[petsc-users] Call KSPConvergedDefault from Fortran

[Natacha BEREUX]

Dear PETSc users,


I am using PETSc Fortran API.
I try to solve a linear system, and would like to define my own convergence
test.
More precisely, my convergence test calls the default convergence test
and then checks the true residual norm :
subroutine MyKSPConverged(ksp,n,rnorm,flag,dummy,ierr)

implicit none

#include <petsc/finclude/petscsys.h>
#include <petsc/finclude/petscvec.h>
#include <petsc/finclude/petscksp.h>

KSP ksp
PetscErrorCode ierr
PetscInt n,dummy
KSPConvergedReason flag
PetscReal rnorm, true_rnorm
Vec true_res
!
call KSPConvergedDefault(ksp,n,rnorm,flag,PETSC_NULL_OBJECT,ierr)
!
! If convergence test succeeds
if ( (flag == KSP_CONVERGED_ATOL) .or. &
& (flag == KSP_CONVERGED_RTOL)) then
! Compute true residual
call KSPBuildResidual( ksp , PETSC_NULL_OBJECT, &
& PETSC_NULL_OBJECT, true_res, ierr )
! Compute true residual norm
call VecNorm(true_res,NORM_2,true_rnorm,ierr)
! And check again convergence with respect to the true residual norm
call KSPConvergedDefault(ksp,n,true_rnorm,flag, &
& PETSC_NULL_OBJECT, ierr)
! Free memory
call VecDestroy(true_res, ierr)
endif
!
ierr = 0

end

I get the following error message

[0]PETSC ERROR: --------------------- Error Message
--------------------------------------------------------------
[0]PETSC ERROR: Null argument, when expecting valid pointer
[0]PETSC ERROR: Convergence context must have been created with
KSPConvergedDefaultCreate()
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for
trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.6.2, Oct, 02, 2015

I understand that I should have call KSPConvergedDefaultCreate() before
calling KSConvergedDefault( ....)

Am I right ?

If so what is the Fortran calling sequence for KSPConvergedDefaultCreate ?
It is supposed to return a valid pointer and I don't succeed in doing so
from Fortran.

If you have any idea, I'd greatly appreciate it
Thank you!
Natacha


PS I have attached my code (it's a slightly modified version of ex2f.F
showing the convergence test code )

[Barry Smith]

It will be very similar to usage from C. You should be able to do something like

PetscFortranAddress ctx

call KSPConvergedDefaultCreate(ctx,ierr)

call KSPMonitorSet(ksp, MyKSPConverged,ctx,kspconvergeddefaultdestroy,ierr)

then in your MyKSPConverged pass the argument called "dummy" to the default monitor.

Barry

Post by Natacha BEREUX
Dear PETSc users,
I am using PETSc Fortran API.
I try to solve a linear system, and would like to define my own convergence test.
More precisely, my convergence test calls the default convergence test
subroutine MyKSPConverged(ksp,n,rnorm,flag,dummy,ierr)
implicit none
#include <petsc/finclude/petscsys.h>
#include <petsc/finclude/petscvec.h>
#include <petsc/finclude/petscksp.h>
KSP ksp
PetscErrorCode ierr
PetscInt n,dummy
KSPConvergedReason flag
PetscReal rnorm, true_rnorm
Vec true_res
!
call KSPConvergedDefault(ksp,n,rnorm,flag,PETSC_NULL_OBJECT,ierr)
!
! If convergence test succeeds
if ( (flag == KSP_CONVERGED_ATOL) .or. &
& (flag == KSP_CONVERGED_RTOL)) then
! Compute true residual
call KSPBuildResidual( ksp , PETSC_NULL_OBJECT, &
& PETSC_NULL_OBJECT, true_res, ierr )
! Compute true residual norm
call VecNorm(true_res,NORM_2,true_rnorm,ierr)
! And check again convergence with respect to the true residual norm
call KSPConvergedDefault(ksp,n,true_rnorm,flag, &
& PETSC_NULL_OBJECT, ierr)
! Free memory
call VecDestroy(true_res, ierr)
endif
!
ierr = 0
end
I get the following error message
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: Null argument, when expecting valid pointer
[0]PETSC ERROR: Convergence context must have been created with KSPConvergedDefaultCreate()
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.6.2, Oct, 02, 2015
I understand that I should have call KSPConvergedDefaultCreate() before calling KSConvergedDefault( ....)
Am I right ?
If so what is the Fortran calling sequence for KSPConvergedDefaultCreate ? It is supposed to return a valid pointer and I don't succeed in doing so from Fortran.
If you have any idea, I'd greatly appreciate it
Thank you!
Natacha
PS I have attached my code (it's a slightly modified version of ex2f.F showing the convergence test code )
<ex2f.F>

[Natacha BEREUX]

Thanks a lot Barry : it works perfectly for me !
Best regards
Natacha

Post by Barry Smith
It will be very similar to usage from C. You should be able to do something like
PetscFortranAddress ctx
call KSPConvergedDefaultCreate(ctx,ierr)
call KSPMonitorSet(ksp,
MyKSPConverged,ctx,kspconvergeddefaultdestroy,ierr)
then in your MyKSPConverged pass the argument called "dummy" to the default monitor.
Barry

Post by Natacha BEREUX
Dear PETSc users,
I am using PETSc Fortran API.
I try to solve a linear system, and would like to define my own

convergence test.

Post by Natacha BEREUX
More precisely, my convergence test calls the default convergence test
subroutine MyKSPConverged(ksp,n,rnorm,flag,dummy,ierr)
implicit none
#include <petsc/finclude/petscsys.h>
#include <petsc/finclude/petscvec.h>
#include <petsc/finclude/petscksp.h>
KSP ksp
PetscErrorCode ierr
PetscInt n,dummy
KSPConvergedReason flag
PetscReal rnorm, true_rnorm
Vec true_res
!
call KSPConvergedDefault(ksp,n,rnorm,flag,PETSC_NULL_OBJECT,ierr)
!
! If convergence test succeeds
if ( (flag == KSP_CONVERGED_ATOL) .or. &
& (flag == KSP_CONVERGED_RTOL)) then
! Compute true residual
call KSPBuildResidual( ksp , PETSC_NULL_OBJECT, &
& PETSC_NULL_OBJECT, true_res, ierr )
! Compute true residual norm
call VecNorm(true_res,NORM_2,true_rnorm,ierr)
! And check again convergence with respect to the true residual

norm

Post by Natacha BEREUX
call KSPConvergedDefault(ksp,n,true_rnorm,flag, &
& PETSC_NULL_OBJECT, ierr)
! Free memory
call VecDestroy(true_res, ierr)
endif
!
ierr = 0
end
I get the following error message
[0]PETSC ERROR: --------------------- Error Message

--------------------------------------------------------------

Post by Natacha BEREUX
[0]PETSC ERROR: Null argument, when expecting valid pointer
[0]PETSC ERROR: Convergence context must have been created with

KSPConvergedDefaultCreate()

Post by Natacha BEREUX
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html

for trouble shooting.

Post by Natacha BEREUX
[0]PETSC ERROR: Petsc Release Version 3.6.2, Oct, 02, 2015
I understand that I should have call KSPConvergedDefaultCreate() before

calling KSConvergedDefault( ....)

Post by Natacha BEREUX
Am I right ?
If so what is the Fortran calling sequence for

KSPConvergedDefaultCreate ? It is supposed to return a valid pointer and I
don't succeed in doing so from Fortran.

Post by Natacha BEREUX
If you have any idea, I'd greatly appreciate it
Thank you!
Natacha
PS I have attached my code (it's a slightly modified version of ex2f.F

showing the convergence test code )

Post by Natacha BEREUX
<ex2f.F>