[petsc-users] error in calling VecGetArrayf90()
Ethan Coon
ecoon at lanl.gov
Wed Jan 5 10:45:21 CST 2011
On Tue, 2011-01-04 at 22:49 -0600, Satish Balay wrote:
> The global index starts at Istart - but the array index starts at 1 [for fortran array]
>
What Satish said. But you can get around this by declaring the
size/shape (by passing into a subroutine).
See
http://www.mcs.anl.gov/petsc/petsc-as/snapshots/petsc-current/src/snes/examples/tutorials/ex5f90.F.html
lines 113-121 and the subroutine FormFunctionLocal included therein for
an example.
Ethan
> Satish
>
> On Tue, 4 Jan 2011, Peter Wang wrote:
>
> >
> > In last question, the pointer xx_v is local data. However, if write them to the monitor or assign them to another array, the value is incorrect.
> >
> > The protion of the code to display them on the monitor is like as following:
> > call MatGetOwnershipRange(A,Istart,Iend,ierr)
> > call VecGetArrayF90(x,xx_v,ierr) ! Vector x is matched with Matrix A in the same communicator
> >
> > write(*,*)xx_v,myid ! write the poiner array together
> >
> > do i=Istart,Iend-1
> > write(6,*)'check xx_v',i,xx_v(i),myid !write the element of the array one by one with local range (Istart to Iend-1)
> > enddo
> >
> >
> > =========The result is as following: ( the values of the elements from 7 to 20 are not correct !!)
> >
> > 3999.9999999999982 3999.9999999999982 3999.9999999999982 3999.9999999999982 3999.9999999999982 3000.0000000000005 3000.0000000000005 0
> >
> > 3000.0000000000009 3000.0000000000009 3000.0000000000009 2000.0000000000011 2000.0000000000011 2000.0000000000000 1
> >
> > 2000.0000000000009 2000.0000000000009 1000.0000000000003 1000.0000000000003 1000.0000000000003 999.99999999999989 2
> >
> > 1000.0000000000000 0.0000000000000000 0.0000000000000000 0.0000000000000000 0.0000000000000000 0.0000000000000000 3
> >
> >
> > check xx_v 0 0.0000000000000000 0.0000000000000000 0
> > check xx_v 1 3999.9999999999982 3999.9999999999982 0
> > check xx_v 2 3999.9999999999982 3999.9999999999982 0
> > check xx_v 3 3999.9999999999982 3999.9999999999982 0
> > check xx_v 4 3999.9999999999982 3999.9999999999982 0
> > check xx_v 5 3999.9999999999982 3999.9999999999982 0
> > check xx_v 6 3000.0000000000005 3000.0000000000005 0
> > check xx_v 7 1.99665037664579820E-314 1.99665037664579820E-314 1
> > check xx_v 8 2.61360726650019422E-321 2.61360726650019422E-321 1
> > check xx_v 9 7.90505033345994471E-323 7.90505033345994471E-323 1
> > check xx_v 10 1.69759663277221785E-312 1.69759663277221785E-312 1
> > check xx_v 11 6.16846344148335980E-317 6.16846344148335980E-317 1
> > check xx_v 12 6.16846640587723485E-317 6.16846640587723485E-317 1
> > check xx_v 13 6.16838982570212945E-317 6.16838982570212945E-317 2
> > check xx_v 14 1.99665037664579820E-314 1.99665037664579820E-314 2
> > check xx_v 15 6.19790333112210216E-317 6.19790333112210216E-317 2
> > check xx_v 16 6.20255545324334334E-317 6.20255545324334334E-317 2
> > check xx_v 17 6.20225061473985929E-317 6.20225061473985929E-317 2
> > check xx_v 18 6.18242376037225006E-317 6.18242376037225006E-317 2
> > check xx_v 19 6.16846640587723485E-317 6.16846640587723485E-317 3
> > check xx_v 20 6.18113523716789609E-317 6.18113523716789609E-317 3
> > check xx_v 21 0.0000000000000000 0.0000000000000000 3
> > check xx_v 22 0.0000000000000000 0.0000000000000000 3
> > check xx_v 23 0.0000000000000000 0.0000000000000000 3
> > check xx_v 24 0.0000000000000000 0.0000000000000000 3
> >
> > ======The vector x is :
> > Process [0]
> > 4000
> > 4000
> > 4000
> > 4000
> > 4000
> > 3000
> > 3000
> > Process [1]
> > 3000
> > 3000
> > 3000
> > 2000
> > 2000
> > 2000
> > Process [2]
> > 2000
> > 2000
> > 1000
> > 1000
> > 1000
> > 1000
> > Process [3]
> > 1000
> > 0
> > 0
> > 0
> > 0
> > 0
> >
> >
> >
> >
> > > Date: Tue, 4 Jan 2011 17:50:11 -0600
> > > From: balay at mcs.anl.gov
> > > To: petsc-users at mcs.anl.gov
> > > Subject: Re: [petsc-users] error in calling VecGetArrayf90()
> > >
> > > Did you included "finclude/petscvec.h90" in your code - as the example did?
> > >
> > > satish
> > >
> > > On Tue, 4 Jan 2011, Peter Wang wrote:
> > >
> > > >
> > > > I am trying to obtain the value of each element of a solution Vector by KSPsolve().
> > > >
> > > > The variables are defined according the example of ex4f90.F in \petsc-3.1-p5\src\snes\examples\tutorials\ as following,
> > > >
> > > > PetscScalar, pointer :: xx_v(:)
> > > >
> > > > ...
> > > > call KSPSolve(ksp,b,x,ierr)
> > > > call VecView(x,PETSC_VIEWER_STDOUT_WORLD,ierr)
> > > >
> > > > call VecGetArrayF90(x,xx_v,ierr)
> > > > call VecRestoreArrayF90(x,xx_v,ierr)
> > > >
> > > > ...
> > > >
> > > > But, the error keeps coming out when call VecGetArrayF90(x,xx_v,ierr) and call VecRestoreArrayF90(x,xx_v,ierr) are not commented off.
> > > >
> > > >
> > > > The error information shows:
> > > > Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range
> > > >
> > > > [0]PETSC ERROR: --------------------- Stack Frames ------------------------------------
> > > > [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,
> > > > [0]PETSC ERROR: INSTEAD the line number of the start of the function
> > > > [0]PETSC ERROR: is given.
> > > > [0]PETSC ERROR: [0] F90Array1dCreate line 52 src/sys/f90-src/f90_cwrap.c
> > > > [0]PETSC ERROR: --------------------- Error Message ------------------------------------
> > > >
> > > > I checked the code according the example, but cannot see any difference to that. Just don't know why the pointer array xx_v doesn't work here? Thanks.
> > > >
> > > >
> > >
> >
>
--
-------------------------------------
Ethan Coon
Post-Doctoral Researcher
Mathematical Modeling and Analysis
Los Alamos National Laboratory
505-665-8289
http://www.ldeo.columbia.edu/~ecoon/
-------------------------------------
More information about the petsc-users
mailing list