10:59 PM, Matthew Knepley <knepley at gmail.com> wrote:

> On Thu, Aug 9, 2012 at 9:56 PM, Yifei Li <yifli82 at gmail.com> wrote:
>
>> Matt,
>>
>> I'm new to PETSC, can you pls explain what you mean by 'keep it in
>> unassembled form'?
>>
>
> Just keep two vectors, u^T v, instead of the dense matrix.
>
>
But I need the result of the outer product (e.g, A) for further calculation
(e.g., A*W).

>
>
>    Matt
>
>
>> A small example would be nice too. Thanks
>>
>> Yifei
>>
>> On Thu, Aug 9, 2012 at 9:15 PM, Matthew Knepley <knepley at gmail.com>wrote:
>>
>>> On Thu, Aug 9, 2012 at 5:39 PM, Yifei Li <yifli82 at gmail.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I did not find any function doing this in the manual.  Could someone
>>>> suggest a good way to do this?
>>>>
>>>
>>> That gives a dense matrix. You would never want to do this. You would
>>> keep it in unassembled form.
>>>
>>>     Matt
>>>
>>>
>>>>
>>>> Thanks
>>>>
>>>> Yifei
>>>>
>>>
>>>
>>>
>>> --
>>> 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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