[petsc-users] PCFIELDSPLIT question
Hom Nath Gharti
hng.email at gmail.com
Tue Feb 9 09:57:51 CST 2016
Sounds interesting! Thanks a lot Matt! I will have a look.
Hom Nath
On Tue, Feb 9, 2016 at 10:36 AM, Matthew Knepley <knepley at gmail.com> wrote:
> On Tue, Feb 9, 2016 at 9:31 AM, Hom Nath Gharti <hng.email at gmail.com> wrote:
>>
>> Thanks a lot Matt!
>>
>> Were you referring to
>>
>> http://www.mcs.anl.gov/petsc/petsc-current/src/snes/examples/tutorials/ex62.c.html
>> ?
>>
>> I do not see any statements related to PCFieldSplit there. Am I
>> missing something here?
>
>
> Yes. The whole point is not to put anything specific to FIELDSPLIT in the
> code. It is all in options. For example,
>
> ./ex62 -run_type full -refinement_limit 0.00625 -bc_type dirichlet
> -interpolate 1 -vel_petscspace_order 2 -pres_petscspace_order 1 -ksp_type
> fgmres -ksp_gmres_restart 100 -ksp_rtol 1.0e-9 -pc_type fieldsplit
> -pc_fieldsplit_type schur -pc_fieldsplit_schur_factorization_type upper
> -fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_velocity_ksp_type gmres
> -fieldsplit_velocity_pc_type lu -fieldsplit_pressure_pc_type jacobi
> -snes_monitor_short -ksp_monitor_short -snes_converged_reason
> -ksp_converged_reason -snes_view -show_solution 0
>
> The reason that it works is that the DM calls PCFIeldSplitSetIS() for each
> field in the DM.
>
> Thanks,
>
> Matt
>
>>
>> Thanks,
>> Hom Nath
>>
>> On Tue, Feb 9, 2016 at 10:19 AM, Matthew Knepley <knepley at gmail.com>
>> wrote:
>> > On Tue, Feb 9, 2016 at 9:10 AM, Hom Nath Gharti <hng.email at gmail.com>
>> > wrote:
>> >>
>> >> Thank you so much Barry!
>> >>
>> >> For my small test case, with -pc_fieldsplit_block_size 4, the program
>> >> runs, although the answer was not correct. At least now I get
>> >> something to look upon. I am using PCFieldSplitSetIS to set the
>> >> fields. Do I still need to use -pc_fieldsplit_block_size?
>> >
>> >
>> > No, this is only for co-located discretizations.
>> >
>> >>
>> >> In my case each grid point may have different variable sets. For
>> >> example, the grid point in the solid region has displacement and
>> >> gravity potential: ux, uy, uz, and \phi. Whereas the grid point in the
>> >> fluid region has scalar potential, pressure and gravity potential:
>> >> \chi, p, and \phi. And the solid-fluid interface has all of them. Do
>> >> you think I can still use PCFIELDSPLIT in this situation?
>> >
>> >
>> > We have examples, like SNES ex62, which do exactly this.
>> >
>> > Thanks,
>> >
>> > Matt
>> >
>> >>
>> >> Best,
>> >> Hom Nath
>> >>
>> >>
>> >>
>> >> On Mon, Feb 8, 2016 at 2:27 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>> >> >
>> >> >
>> >> > In this case you need to provide two pieces of information to the
>> >> > PCFIELDSPLIT. What we call the "block size" or bs which is the number
>> >> > of
>> >> > "basic fields" in the problem. For example if at each grid point you
>> >> > have
>> >> > x-velocity, y-velocity, and pressure the block size is 3. The second
>> >> > is you
>> >> > need to tell PCFIELDSPLIT what "basic fields" are in each split you
>> >> > want to
>> >> > use.
>> >> >
>> >> > In your case you can do this with -pc_fieldsplit_block_size 4.
>> >> > (Note if you use a DM to define your problem the PCFIELDSPLIT will
>> >> > automatically get the bs from the DM so you do not need to provide
>> >> > it.
>> >> > Similarly if you set a block size on your Mat the PCFIELDSPLIT will
>> >> > use that
>> >> > so you don't need to set it).
>> >> >
>> >> > Then use -pc_fieldsplit_0_fields 0,1 to indicate your first split
>> >> > is
>> >> > the 0 and 1 basic fields and -pc_fieldsplit_1_fields 2,3 to indicate
>> >> > the
>> >> > second split is the 2 and 3 basic fields.
>> >> > (By default if you do not provide this then PCFIELDSPLIT will use bs
>> >> > splits (4 in your case) one for each basic field.
>> >> >
>> >> > Barry
>> >> >
>> >> >> On Feb 8, 2016, at 11:20 AM, Hom Nath Gharti <hng.email at gmail.com>
>> >> >> wrote:
>> >> >>
>> >> >> Hi Matt, Hi all,
>> >> >>
>> >> >> I am trying to have some feel for PCFIELDSPLIT testing on a very
>> >> >> small
>> >> >> matrix (attached below). I have 4 degrees of freedoms. I use 4
>> >> >> processors. I want to split 4 dofs into two fields each having two
>> >> >> dofs. I don't know whether this my be a problem for petsc. When I
>> >> >> use
>> >> >> the command:
>> >> >> srun -n 4 ./xtestfs -ksp_monitor -ksp_view
>> >> >>
>> >> >> It runs fine.
>> >> >>
>> >> >> But when I want to use field split options using the command:
>> >> >> srun -n 4 ./xtestfs -ksp_monitor -ksp_type fgmres -pc_type
>> >> >> fieldsplit
>> >> >> -fieldsplit_0_ksp_type gmres -fieldsplit_0_pc_type bjacobi
>> >> >> -fieldsplit_1_pc_type jacobi
>> >> >>
>> >> >> I get the following error message:
>> >> >> [0]PETSC ERROR: Petsc has generated inconsistent data
>> >> >> [0]PETSC ERROR: Unhandled case, must have at least two fields, not 1
>> >> >> [0]PETSC ERROR: See
>> >> >> http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble
>> >> >> shooting.
>> >> >> [0]PETSC ERROR: Petsc Release Version 3.6.3, Dec, 03, 2015
>> >> >> [0]PETSC ERROR: /tigress/hgharti/test/testfs/./xtestfs on a
>> >> >> arch-linux2-c-debug named tiger-r11n1 by hgharti Mon Feb 8 11:40:03
>> >> >> 2016
>> >> >> [0]PETSC ERROR: Configure options
>> >> >>
>> >> >>
>> >> >> --with-blas-lapack-dir=/opt/intel/composer_xe_2015.2.164/mkl/lib/intel64/
>> >> >> --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90
>> >> >> --with-mpiexec=mpiexec --with-debugging=1 --download-scalapack
>> >> >> --download-mumps --download-pastix --download-superlu
>> >> >> --download-superlu_dist --download-metis --download-parmetis
>> >> >> --download-ptscotch --download-hypre
>> >> >> [0]PETSC ERROR: #1 PCFieldSplitSetDefaults() line 469 in
>> >> >>
>> >> >>
>> >> >> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/pc/impls/fieldsplit/fieldsplit.c
>> >> >> [0]PETSC ERROR: #2 PCSetUp_FieldSplit() line 486 in
>> >> >>
>> >> >>
>> >> >> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/pc/impls/fieldsplit/fieldsplit.c
>> >> >> [0]PETSC ERROR: #3 PCSetUp() line 983 in
>> >> >>
>> >> >>
>> >> >> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/pc/interface/precon.c
>> >> >> [0]PETSC ERROR: #4 KSPSetUp() line 332 in
>> >> >>
>> >> >>
>> >> >> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/ksp/interface/itfunc.c
>> >> >> [0]PETSC ERROR: #5 KSPSolve() line 546 in
>> >> >>
>> >> >>
>> >> >> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/ksp/interface/itfunc.c
>> >> >> WARNING! There are options you set that were not used!
>> >> >> WARNING! could be spelling mistake, etc!
>> >> >> Option left: name:-fieldsplit_0_ksp_type value: gmres
>> >> >> Option left: name:-fieldsplit_0_pc_type value: bjacobi
>> >> >> Option left: name:-fieldsplit_1_pc_type value: jacobi
>> >> >> forrtl: error (76): Abort trap signal
>> >> >>
>> >> >> I tried several trials but could not fix the problem. Is it the
>> >> >> FORTRAN problem or am I doing something wrong? Any suggestions would
>> >> >> be greatly appreciated.
>> >> >> For your information I use:
>> >> >> PETSc-3.6.3
>> >> >> intel-16.0 compiler
>> >> >> intel-mpi-5.1.1
>> >> >>
>> >> >> Program
>> >> >>
>> >> >>
>> >> >> Best,
>> >> >> Hom Nath
>> >> >>
>> >> >> ! simple test case for PCFIELDSPLIT
>> >> >> !
>> >> >>
>> >> >> -----------------------------------------------------------------------
>> >> >> program testfs
>> >> >> implicit none
>> >> >> #include "petsc/finclude/petscsys.h"
>> >> >> #include "petsc/finclude/petscvec.h"
>> >> >> #include "petsc/finclude/petscvec.h90"
>> >> >> #include "petsc/finclude/petscmat.h"
>> >> >> #include "petsc/finclude/petscksp.h"
>> >> >> #include "petsc/finclude/petscpc.h"
>> >> >> #include "petsc/finclude/petscviewer.h"
>> >> >> #include "petsc/finclude/petscviewer.h90"
>> >> >>
>> >> >> Vec x,b,u
>> >> >> Mat A
>> >> >> KSP ksp
>> >> >> PC pc
>> >> >> PetscErrorCode ierr
>> >> >> PetscBool flg
>> >> >> PetscInt errcode,its,maxitr,myrank,nproc
>> >> >> PetscInt nedof,nelmt,ndof,nenod,ngdof,fixdof,nsparse,neq
>> >> >> PetscInt,allocatable :: krow_sparse(:),ggdof_elmt(:,:), &
>> >> >> inode_elmt(:,:)
>> >> >>
>> >> >> PetscReal,allocatable :: storef(:,:),storekmat(:,:,:)
>> >> >> PetscInt gdof0(2),gdof1(2)
>> >> >>
>> >> >> ! initialize MPI
>> >> >>
>> >> >> call MPI_INIT(errcode)
>> >> >> if(errcode /= 0)stop 'ERROR: cannot initialize MPI!'
>> >> >> call MPI_COMM_RANK(MPI_COMM_WORLD,myrank,errcode)
>> >> >> if(errcode /= 0)stop 'ERROR: cannot find processor ID'
>> >> >> call MPI_COMM_SIZE(MPI_COMM_WORLD,nproc,errcode)
>> >> >> if(errcode /= 0)stop 'ERROR: cannot find number of processors!'
>> >> >>
>> >> >> ! define some parameters
>> >> >> ! 1D model with 4 elements. Each elements consits of 2 nodes. Node 0
>> >> >> is
>> >> >> fixed.
>> >> >> ! 1-----------2-----------3-----------4-----------5
>> >> >> nelmt=1 ! per processor
>> >> >> nenod=2 ! number of nodes per element
>> >> >> nedof=2 ! number of DOFs per element
>> >> >> ndof=2 ! number of DOFs
>> >> >> ngdof=4 ! total number of global DOFs
>> >> >> fixdof=1
>> >> >>
>> >> >> if(myrank==0)then
>> >> >> neq=1 ! number of equations
>> >> >> nsparse=1
>> >> >> else
>> >> >> neq=2 ! number of equations
>> >> >> nsparse=4
>> >> >> endif
>> >> >>
>> >> >> allocate(storef(nedof,nelmt),storekmat(nedof,nedof,nelmt),
>> >> >> &
>> >> >>
>> >> >> ggdof_elmt(nedof,nelmt),inode_elmt(nenod,nelmt),krow_sparse(nsparse))
>> >> >>
>> >> >> storef=0.0_8 ! local RHS vector
>> >> >> storekmat=0.0_8 ! local stiffness matrix
>> >> >> if(myrank==0)then
>> >> >> krow_sparse(:)=1
>> >> >> storef(:,1)=(/12.5000_8, 12.5000_8/)
>> >> >> storekmat(:,:,1) = reshape((/1.2333333332_8, 0.0166666667_8, &
>> >> >> 0.0166666667_8,
>> >> >> 1.2333333332_8/),(/nedof,nedof/))
>> >> >> inode_elmt(:,1) = (/1,2/)
>> >> >> ggdof_elmt(:,1) = (/0,1/) ! 0 because left node is fixed
>> >> >> elseif(myrank==1)then
>> >> >> krow_sparse(:)=(/1,1,2,2/)
>> >> >> storef(:,1)=(/12.5000_8, 12.5000_8/)
>> >> >> storekmat(:,:,1) = reshape((/1.2333333332_8, 0.0166666667_8, &
>> >> >> 0.0166666667_8,
>> >> >> 1.2333333332_8/),(/nedof,nedof/))
>> >> >> inode_elmt(:,1) = (/1,2/)
>> >> >> ggdof_elmt(:,1) = (/1,2/)
>> >> >> elseif(myrank==2)then
>> >> >> krow_sparse(:)=(/1,1,2,2/)
>> >> >> storef(:,1)=(/12.5000_8, 12.5000_8/)
>> >> >> storekmat(:,:,1) = reshape((/1.2333333332_8, 0.0166666667_8, &
>> >> >> 0.0166666667_8,
>> >> >> 1.2333333332_8/),(/nedof,nedof/))
>> >> >> inode_elmt(:,1) = (/1,2/)
>> >> >> ggdof_elmt(:,1) = (/2,3/)
>> >> >> elseif(myrank==3)then
>> >> >> krow_sparse(:)=(/1,1,2,2/)
>> >> >> storef(:,1)=(/12.5000_8, 22.5000_8/)
>> >> >> storekmat(:,:,1) = reshape((/1.2333333332_8, 0.0166666667_8, &
>> >> >> 0.0166666667_8,
>> >> >> 1.2333333332_8/),(/nedof,nedof/))
>> >> >> inode_elmt(:,1) = (/1,2/)
>> >> >> ggdof_elmt(:,1) = (/3,4/)
>> >> >> endif
>> >> >>
>> >> >> call petsc_initialize
>> >> >> call petsc_set_matrix
>> >> >> call petsc_set_vector
>> >> >> call petsc_solve
>> >> >> call petsc_finalize
>> >> >>
>> >> >> ! deallocate
>> >> >> deallocate(storef,storekmat,ggdof_elmt,inode_elmt)
>> >> >> deallocate(krow_sparse)
>> >> >> contains
>> >> >>
>> >> >>
>> >> >> !-------------------------------------------------------------------------------
>> >> >> subroutine petsc_initialize()
>> >> >> implicit none
>> >> >> PetscInt :: istart,iend
>> >> >> PetscInt :: nzeros_max,nzeros_min
>> >> >> PetscReal :: atol,dtol,rtol
>> >> >> PetscInt,allocatable :: nzeros(:)
>> >> >> IS gdof0_is,gdof1_is
>> >> >>
>> >> >> call PetscInitialize(PETSC_NULL_CHARACTER,ierr)
>> >> >> call PetscOptionsGetInt(PETSC_NULL_CHARACTER,'-n',ngdof,flg,ierr)
>> >> >>
>> >> >> ! count number of nonzeros per row
>> >> >> allocate(nzeros(neq))
>> >> >> nzeros=0
>> >> >> nzeros(krow_sparse)=nzeros(krow_sparse)+1
>> >> >> nzeros_max=maxval(nzeros)
>> >> >> nzeros_min=minval(nzeros)
>> >> >>
>> >> >> ! create matrix
>> >> >> call MatCreate(PETSC_COMM_WORLD,A,ierr)
>> >> >> call MatSetType(A,MATMPIAIJ,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> call MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,ngdof,ngdof,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> ! preallocation
>> >> >> call
>> >> >>
>> >> >> MatMPIAIJSetPreallocation(A,nzeros_max,PETSC_NULL_INTEGER,nzeros_max, &
>> >> >> PETSC_NULL_INTEGER,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >>
>> >> >> call MatGetOwnershipRange(A,istart,iend,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> print*,'ownership:',myrank,istart,iend
>> >> >> ! create vector
>> >> >> call VecCreate(PETSC_COMM_WORLD,x,ierr)
>> >> >> call VecSetSizes(x,PETSC_DECIDE,ngdof,ierr)
>> >> >> call VecSetType(x,VECMPI,ierr)
>> >> >> call VecDuplicate(x,b,ierr)
>> >> >> call VecDuplicate(x,u,ierr)
>> >> >>
>> >> >>
>> >> >>
>> >> >> !*******************************************************************************
>> >> >> ! get IS for split fields
>> >> >> gdof0=(/0,1/)
>> >> >> gdof1=(/2,3/)
>> >> >> call
>> >> >>
>> >> >> ISCreateGeneral(PETSC_COMM_WORLD,2,gdof0,PETSC_COPY_VALUES,gdof0_is,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> call
>> >> >>
>> >> >> ISCreateGeneral(PETSC_COMM_WORLD,2,gdof1,PETSC_COPY_VALUES,gdof1_is,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >>
>> >> >>
>> >> >> !*******************************************************************************
>> >> >>
>> >> >> ! Create linear solver context
>> >> >> call KSPCreate(PETSC_COMM_WORLD,ksp,ierr)
>> >> >> call KSPSetOperators(ksp,A,A,ierr)
>> >> >>
>> >> >> call KSPGetPC(ksp,pc,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >>
>> >> >>
>> >> >>
>> >> >> !*******************************************************************************
>> >> >> ! split PC
>> >> >> call PCFieldSplitSetIS(pc,"0",gdof0_is,ierr);
>> >> >> CHKERRQ(ierr)
>> >> >> call ISDestroy(gdof0_is,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> call PCFieldSplitSetIS(pc,"1",gdof1_is,ierr);
>> >> >> CHKERRQ(ierr)
>> >> >> call ISDestroy(gdof1_is,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >>
>> >> >>
>> >> >> !*******************************************************************************
>> >> >>
>> >> >> rtol = 1.0d-6
>> >> >> atol = 1.0d-6
>> >> >> dtol = 1.0d10
>> >> >> maxitr = 1000
>> >> >> call KSPSetTolerances(ksp,rtol,atol,dtol,maxitr,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> call KSPSetFromOptions(ksp,ierr)
>> >> >> end subroutine petsc_initialize
>> >> >>
>> >> >>
>> >> >> !-------------------------------------------------------------------------------
>> >> >>
>> >> >> subroutine petsc_set_matrix()
>> >> >>
>> >> >> implicit none
>> >> >> integer :: i,i_elmt,j,ncount
>> >> >> integer :: ggdof(NEDOF),idof(NEDOF),igdof(NEDOF)
>> >> >>
>> >> >> ! Set and assemble matrix.
>> >> >> call MatZeroEntries(A,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> do i_elmt=1,nelmt
>> >> >> ggdof(:)=ggdof_elmt(:,i_elmt)
>> >> >> ggdof(:)=ggdof(:)-1 ! petsc index starts from 0
>> >> >> ncount=0; idof=-1; igdof=-1
>> >> >> do i=1,NEDOF
>> >> >> do j=1,NEDOF
>> >> >> if(ggdof(i).ge.0.and.ggdof(j).ge.0)then
>> >> >> call
>> >> >> MatSetValues(A,1,ggdof(i),1,ggdof(j),storekmat(i,j,i_elmt),
>> >> >> &
>> >> >> ADD_VALUES,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> endif
>> >> >> enddo
>> >> >> enddo
>> >> >> enddo
>> >> >> call MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY,ierr)
>> >> >> call MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY,ierr)
>> >> >> if(myrank==0)print*,'matrix setting & assembly complete!'
>> >> >>
>> >> >> end subroutine petsc_set_matrix
>> >> >>
>> >> >>
>> >> >> !-------------------------------------------------------------------------------
>> >> >>
>> >> >> subroutine petsc_set_vector()
>> >> >> implicit none
>> >> >> PetscScalar zero
>> >> >> integer :: i,i_elmt,ncount
>> >> >> integer :: ggdof(NEDOF),idof(NEDOF),igdof(NEDOF)
>> >> >>
>> >> >> ! set vector
>> >> >> zero=0.0_8
>> >> >> call VecSet(b,zero,ierr)
>> >> >> do i_elmt=1,nelmt
>> >> >> ggdof(:)=ggdof_elmt(:,i_elmt)
>> >> >> ggdof(:)=ggdof(:)-1 ! petsc index starts from 0
>> >> >> ncount=0; idof=-1; igdof=-1
>> >> >> do i=1,NEDOF
>> >> >> if(ggdof(i).ge.0)then
>> >> >> call
>> >> >> VecSetValues(b,1,ggdof(i),storef(i,i_elmt),ADD_VALUES,ierr);
>> >> >> CHKERRQ(ierr)
>> >> >> endif
>> >> >> enddo
>> >> >> enddo
>> >> >>
>> >> >> ! assemble vector
>> >> >> call VecAssemblyBegin(b,ierr)
>> >> >> call VecAssemblyEnd(b,ierr)
>> >> >> if(myrank==0)print*,'vector setting & assembly complete!'
>> >> >>
>> >> >> end subroutine petsc_set_vector
>> >> >>
>> >> >>
>> >> >> !-------------------------------------------------------------------------------
>> >> >>
>> >> >> subroutine petsc_solve()
>> >> >> implicit none
>> >> >> PetscInt ireason
>> >> >> PetscScalar a_v(1)
>> >> >> PetscOffset a_i
>> >> >> PetscInt n
>> >> >> PetscReal,allocatable :: sdata(:)
>> >> >>
>> >> >> call VecGetSize(b,n,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> allocate(sdata(n))
>> >> >> sdata=0.0_8
>> >> >> call VecGetArray(b,a_v,a_i,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> sdata(1:n)=a_v(a_i+1:a_i+n)
>> >> >> call VecRestoreArray(b,a_v,a_i,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> print*,'rhs:',sdata
>> >> >>
>> >> >> call KSPSolve(ksp,b,x,ierr)
>> >> >> sdata=0.0_8
>> >> >> call VecGetArray(x,a_v,a_i,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> sdata(1:n)=a_v(a_i+1:a_i+n)
>> >> >> call VecRestoreArray(b,a_v,a_i,ierr)
>> >> >> CHKERRQ(ierr)
>> >> >> print*,'solution:',sdata
>> >> >>
>> >> >> ! Check convergence
>> >> >> call KSPGetConvergedReason(ksp,ireason,ierr)
>> >> >> if(myrank==0)print*,'converges reason',myrank,ireason
>> >> >> call KSPGetIterationNumber(ksp,its,ierr)
>> >> >> if(myrank==0)print*,'Iterations:',its
>> >> >> deallocate(sdata)
>> >> >> end subroutine petsc_solve
>> >> >>
>> >> >>
>> >> >> !-------------------------------------------------------------------------------
>> >> >>
>> >> >> subroutine petsc_finalize()
>> >> >> implicit none
>> >> >>
>> >> >> ! Free work space.
>> >> >> call VecDestroy(x,ierr)
>> >> >> call VecDestroy(u,ierr)
>> >> >> call VecDestroy(b,ierr)
>> >> >> call MatDestroy(A,ierr)
>> >> >> call KSPDestroy(ksp,ierr)
>> >> >> call PetscFinalize(ierr)
>> >> >> CHKERRQ(ierr)
>> >> >>
>> >> >> end subroutine petsc_finalize
>> >> >>
>> >> >>
>> >> >> !-------------------------------------------------------------------------------
>> >> >>
>> >> >> end program testfs
>> >> >>
>> >> >> On Tue, Feb 2, 2016 at 4:54 PM, Matthew Knepley <knepley at gmail.com>
>> >> >> wrote:
>> >> >>> On Tue, Feb 2, 2016 at 3:11 PM, Hom Nath Gharti
>> >> >>> <hng.email at gmail.com>
>> >> >>> wrote:
>> >> >>>>
>> >> >>>> Thanks a lot. I will try.
>> >> >>>
>> >> >>>
>> >> >>> Also, if you send a small test case, we can run it and tell you the
>> >> >>> problem.
>> >> >>>
>> >> >>> Matt
>> >> >>>
>> >> >>>>
>> >> >>>> Hom Nath
>> >> >>>>
>> >> >>>> On Tue, Feb 2, 2016 at 4:02 PM, Matthew Knepley
>> >> >>>> <knepley at gmail.com>
>> >> >>>> wrote:
>> >> >>>>> On Tue, Feb 2, 2016 at 3:01 PM, Hom Nath Gharti
>> >> >>>>> <hng.email at gmail.com>
>> >> >>>>> wrote:
>> >> >>>>>>
>> >> >>>>>> Thanks again Matt. Unfortunately got the same errors with '0'. I
>> >> >>>>>> think
>> >> >>>>>> both are valid in Fortran.
>> >> >>>>>
>> >> >>>>>
>> >> >>>>> Then you will have to go in the debugger and see why its not
>> >> >>>>> creating 4
>> >> >>>>> splits, since this is exactly
>> >> >>>>> what it does in our tests. This is how all the SNES tests that I
>> >> >>>>> use
>> >> >>>>> work. I
>> >> >>>>> am sure its a Fortran
>> >> >>>>> problem.
>> >> >>>>>
>> >> >>>>> Thanks,
>> >> >>>>>
>> >> >>>>> Matt
>> >> >>>>>
>> >> >>>>>>
>> >> >>>>>> Hom Nath
>> >> >>>>>>
>> >> >>>>>> On Tue, Feb 2, 2016 at 3:42 PM, Matthew Knepley
>> >> >>>>>> <knepley at gmail.com>
>> >> >>>>>> wrote:
>> >> >>>>>>> On Tue, Feb 2, 2016 at 2:35 PM, Hom Nath Gharti
>> >> >>>>>>> <hng.email at gmail.com>
>> >> >>>>>>> wrote:
>> >> >>>>>>>>
>> >> >>>>>>>> Thank you so much Matt.
>> >> >>>>>>>>
>> >> >>>>>>>> I now tried the following:
>> >> >>>>>>>>
>> >> >>>>>>>> ======================================================
>> >> >>>>>>>> call KSPCreate(PETSC_COMM_WORLD,ksp,ierr)
>> >> >>>>>>>> call KSPGetPC(ksp,pc,ierr)
>> >> >>>>>>>>
>> >> >>>>>>>> call PCFieldSplitSetIS(pc,"0",gdofu_is,ierr);
>> >> >>>>>>>> call ISDestroy(gdofu_is,ierr)
>> >> >>>>>>>> call PCFieldSplitSetIS(pc,"1",gdofchi_is,ierr);
>> >> >>>>>>>> call ISDestroy(gdofchi_is,ierr)
>> >> >>>>>>>> call PCFieldSplitSetIS(pc,"2",gdofp_is,ierr);
>> >> >>>>>>>> call ISDestroy(gdofp_is,ierr)
>> >> >>>>>>>> call PCFieldSplitSetIS(pc,"3",gdofphi_is,ierr);
>> >> >>>>>>>> call ISDestroy(gdofphi_is,ierr)
>> >> >>>>>>>>
>> >> >>>>>>>> ! Amat changes in each time steps
>> >> >>>>>>>> call KSPSetOperators(ksp,Amat,Amat,ierr) !version >= 3.5.0
>> >> >>>>>>>>
>> >> >>>>>>>> call KSPSolve(ksp,bvec,xvec,ierr)
>> >> >>>>>>>> ======================================================
>> >> >>>>>>>
>> >> >>>>>>>
>> >> >>>>>>> I am guessing that "0" is not a valid string for your Fortran
>> >> >>>>>>> compiler.
>> >> >>>>>>> Are
>> >> >>>>>>> you sure
>> >> >>>>>>> its not single quotes '0'?
>> >> >>>>>>>
>> >> >>>>>>> Matt
>> >> >>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>> But I get the following error:
>> >> >>>>>>>>
>> >> >>>>>>>> [0]PETSC ERROR: --------------------- Error Message
>> >> >>>>>>>> --------------------------------------------------------------
>> >> >>>>>>>> [0]PETSC ERROR: Petsc has generated inconsistent data
>> >> >>>>>>>> [0]PETSC ERROR: Unhandled case, must have at least two fields,
>> >> >>>>>>>> not 1
>> >> >>>>>>>> [0]PETSC ERROR: See
>> >> >>>>>>>> http://www.mcs.anl.gov/petsc/documentation/faq.html for
>> >> >>>>>>>> trouble
>> >> >>>>>>>> shooting.
>> >> >>>>>>>> [0]PETSC ERROR: Petsc Release Version 3.6.3, Dec, 03, 2015
>> >> >>>>>>>> [0]PETSC ERROR:
>> >> >>>>>>>> /tigress/hgharti/gitwork/SPECFEM3D_GLOBEVSPP/./bin/xspecfem3D
>> >> >>>>>>>> on
>> >> >>>>>>>> a
>> >> >>>>>>>> arch-linux2-c-debug named tiger-r3c1n7 by hgharti Tue Feb 2
>> >> >>>>>>>> 15:
>> >> >>>>>>>> 29:30 2016
>> >> >>>>>>>> [0]PETSC ERROR: Configure options
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>> --with-blas-lapack-dir=/opt/intel/composer_xe_2015.2.164/mkl/lib/intel64/
>> >> >>>>>>>> --with-cc=mpicc --with-cxx=mpicxx --wit
>> >> >>>>>>>> h-fc=mpif90 --with-mpiexec=mpiexec --with-debugging=1
>> >> >>>>>>>> --download-scalapack --download-mumps --download-pastix
>> >> >>>>>>>> --download-superlu --download-superlu_dist --download-metis
>> >> >>>>>>>> --download-parmetis --download-ptscotch --download-hypre
>> >> >>>>>>>> [0]PETSC ERROR: #1 PCFieldSplitSetDefaults() line 469 in
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/pc/impls/fieldsplit/fieldsplit.c
>> >> >>>>>>>> [0]PETSC ERROR: #2 PCSetUp_FieldSplit() line 486 in
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/pc/impls/fieldsplit/fieldsplit.c
>> >> >>>>>>>> [0]PETSC ERROR: #3 PCSetUp() line 983 in
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/pc/interface/precon.c
>> >> >>>>>>>> [0]PETSC ERROR: #4 KSPSetUp() line 332 in
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/ksp/interface/itfunc.c
>> >> >>>>>>>> [0]PETSC ERROR: #5 KSPSolve() line 546 in
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>>
>> >> >>>>>>>> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/ksp/interface/itfunc.c
>> >> >>>>>>>> forrtl: error (76): Abort trap signal
>> >> >>>>>>>>
>> >> >>>>>>>> Am I missing something?
>> >> >>>>>>>>
>> >> >>>>>>>> Thanks,
>> >> >>>>>>>> Hom Nath
>> >> >>>>>>>>
>> >> >>>>>>>> On Tue, Feb 2, 2016 at 3:24 PM, Matthew Knepley
>> >> >>>>>>>> <knepley at gmail.com>
>> >> >>>>>>>> wrote:
>> >> >>>>>>>>> On Tue, Feb 2, 2016 at 2:20 PM, Hom Nath Gharti
>> >> >>>>>>>>> <hng.email at gmail.com>
>> >> >>>>>>>>> wrote:
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> Hi Matt, hi all,
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> I am trying to use PCFIELDSPLIT for my solver which consists
>> >> >>>>>>>>>> of
>> >> >>>>>>>>>> 4
>> >> >>>>>>>>>> different variables, namely, u (displacement vector), \chi
>> >> >>>>>>>>>> (displacement potential), p(pressure), and \phi (gravity
>> >> >>>>>>>>>> potential).
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> My code segment looks like the following:
>> >> >>>>>>>>>> ======================================================
>> >> >>>>>>>>>> call KSPCreate(PETSC_COMM_WORLD,ksp,ierr)
>> >> >>>>>>>>>> call KSPGetPC(ksp,pc,ierr)
>> >> >>>>>>>>>> nsplit=4
>> >> >>>>>>>>>> call PCFieldSplitSetBlockSize(pc,nsplit,ierr);
>> >> >>>>>>>>>
>> >> >>>>>>>>>
>> >> >>>>>>>>> You do not need the statement above.
>> >> >>>>>>>>>
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> call PCFieldSplitSetIS(pc,"0",gdofu_is,ierr);
>> >> >>>>>>>>>> call ISDestroy(gdofu_is,ierr)
>> >> >>>>>>>>>> call PCFieldSplitSetIS(pc,"1",gdofchi_is,ierr);
>> >> >>>>>>>>>> call ISDestroy(gdofchi_is,ierr)
>> >> >>>>>>>>>> call PCFieldSplitSetIS(pc,"2",gdofp_is,ierr);
>> >> >>>>>>>>>> call ISDestroy(gdofp_is,ierr)
>> >> >>>>>>>>>> call PCFieldSplitSetIS(pc,"3",gdofphi_is,ierr);
>> >> >>>>>>>>>> call ISDestroy(gdofphi_is,ierr)
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> call PCFieldSplitGetSubKSP(pc,nsplit,subksp,ierr);
>> >> >>>>>>>>>
>> >> >>>>>>>>>
>> >> >>>>>>>>> These SetOperators() calls are wrong. I am not sure why you
>> >> >>>>>>>>> want
>> >> >>>>>>>>> them
>> >> >>>>>>>>> here.
>> >> >>>>>>>>> Also, that means you do not need the call above.
>> >> >>>>>>>>>
>> >> >>>>>>>>> Thanks,
>> >> >>>>>>>>>
>> >> >>>>>>>>> Matt
>> >> >>>>>>>>>
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> call KSPSetOperators(subksp(1),Amat,Amat,ierr);
>> >> >>>>>>>>>> call KSPSetOperators(subksp(2),Amat,Amat,ierr);
>> >> >>>>>>>>>> call KSPSetOperators(subksp(3),Amat,Amat,ierr);
>> >> >>>>>>>>>> call KSPSetOperators(subksp(4),Amat,Amat,ierr);
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> call KSPSolve(ksp,bvec,xvec,ierr)
>> >> >>>>>>>>>> ======================================================
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> But I am getting the following error:
>> >> >>>>>>>>>> [79]PETSC ERROR: Null argument, when expecting valid pointer
>> >> >>>>>>>>>> [79]PETSC ERROR: Null Object: Parameter # 1
>> >> >>>>>>>>>> [79]PETSC ERROR: #1 KSPSetOperators() line 536 in
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> /home/hgharti/lsoft/petsc-3.6.3-intel16-mpi5/src/ksp/ksp/interf
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> It looks like I am doing something wrong in "call
>> >> >>>>>>>>>> KSPSetOperators"
>> >> >>>>>>>>>> but
>> >> >>>>>>>>>> I could not figure that out.
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> Could anybody help me to fix this problem? I looked into
>> >> >>>>>>>>>> almost
>> >> >>>>>>>>>> all
>> >> >>>>>>>>>> related examples but I could not really figure out the
>> >> >>>>>>>>>> correct
>> >> >>>>>>>>>> steps
>> >> >>>>>>>>>> after "call PCFieldSplitSetIS".
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> Any help will be greatly appreciated.
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> Best,
>> >> >>>>>>>>>> Hom nath
>> >> >>>>>>>>>>
>> >> >>>>>>>>>> On Sun, Jan 24, 2016 at 7:14 PM, Hom Nath Gharti
>> >> >>>>>>>>>> <hng.email at gmail.com>
>> >> >>>>>>>>>> wrote:
>> >> >>>>>>>>>>> Thank you so much Matt! I will try.
>> >> >>>>>>>>>>>
>> >> >>>>>>>>>>> Hom Nath
>> >> >>>>>>>>>>>
>> >> >>>>>>>>>>> On Sun, Jan 24, 2016 at 6:26 AM, Matthew Knepley
>> >> >>>>>>>>>>> <knepley at gmail.com>
>> >> >>>>>>>>>>> wrote:
>> >> >>>>>>>>>>>> On Fri, Jan 22, 2016 at 2:19 PM, Hom Nath Gharti
>> >> >>>>>>>>>>>> <hng.email at gmail.com>
>> >> >>>>>>>>>>>> wrote:
>> >> >>>>>>>>>>>>>
>> >> >>>>>>>>>>>>> Dear all,
>> >> >>>>>>>>>>>>>
>> >> >>>>>>>>>>>>> I am new to PcFieldSplit.
>> >> >>>>>>>>>>>>>
>> >> >>>>>>>>>>>>> I have a matrix formed using MATMPIAIJ. Is it possible to
>> >> >>>>>>>>>>>>> use
>> >> >>>>>>>>>>>>> PCFIELDSPLIT operations in this type of matrix? Or does
>> >> >>>>>>>>>>>>> it
>> >> >>>>>>>>>>>>> have
>> >> >>>>>>>>>>>>> to
>> >> >>>>>>>>>>>>> be
>> >> >>>>>>>>>>>>> MATMPIBIJ or MATNEST format?
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>> Yes, you can split AIJ.
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>>
>> >> >>>>>>>>>>>>> If possible for MATMPIAIJ, could anybody provide me a
>> >> >>>>>>>>>>>>> simple
>> >> >>>>>>>>>>>>> example
>> >> >>>>>>>>>>>>> or few steps? Variables in the equations are displacement
>> >> >>>>>>>>>>>>> vector,
>> >> >>>>>>>>>>>>> scalar potential and pressure.
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>> If you do not have a collocated discretization, then you
>> >> >>>>>>>>>>>> have
>> >> >>>>>>>>>>>> to
>> >> >>>>>>>>>>>> use
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>> http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/PC/PCFieldSplitSetIS.html
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>> Thanks,
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>> Matt
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>>
>> >> >>>>>>>>>>>>> Thanks for help.
>> >> >>>>>>>>>>>>>
>> >> >>>>>>>>>>>>> Hom Nath
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>>
>> >> >>>>>>>>>>>> --
>> >> >>>>>>>>>>>> What most experimenters take for granted before they begin
>> >> >>>>>>>>>>>> their
>> >> >>>>>>>>>>>> experiments
>> >> >>>>>>>>>>>> is infinitely more interesting than any results to which
>> >> >>>>>>>>>>>> their
>> >> >>>>>>>>>>>> experiments
>> >> >>>>>>>>>>>> lead.
>> >> >>>>>>>>>>>> -- Norbert Wiener
>> >> >>>>>>>>>
>> >> >>>>>>>>>
>> >> >>>>>>>>>
>> >> >>>>>>>>>
>> >> >>>>>>>>> --
>> >> >>>>>>>>> What most experimenters take for granted before they begin
>> >> >>>>>>>>> their
>> >> >>>>>>>>> experiments
>> >> >>>>>>>>> is infinitely more interesting than any results to which
>> >> >>>>>>>>> their
>> >> >>>>>>>>> experiments
>> >> >>>>>>>>> lead.
>> >> >>>>>>>>> -- Norbert Wiener
>> >> >>>>>>>
>> >> >>>>>>>
>> >> >>>>>>>
>> >> >>>>>>>
>> >> >>>>>>> --
>> >> >>>>>>> What most experimenters take for granted before they begin
>> >> >>>>>>> their
>> >> >>>>>>> experiments
>> >> >>>>>>> is infinitely more interesting than any results to which their
>> >> >>>>>>> experiments
>> >> >>>>>>> lead.
>> >> >>>>>>> -- Norbert Wiener
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>>
>> >> >>>>> --
>> >> >>>>> What most experimenters take for granted before they begin their
>> >> >>>>> experiments
>> >> >>>>> is infinitely more interesting than any results to which their
>> >> >>>>> experiments
>> >> >>>>> lead.
>> >> >>>>> -- Norbert Wiener
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> --
>> >> >>> What most experimenters take for granted before they begin their
>> >> >>> experiments
>> >> >>> is infinitely more interesting than any results to which their
>> >> >>> experiments
>> >> >>> lead.
>> >> >>> -- Norbert Wiener
>> >> >
>> >
>> >
>> >
>> >
>> > --
>> > What most experimenters take for granted before they begin their
>> > experiments
>> > is infinitely more interesting than any results to which their
>> > experiments
>> > lead.
>> > -- Norbert Wiener
>
>
>
>
> --
> What most experimenters take for granted before they begin their experiments
> is infinitely more interesting than any results to which their experiments
> lead.
> -- Norbert Wiener
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