[petsc-users] How to activate the modified Gram-Schmidt orthogonalization process in Fortran?

[Zhang, Hong]

Zhuo,
I'll try to get it done after the incoming release. My hands are full with more urgent tasks at moment. I'll let you know after I'm done.
Thanks for your patience.
Hong

________________________________
From: Zhuo Chen <chenzhuotj at gmail.com>
Sent: Thursday, September 10, 2020 8:41 PM
To: Zhang, Hong <hzhang at mcs.anl.gov>
Cc: petsc-users at mcs.anl.gov <petsc-users at mcs.anl.gov>
Subject: Re: [petsc-users] How to activate the modified Gram-Schmidt orthogonalization process in Fortran?

Hi Hong,

According to that very old thread, KSPGMRESSetOrthogonalization was not implemented in Fortran. I did as you suggested and the compiler will tell me

undefined reference to `kspgmressetorthogonalization_'

I think I will use the -ksp_gmres_modifiedgramschmidt method. Thank you so much!

On Thu, Sep 10, 2020 at 7:32 PM Zhang, Hong <hzhang at mcs.anl.gov<mailto:hzhang at mcs.anl.gov>> wrote:
Zhuo,
Call
KSPSetType(ksp,KSPGMRES);
KSPGMRESSetOrthogonalization(ksp,KSPGMRESModifiedGramSchmidtOrthogonalization);
Hong

________________________________
From: Zhuo Chen <chenzhuotj at gmail.com<mailto:chenzhuotj at gmail.com>>
Sent: Thursday, September 10, 2020 8:17 PM
To: Zhang, Hong <hzhang at mcs.anl.gov<mailto:hzhang at mcs.anl.gov>>
Cc: petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov> <petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov>>
Subject: Re: [petsc-users] How to activate the modified Gram-Schmidt orthogonalization process in Fortran?

Hi Hong,

Thank you very much for your help.

It seems that if I simply append -ksp_gmres_modifiedgramschmidt the warning goes away. However KSPGMRESSetOrthogonalization(ksp,KSPGMRESModifiedGramSchmidtOrthogonalization,ierr) has another issue.

Error: Symbol ‘kspgmresmodifiedgramschmidtorthogonalization’ at (1) has no IMPLICIT type

Is it because the argument is too long? I am using gcc 8.4.0 instead of ifort

On Thu, Sep 10, 2020 at 7:08 PM Zhang, Hong <hzhang at mcs.anl.gov<mailto:hzhang at mcs.anl.gov>> wrote:
Zhuo,
Run your code with option '-ksp_gmres_modifiedgramschmidt'. For example,
petsc/src/ksp/ksp/tutorials
mpiexec -n 2 ./ex2 -ksp_view -ksp_gmres_modifiedgramschmidt
KSP Object: 2 MPI processes
  type: gmres
    restart=30, using Modified Gram-Schmidt Orthogonalization
    happy breakdown tolerance 1e-30
  maximum iterations=10000, initial guess is zero
  tolerances:  relative=0.000138889, absolute=1e-50, divergence=10000.
  left preconditioning
  using PRECONDITIONED norm type for convergence test
PC Object: 2 MPI processes
  type: bjacobi
...

You can call KSPGMRESSetOrthogonalization(ksp,KSPGMRESModifiedGramSchmidtOrthogonalization) in your program.

Hong

________________________________
From: petsc-users <petsc-users-bounces at mcs.anl.gov<mailto:petsc-users-bounces at mcs.anl.gov>> on behalf of Zhuo Chen <chenzhuotj at gmail.com<mailto:chenzhuotj at gmail.com>>
Sent: Thursday, September 10, 2020 7:52 PM
To: petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov> <petsc-users at mcs.anl.gov<mailto:petsc-users at mcs.anl.gov>>
Subject: [petsc-users] How to activate the modified Gram-Schmidt orthogonalization process in Fortran?

Dear Petsc users,

I found an ancient thread discussing this problem.

https://lists.mcs.anl.gov/pipermail/petsc-users/2011-October/010607.html

However, when I add

call KSPSetType(ksp,KSPGMRES,ierr);CHKERRQ(ierr)
call PetscOptionsSetValue(PETSC_NULL_OPTIONS,'-ksp_gmres_modifiedgramschmidt','1',ierr);CHKERRQ(ierr)

the program will tell me

WARNING! There are options you set that were not used!
WARNING! could be spelling mistake, etc!
There is one unused database option. It is:
Option left: name:-ksp_gmres_modifiedgramschmidt value: 1

I would like to know the most correct way to activate the modified Gram-Schmidt orthogonalization process in Fortran. Thank you very much!

Best regards.




--
Zhuo Chen
Department of Physics
University of Alberta
Edmonton Alberta, Canada T6G 2E1
http://www.pas.rochester.edu/~zchen25/


--
Zhuo Chen
Department of Physics
University of Alberta
Edmonton Alberta, Canada T6G 2E1
http://www.pas.rochester.edu/~zchen25/


--
Zhuo Chen
Department of Physics
University of Alberta
Edmonton Alberta, Canada T6G 2E1
http://www.pas.rochester.edu/~zchen25/
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