[petsc-users] PetscSplitOwnerShip()

[(Rebecca) Xuefei YUAN]

Dear Matt,

Thanks for your reply. I did not partition by my own, and even if I  
use VecLoadIntoVector(), the same error shows up.

Anything wrong with it?

Cheers,

Rebecca



Quoting Matthew Knepley <knepley at gmail.com>:

> If you do your own partitioning, you need to use VecLoadIntoVector() with a
> Vec you get from the DA.
>
>    Matt
>
> On Tue, Mar 9, 2010 at 5:16 PM, (Rebecca) Xuefei YUAN
> <xy2102 at columbia.edu>wrote:
>
>> Hi,
>>
>> I ran np=4 for a small (-da_grid_x 6, -da_grid_y 5) problem, with
>> PETSC_STENCIL_BOX and width=2, dof = 4.
>>
>> When I use vecLoad() to load the binary file with the following set:
>>
>>    PetscViewerBinaryOpen(PETSC_COMM_WORLD,fileName,FILE_MODE_READ,&viewer);
>>    VecLoad(viewer,PETSC_NULL,&FIELD);
>>    ierr = DAVecGetArray(da2_4,FIELD,&field);CHKERRQ(ierr);
>>
>>    ierr = DAVecRestoreArray(da2_4,FIELD,&field);CHKERRQ(ierr);
>>    ierr = VecDestroy(FIELD);CHKERRQ(ierr);
>>    ierr = DADestroy(da2_4);CHKERRQ(ierr);
>>    ierr = PetscViewerDestroy(viewer);CHKERRQ(ierr);
>>
>> However, I got the error messages as below:
>>
>> [0]PETSC ERROR: DAVecGetArray() line 53 in src/dm/da/src/dagetarray.c
>> Vector local size 32 is not compatible with DA local sizes 36 100
>>
>> [1]PETSC ERROR: DAVecGetArray() line 53 in src/dm/da/src/dagetarray.c
>> Vector local size 32 is not compatible with DA local sizes 36 100
>>
>> [2]PETSC ERROR: DAVecGetArray() line 53 in src/dm/da/src/dagetarray.c
>> Vector local size 28 is not compatible with DA local sizes 24 80
>>
>> [3]PETSC ERROR: DAVecGetArray() line 53 in src/dm/da/src/dagetarray.c
>> Vector local size 28 is not compatible with DA local sizes 24 80
>>
>> Then I tracked down and tried to find how this 32,32,28,28 coming from.
>>
>> It turns out that my da2_4 has the parameters at each processor:
>>
>>
>>      xs xe ys ye x y Xs Xe Ys Ye Nl base nlocal Nlocal
>> p0:   0  12 0  3 12 3 0  20 0  5  100 0   100    36
>> p1:   12 24 0  3 12 3 4  24 0  5  100 36  100    36
>> p2:   0  12 3  5 12 2 0  20 1  5  80  72   80    24
>> p3:   12 24 3  5 12 2 4  24 1  5  80  96   80    24
>>
>> and deep in
>>
>> #0  PetscSplitOwnership (comm=-2080374782, n=0x8a061b4, N=0x8a061b8)
>>    at psplit.c:81
>> #1  0x08628384 in PetscLayoutSetUp (map=0x8a061b0) at pmap.c:140
>> #2  0x08618320 in VecCreate_MPI_Private (v=0x8a05c50, alloc=PETSC_TRUE,
>>    nghost=0, array=0x0) at pbvec.c:182
>> #3  0x08618ba7 in VecCreate_MPI (vv=0x8a05c50) at pbvec.c:232
>> #4  0x085f1554 in VecSetType (vec=0x8a05c50, method=0x885dd0b "mpi")
>>    at vecreg.c:54
>> #5  0x085ec4f0 in VecSetTypeFromOptions_Private (vec=0x8a05c50)
>>    at vector.c:1335
>> #6  0x085ec909 in VecSetFromOptions (vec=0x8a05c50) at vector.c:1370
>> #7  0x085d7a7e in VecLoad_Binary (viewer=0x89f70b0, itype=0x885ce3d "mpi",
>>    newvec=0xbfe148e4) at vecio.c:228
>> #8  0x085d70e4 in VecLoad (viewer=0x89f70b0, outtype=0x885ce3d "mpi",
>>    newvec=0xbfe148e4) at vecio.c:134
>> #9  0x0804f140 in FormInitialGuess_physical (dmmg=0x89a2880, X=0x89b34f0)
>>    at vecviewload_out.c:390
>> #10 0x08052ced in DMMGSolve (dmmg=0x89a2720) at damg.c:307
>> #11 0x0804d479 in main (argc=-1, argv=0xbfe14cd4) at vecviewload_out.c:186
>>
>> it says that
>>
>>      *n = *N/size + ((*N % size) > rank);
>>
>> where *N = 30; size = 4; rank = 0,1,2,3, in such a case, this gives me
>>
>> *n = 32,32,28,28 for pro0,1,2,3, separately.
>>
>> Where could be wrong with this mismatch of the local vector size and da
>> local size(excluding ghost pts or including ghost pts)?
>>
>> Thanks so much!
>>
>> Rebecca
>>
>>
>
>
> --
> 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
>



-- 
(Rebecca) Xuefei YUAN
Department of Applied Physics and Applied Mathematics
Columbia University
Tel:917-399-8032
www.columbia.edu/~xy2102