Re: [petsc-users] Augmented Linear System

how do I make sure with any form of Schur Complement approach that I hit the correct residual reduction? Thanks Elias -- Dr. Elias Karabelas Universitätsassistent | PostDoc Institut für Mathematik & Wissenschaftlich

Re: [petsc-users] Construct Matrix based on row and column values

= MatAssemblyEnd(D,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr); ierr = VecRestoreArrayRead(u,);CHKERRQ(ierr); ierr = VecRestoreArrayRead(ur,);CHKERRQ(ierr); --Junchao Zhang On Wed, Apr 8, 2020 at 2:17 AM Elias Karabelas mailto:karabelasel...@gmail.com>> wrote: Dear Jed, I'm done implement

Re: [petsc-users] Construct Matrix based on row and column values

gt;fstarm );   VecRestoreArrayRead(_rpseq, &_rpseq_ptr);   VecRestoreArrayRead(_rmseq, &_rmseq_ptr);   VecDestroy(&_rpseq);   VecDestroy(&_rmseq);   //Cleanup   VecDestroy(Rpos);   VecDestroy(Rneg);   VecScatterDestroy(); } On 08/04/2020 18:26, Jed Brown wrote: Elias Karabelas

Re: [petsc-users] Construct Matrix based on row and column values

/2020 15:53, Jed Brown wrote: Thanks; please don't drop the list. I'd be curious whether this operation is common enough that we should add it to PETSc. My hesitance has been that people may want many different variants when working with systems of equations, for example. Elias Karabelas writes

Re: [petsc-users] Construct Matrix based on row and column values

is common enough that we should add it to PETSc. My hesitance has been that people may want many different variants when working with systems of equations, for example. Elias Karabelas writes: Dear Jed, Yes the Matrix A comes from assembling a FEM-convection-diffusion operator over a tetrahedral me

Re: [petsc-users] Construct Matrix based on row and column values

drop the list. I'd be curious whether this operation is common enough that we should add it to PETSc. My hesitance has been that people may want many different variants when working with systems of equations, for example. Elias Karabelas writes: Dear Jed, Yes the Matrix A comes from assembling

Re: [petsc-users] Construct Matrix based on row and column values

Ok I'll try to decipher that. Thought that I would maybe find something in the GAMG routines but I'll be happy to scroll through the ASM stuff :D On 23/03/2020 13:56, Matthew Knepley wrote: On Mon, Mar 23, 2020 at 8:41 AM Elias Karabelas mailto:karabelasel...@gmail.com>> wrote:

Re: [petsc-users] Construct Matrix based on row and column values

Thanks I'll have a look at it. So I understand correctly, that purely algebraic is not the way to go through PETSc here? Cheers Elias On 23/03/2020 13:39, Matthew Knepley wrote: On Mon, Mar 23, 2020 at 8:38 AM Elias Karabelas mailto:karabelasel...@gmail.com>> wrote: On 23/03/2

Re: [petsc-users] Construct Matrix based on row and column values

On 23/03/2020 13:36, Matthew Knepley wrote: On Mon, Mar 23, 2020 at 8:31 AM Elias Karabelas mailto:karabelasel...@gmail.com>> wrote: Dear Matt, I've just found this answer from 2014 https://lists.mcs.anl.gov/pipermail/petsc-users/2014-August/022450.html won

Re: [petsc-users] Construct Matrix based on row and column values

to break it back down to mesh information if possible at all. Best regards Elias On 23/03/2020 13:02, Matthew Knepley wrote: On Mon, Mar 23, 2020 at 7:46 AM Elias Karabelas mailto:karabelasel...@gmail.com>> wrote: Dear Users, I want to implement a FCT (flux corrected transport)

[petsc-users] Construct Matrix based on row and column values

Dear Users, I want to implement a FCT (flux corrected transport) scheme with PETSc. To this end I have amongst other things create a Matrix whose entries are given by L_ij = -max(0, A_ij, A_ji) for i neq j L_ii = Sum_{j=0,..n, j neq i} L_ij where Mat A is an (non-symmetric) Input Matrix

Re: [petsc-users] Question about KSP

, Elias Karabelas <elias.karabe...@medunigraz.at <mailto:elias.karabe...@medunigraz.at>> wrote: Ok maybe I should go a little bit more into detail. I have some stokes problem in a bifurcating Y-tube. Now I would like to enforce some prescribed flux splits at the outlets

[petsc-users] Question about KSP

the preconditioner (like a AMG) of my KSP to handle that kind of MatShell? Kind Regards Elias -- Dr Elias Karabelas Medical University of Graz Institute of Biophysics Harrachgasse 21/IV 8010 Graz, Austria Phone: +43 316 380 7759 Email: elias.karabe...@medunigraz.at Web : http

[petsc-users] Problems with FBCGSR

Hi, I'm using petsc for solving a non symmetric block system with a field-split preconditioner. At the moment I use the fgmres as outer solver. I recently discovered that there is also a flexible BICG variant in petsc. So I wanted to give it a try. However I get strange behaviour when using it.

[petsc-users] Problems with FBCGSR

Hi, I'm using petsc for solving a non symmetric block system with a field-split preconditioner. At the moment I use the fgmres as outer solver. I recently discovered that there is also a flexible BICG variant in petsc. So I wanted to give it a try. However I get strange behaviour when using

Re: [petsc-users] Block Preconditioning

:47 AM, Elias Karabelas elias.karabe...@medunigraz.at wrote: Dear Members, I want to solve a Block System arising from the Discretization of a stabilized Finite Element Formulation of the Stokes System. I have the following Block Structure A -B^T B C The Preconditioner I

Re: [petsc-users] Block Preconditioning

Dear Matt, sorry but I think I haven't understood points 2 and 3 you mentioned. Could you be a bit more specific? Thanks Elias On 28.05.2015 18:02, Matthew Knepley wrote: On Thu, May 28, 2015 at 10:47 AM, Elias Karabelas elias.karabe...@medunigraz.at mailto:elias.karabe...@medunigraz.at

[petsc-users] Block Preconditioning

is, if it is possible to use PCSHELL to define the action of S^-1 as indicated above. Kind Regards Elias Karabelas -- Elias Karabelas, Ph.D. Medical University of Graz Institute of Biophysics Harrachgasse 21/IV 8010 Graz, Austria Phone: +43 316 380 7759 Email: elias.karabe...@medunigraz.at Web : http