The global index starts at Istart - but the array index starts at 1 [for fortran array]
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. > > > > > > > > >
