[petsc-users] Equivalent to MatGetColumnVector for rows?

2016-10-19 Thread Jeremy Theler
with MatGetRow() that seems to work but it is some lame I am even embarrased of sharing with the list what I have done. Any suggestion is welcome. Thanks -- jeremy theler www.seamplex.com

Re: [petsc-users] Equivalent to MatGetColumnVector for rows?

2016-10-20 Thread Jeremy Theler
ply this matrix by > the solution vector you will get a "short" vector that on each process > contains the "reaction" for each each of the "removed row" on that process. > > Easy to implement. > >Barry > > > On Oct 19, 2016, at 4

Re: [petsc-users] GAMG

2016-10-28 Thread Jeremy Theler
re is something wrong with your matrix. Use any solver and > verify that you like the solution first. > > On Fri, Oct 28, 2016 at 9:13 AM, Jeremy Theler <jer...@seamplex.com> > wrote: > Hi! I want to use PCGAMG as a preconditioner for a 3D linear > elastic

Re: [petsc-users] GAMG

2016-10-28 Thread Jeremy Theler
> > If I do not call PCSetCoordinates() the error goes away but > convergence > is slow. > Is it possible that your coordinates lie on a 2D surface? All this > does is make the 6 basis vectors > for translations and rotations. You can just make these yourself and

[petsc-users] GAMG

2016-10-28 Thread Jeremy Theler
Hi! I want to use PCGAMG as a preconditioner for a 3D linear elasticity problem (displacement-based FEM formulation) over an unstructured grid. I am not using DMPlex, I just build the stiffness matrix myself and pass it to PETSc. I set MatSetBlockSize() to 3 and pass the node coordinates through

Re: [petsc-users] GAMG

2016-10-28 Thread Jeremy Theler
On Fri, 2016-10-28 at 09:46 -0400, Mark Adams wrote: > Please run with -info and grep on GAMG. > [0] PCSetUp_GAMG(): level 0) N=120726, n data rows=3, n data cols=6, nnz/row (ave)=41, np=1 [0] PCGAMGFilterGraph(): 99.904% nnz after filtering, with threshold 0., 13.7468 nnz ave. (N=40242)

Re: [petsc-users] GAMG

2016-10-31 Thread Jeremy Theler
On Mon, 2016-10-31 at 08:44 -0600, Jed Brown wrote: > > After understanding Matt's point about the near nullspace (and reading > > some interesting comments from Jed on scicomp stackexchange) I did built > > my own vectors (I had to take a look at MatNullSpaceCreateRigidBody() > > because I found

Re: [petsc-users] GAMG

2016-10-28 Thread jeremy theler
Are the > elements badly stretched? > > Do this again with these parameters: > > -mg_levels_ksp_type chebyshev > -mg_levels_esteig_ksp_type cg > -mg_levels_esteig_ksp_max_it 10 > ​​ > -mg_levels_ksp_chebyshev_esteig 0,.1,0,1.05 > -gamg_est_ksp_type cg > > > On Fri,

Re: [petsc-users] Autoconf tests

2016-10-12 Thread jeremy theler
I once made a quick hack, maybe you can start your dirty work from here https://bitbucket.org/wasora/wasora/src/5a88abbac1a846f2a6ed0b4e585f6f3c0fedf2e7/m4/petsc.m4?at=default=file-view-default -- jeremy On Tue, Oct 11, 2016 at 5:31 PM Barry Smith wrote: > >You don't

[petsc-users] getting the near nullspace from PCSetCoordinates

2017-01-02 Thread Jeremy Theler
when I ask MatGetNearNullSpace(matrix) passing the problem matrix after setting PCSetCoordinates(pc) I get: error: PETSc error 85-0 'Null Object: Parameter # 1' in /home/gtheler/libs/petsc-3.7.4/src/mat/interface/matnull.c MatNullSpaceGetVecs:64 thanks -- Jeremy Theler www.seamplex.com

Re: [petsc-users] pc_gamg_threshol

2017-01-05 Thread Jeremy Theler
that describes the methods and not just the implementation as the source code at gamg/util.c so I can better understand what is going on. Thanks -- Jeremy Theler www.seamplex.com On Thu, 2017-01-05 at 09:18 -0500, Mark Adams wrote: > You want the bottom of page 84 in the manual. > > On W

[petsc-users] pc_gamg_threshol

2017-01-04 Thread Jeremy Theler
Hi! Any reference to what does -pc_gamg_threshold mean and/or? -- Jeremy Theler www.seamplex.com

Re: [petsc-users] pc_gamg_threshol

2017-01-04 Thread Jeremy Theler
* Any reference to what pc_gamg_treshold means and/or does? On Wed, 2017-01-04 at 18:13 -0300, Jeremy Theler wrote: > Hi! Any reference to what does -pc_gamg_threshold mean and/or? >