[petsc-users] Question about linking LAPACK library

[­권승리 / 학생 / 항공우주공학과]

Thank you for your reply.

I think I gave an example of an unrealistic problem.

I just wanted to know how to compute the inverse matrix, so I was wondering
if there is an example of computing the inverse matrix in PETSc.

Alternatively, I want to know how to link the LAPACK library.

best,

Seung Lee Kwon

2023년 4월 25일 (화) 오후 6:44, Matthew Knepley <knepley at gmail.com>님이 작성:

> On Mon, Apr 24, 2023 at 11:47 PM ­권승리 / 학생 / 항공우주공학과 <ksl7912 at snu.ac.kr>
> wrote:
>
>> Dear all
>>
>> It depends on the problem. It can have hundreds of thousands of degrees
>> of freedom.
>>
>
> Suppose your matrix was dense and had 1e6 dofs. The work to invert a
> matrix is O(N^3) with a small
> constant, so it would take 1e18 = 1 exaflop to invert this matrix and
> about 10 Terabytes of RAM to store
> it. Is this available to you? PETSc's supports Elemental and SCALAPACK for
> this kind of calculation.
>
> If the system is sparse, you could invert it using MUMPS, SuperLU_dist, or
> Pardiso. Then the work and
> storage depend on the density. There are good estimates for connectivity
> based on regular grids of given
> dimension. The limiting resource here is usually memory, which motivates
> people to try iterative methods.
> The convergence of iterative methods depend on detailed properties of your
> system, like the operator spectrum.
>
>   Thanks,
>
>      Matt
>
>
>> best,
>>
>> Seung Lee Kwon
>>
>> 2023년 4월 25일 (화) 오후 12:32, Barry Smith <bsmith at petsc.dev>님이 작성:
>>
>>>
>>>   How large are the dense matrices you would like to invert?
>>>
>>> On Apr 24, 2023, at 11:27 PM, ­권승리 / 학생 / 항공우주공학과 <ksl7912 at snu.ac.kr>
>>> wrote:
>>>
>>> Dear all
>>>
>>> Hello.
>>> I want to make an inverse matrix like inv(A) in MATLAB.
>>>
>>> Are there some methods to inverse matrix in petsc?
>>>
>>> If not, I want to use the inverse function in the LAPACK library.
>>>
>>> Then, how to use the LAPACK library in petsc? I use the C language.
>>>
>>> Best,
>>>
>>> Seung Lee Kwon
>>>
>>> --
>>> Seung Lee Kwon, Ph.D.Candidate
>>> Aerospace Structures and Materials Laboratory
>>> Department of Mechanical and Aerospace Engineering
>>> Seoul National University
>>> Building 300 Rm 503, Gwanak-ro 1, Gwanak-gu, Seoul, South Korea, 08826
>>> E-mail : ksl7912 at snu.ac.kr
>>> Office : +82-2-880-7389
>>> C. P : +82-10-4695-1062
>>>
>>>
>>>
>>
>> --
>> Seung Lee Kwon, Ph.D.Candidate
>> Aerospace Structures and Materials Laboratory
>> Department of Mechanical and Aerospace Engineering
>> Seoul National University
>> Building 300 Rm 503, Gwanak-ro 1, Gwanak-gu, Seoul, South Korea, 08826
>> E-mail : ksl7912 at snu.ac.kr
>> Office : +82-2-880-7389
>> C. P : +82-10-4695-1062
>>
>
>
> --
> 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
>
> https://www.cse.buffalo.edu/~knepley/
> <http://www.cse.buffalo.edu/~knepley/>
>


-- 
Seung Lee Kwon, Ph.D.Candidate
Aerospace Structures and Materials Laboratory
Department of Mechanical and Aerospace Engineering
Seoul National University
Building 300 Rm 503, Gwanak-ro 1, Gwanak-gu, Seoul, South Korea, 08826
E-mail : ksl7912 at snu.ac.kr
Office : +82-2-880-7389
C. P : +82-10-4695-1062
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