[petsc-users] about Singular value

[Matthew Knepley]

On Sun, Oct 30, 2011 at 11:24 AM, behzad baghapour <
behzad.baghapour at gmail.com> wrote:

> Then it would be an approximation to the Preconditioned Matrix (JM^(-1) or
> M^(-1)J) up to the dimension of the Krylov subspace?


Yes.

   Matt


> On Sun, Oct 30, 2011 at 2:47 PM, Matthew Knepley <knepley at gmail.com>wrote:
>
>> On Sun, Oct 30, 2011 at 7:49 AM, behzad baghapour <
>> behzad.baghapour at gmail.com> wrote:
>>
>>> Dear all,
>>>
>>> What is the procedure or method to calculate Extreme Singular Values
>>> when calling KSPComputeExtremeSingularValues( )?
>>>
>>
>> Are you asking what is done internally? We call LAPACK SVD on the
>> Hermitian matrix made by the Krylov method.
>>
>>    Matt
>>
>>
>>> Thanks, B. B.
>>>
>>
>> --
>> 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
>>
>
>
>
> --
> ==================================
> Behzad Baghapour
> Ph.D. Candidate, Mechecanical Engineering
> University of Tehran, Tehran, Iran
> https://sites.google.com/site/behzadbaghapour
> Fax: 0098-21-88020741
> ==================================
>
>


-- 
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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