[petsc-users] How to view petsc array?

[Dave May]

On 19 August 2015 at 10:54, TAY wee-beng <zonexo at gmail.com> wrote:

>
> On 21/7/2015 7:28 PM, Matthew Knepley wrote:
>
> On Tue, Jul 21, 2015 at 1:35 AM, TAY wee-beng <zonexo at gmail.com> wrote:
>
>> Hi,
>>
>> I need to check the contents of the array which was declared using:
>>
>> PetscScalar,pointer ::
>> u_array(:,:,:),v_array(:,:,:),w_array(:,:,:),p_array(:,:,:)
>>
>> I tried to use :
>>
>> call PetscViewerASCIIOpen(MPI_COMM_WORLD,"pres.txt",viewer,ierr)
>>
>> call VecView(p_array,viewer,ierr)
>>
>> or
>>
>> call MatView(p_array,viewer,ierr)
>>
>> call PetscViewerDestroy(viewer,ierr)
>>
>> but I got segmentation error. So is there a PETSc routine I can use?
>
>
> No. Those routines work only for Vec objects. You could
>
>  a) Declare a DMDA of the same size
>
>  b) Use DMDAVecGetArrayF90() to get out the multidimensional array
>
>  c) Use that in your code
>
>  d) Use VecView() on the original vector
>
>
> Hi,
>
> Supposed I need to check the contents of the u_array which was declared
> using:
>
> PetscScalar,pointer :: u_array(:,:,:)
>
> call
> DMDACreate3d(MPI_COMM_WORLD,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DM_BOUNDARY_NONE,DMDA_STENCIL_STAR,size_x,size_y,&
>
>
> size_z,1,PETSC_DECIDE,PETSC_DECIDE,1,stencil_width,lx,PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,da_u,ierr)
>
> call DMDAVecGetArrayF90(da_u,u_local,u_array,ierr)
>
> call PetscViewerASCIIOpen(MPI_COMM_WORLD,"u.txt",viewer,ierr)
>
> call VecView(array,viewer,ierr)
>


The first argument of VecView must be of type Vec (as Matt noted).
It looks you are passing in an array of PetscScalar's.



>
> call PetscViewerDestroy(viewer,ierr)
>
> Is this the correct way?
>
>
>    Matt
>
>
>>
>> --
>> Thank you
>>
>> Yours sincerely,
>>
>> TAY wee-beng
>>
>>
>
>
> --
> 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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