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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.<BR>
<BR>
The protion of the code to display them on the monitor is like as following: <BR>
call MatGetOwnershipRange(A,Istart,Iend,ierr)<BR> call VecGetArrayF90(x,xx_v,ierr) ! Vector x is matched with Matrix A in the same communicator<BR>
<BR>
write(*,*)xx_v,myid ! write the poiner array together<BR>
<BR> do i=Istart,Iend-1<BR> 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)<BR> enddo <BR>
<BR>
<BR>
=========The result is as following: ( the values of the elements from 7 to 20 are not correct !!)<BR><BR>
3999.9999999999982 3999.9999999999982 3999.9999999999982 3999.9999999999982 3999.9999999999982 3000.0000000000005 3000.0000000000005 0<BR> <BR>
3000.0000000000009 3000.0000000000009 3000.0000000000009 2000.0000000000011 2000.0000000000011 2000.0000000000000 1<BR><BR>
2000.0000000000009 2000.0000000000009 1000.0000000000003 1000.0000000000003 1000.0000000000003 999.99999999999989 2<BR><BR>
1000.0000000000000 0.0000000000000000 0.0000000000000000 0.0000000000000000 0.0000000000000000 0.0000000000000000 3<BR><BR>
<BR>
check xx_v 0 0.0000000000000000 0.0000000000000000 0<BR> check xx_v 1 3999.9999999999982 3999.9999999999982 0<BR> check xx_v 2 3999.9999999999982 3999.9999999999982 0<BR> check xx_v 3 3999.9999999999982 3999.9999999999982 0<BR> check xx_v 4 3999.9999999999982 3999.9999999999982 0<BR> check xx_v 5 3999.9999999999982 3999.9999999999982 0<BR> check xx_v 6 3000.0000000000005 3000.0000000000005 0<BR> check xx_v 7 1.99665037664579820E-314 1.99665037664579820E-314 1<BR> check xx_v 8 2.61360726650019422E-321 2.61360726650019422E-321 1<BR> check xx_v 9 7.90505033345994471E-323 7.90505033345994471E-323 1<BR> check xx_v 10 1.69759663277221785E-312 1.69759663277221785E-312 1<BR> check xx_v 11 6.16846344148335980E-317 6.16846344148335980E-317 1<BR> check xx_v 12 6.16846640587723485E-317 6.16846640587723485E-317 1<BR> check xx_v 13 6.16838982570212945E-317 6.16838982570212945E-317 2<BR> check xx_v 14 1.99665037664579820E-314 1.99665037664579820E-314 2<BR> check xx_v 15 6.19790333112210216E-317 6.19790333112210216E-317 2<BR> check xx_v 16 6.20255545324334334E-317 6.20255545324334334E-317 2<BR> check xx_v 17 6.20225061473985929E-317 6.20225061473985929E-317 2<BR> check xx_v 18 6.18242376037225006E-317 6.18242376037225006E-317 2<BR> check xx_v 19 6.16846640587723485E-317 6.16846640587723485E-317 3<BR> check xx_v 20 6.18113523716789609E-317 6.18113523716789609E-317 3<BR> check xx_v 21 0.0000000000000000 0.0000000000000000 3<BR> check xx_v 22 0.0000000000000000 0.0000000000000000 3<BR> check xx_v 23 0.0000000000000000 0.0000000000000000 3<BR> check xx_v 24 0.0000000000000000 0.0000000000000000 3<BR>
<BR>
======The vector x is :<BR>
Process [0]<BR>4000<BR>4000<BR>4000<BR>4000<BR>4000<BR>3000<BR>3000<BR>Process [1]<BR>3000<BR>3000<BR>3000<BR>2000<BR>2000<BR>2000<BR>Process [2]<BR>2000<BR>2000<BR>1000<BR>1000<BR>1000<BR>1000<BR>Process [3]<BR>1000<BR>0<BR>0<BR>0<BR>0<BR>0<BR><BR><BR>
<BR> <BR>
> Date: Tue, 4 Jan 2011 17:50:11 -0600<BR>> From: balay@mcs.anl.gov<BR>> To: petsc-users@mcs.anl.gov<BR>> Subject: Re: [petsc-users] error in calling VecGetArrayf90()<BR>> <BR>> Did you included "finclude/petscvec.h90" in your code - as the example did?<BR>> <BR>> satish<BR>> <BR>> On Tue, 4 Jan 2011, Peter Wang wrote:<BR>> <BR>> > <BR>> > I am trying to obtain the value of each element of a solution Vector by KSPsolve(). <BR>> > <BR>> > The variables are defined according the example of ex4f90.F in \petsc-3.1-p5\src\snes\examples\tutorials\ as following,<BR>> > <BR>> > PetscScalar, pointer :: xx_v(:)<BR>> > <BR>> > ...<BR>> > call KSPSolve(ksp,b,x,ierr)<BR>> > call VecView(x,PETSC_VIEWER_STDOUT_WORLD,ierr)<BR>> > <BR>> > call VecGetArrayF90(x,xx_v,ierr)<BR>> > call VecRestoreArrayF90(x,xx_v,ierr)<BR>> > <BR>> > ...<BR>> > <BR>> > But, the error keeps coming out when call VecGetArrayF90(x,xx_v,ierr) and call VecRestoreArrayF90(x,xx_v,ierr) are not commented off.<BR>> > <BR>> > <BR>> > The error information shows:<BR>> > Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range<BR>> > <BR>> > [0]PETSC ERROR: --------------------- Stack Frames ------------------------------------<BR>> > [0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,<BR>> > [0]PETSC ERROR: INSTEAD the line number of the start of the function<BR>> > [0]PETSC ERROR: is given.<BR>> > [0]PETSC ERROR: [0] F90Array1dCreate line 52 src/sys/f90-src/f90_cwrap.c<BR>> > [0]PETSC ERROR: --------------------- Error Message ------------------------------------<BR>> > <BR>> > 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.<BR>> > <BR>> > <BR>> <BR>                                            </body>
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