[petsc-users] fortran interface to snes matrix-free jacobian

[Yi Hu]

Dear Jed,

Thanks for your reply. I have an analytical one to implement.

Best, Yi

-----Original Message-----
From: Jed Brown <jed at jedbrown.org> 
Sent: Wednesday, December 20, 2023 5:40 PM
To: Yi Hu <y.hu at mpie.de>; petsc-users at mcs.anl.gov
Subject: Re: [petsc-users] fortran interface to snes matrix-free jacobian

Are you wanting an analytic matrix-free operator or one created for you based on finite differencing? If the latter, just use -snes_mf or -snes_mf_operator.

https://petsc.org/release/manual/snes/#jacobian-evaluation

Yi Hu <y.hu at mpie.de> writes:

> Dear PETSc team,
>  
> My  solution scheme relies on a matrix-free jacobian in the SNES solver. I saw the useful C interface like MatCreateSNESMF(), DMSNESCreateJacobianMF(). I am wondering if you have the fortran equivalence?
>  
> I think for my problem in the main program I need to do DMDASNESsetJacobianLocal(DM, INSERT_VALUES, myJacobian, ctx, err_petsc). Then in myJacobian() subroutine I have to create the operator from DMSNESCreateJacobianMF(), and register my own MATOP_MULT from MatShellSetOperation(). Am I correct? 
>  
> Are these fortran subroutines available? I saw an example in ts module 
> as ex22f_mf.F90 which behaves similar as what I would like to do. Because I would like to use ngmres, I then need to stay in the SNES.
>  
> Thanks for your help.
>  
> Best wishes,
> Yi
>
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Stay up to date and follow us on LinkedIn, Twitter and YouTube.

Max-Planck-Institut für Eisenforschung GmbH
Max-Planck-Straße 1
D-40237 Düsseldorf
 
Handelsregister B 2533 
Amtsgericht Düsseldorf
 
Geschäftsführung
Prof. Dr. Gerhard Dehm
Prof. Dr. Jörg Neugebauer
Prof. Dr. Dierk Raabe
Dr. Kai de Weldige
 
Ust.-Id.-Nr.: DE 11 93 58 514 
Steuernummer: 105 5891 1000


Please consider that invitations and e-mails of our institute are 
only valid if they end with …@mpie.de. 
If you are not sure of the validity please contact rco at mpie.de

Bitte beachten Sie, dass Einladungen zu Veranstaltungen und E-Mails
aus unserem Haus nur mit der Endung …@mpie.de gültig sind. 
In Zweifelsfällen wenden Sie sich bitte an rco at mpie.de
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