VecView behaviour

[Barry Smith]

    Hmm, it sounds like the difference between local "ghosted" vectors  
and the global parallel vectors. But I do not understand why any of  
the local vector entries would be zero.
Doesn't the vector X that is passed into KSP (or SNES) have the global  
entries and uniquely define the solution? Why is viewing that not right?

    Barry

On Jun 2, 2009, at 3:23 PM, Andreas Grassl wrote:

> Barry Smith schrieb:
>>
>> On May 29, 2009, at 4:34 AM, Andreas Grassl wrote:
>>
>>> Hello,
>>>
>>> I'm working with the PCNN preconditioner and hence with
>>> ISLocalToGlobalMapping.
>>> After solving I want to write the solution to an ASCII-file where  
>>> only
>>> the
>>> values belonging to the "external" global numbering are given and  
>>> not
>>> followed
>>                                      ^^^^^^^^^^^^^^^^^^^^^^^
>>>
>>> by the zeros.
>>
>> What do you mean? What parts of the vector do you want?
>
> I want the first actdof entries
>
> actdof is the number of DOF the system has.
> the values of indices is in the range of 0 to actdof-1.
> I create the mapping by
> ISLocalToGlobalMappingCreate(commw,ind_length,indices,&gridmapping);
>
> Due to the "existence" of interface DOF's the sum over all  
> ind_length is
> greather than actdof, namely the size of the Vectors, but only  
> actdof entries of
> this Vector are nonzero, if I view it.
>
>>>
>>> Currently I'm giving this commands:
>>>
>>> ierr =
>>> PetscViewerSetFormat 
>>> (viewer,PETSC_VIEWER_ASCII_SYMMODU);CHKERRQ(ierr);
>>> ierr = VecView(X,viewer);CHKERRQ(ierr);
>
> I hope you got an idea, what problem I have.
>
> Cheers,
>
> ando
>
> -- 
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