Re: [petsc-dev] BlockGetIndices and GetBlockIndices

[Smith, Barry F. via petsc-dev]

> On Oct 16, 2019, at 9:41 AM, Stefano Zampini via petsc-dev 
> <petsc-dev@mcs.anl.gov> wrote:
> 
> I just took a look at the ISGENERAL code. ISSetBlockSize_General just sets 
> the block size of the layout (??)
> ISGetIndices always return the data->idx memory.
> So, a more profound question is: what is the model behind setting the block 
> size on a ISGENERAL? And on a IS in general?

   I still don't understand why IS even has a layout so I was lost long ago.

   ISSetBlockSize_*() appear to be complete gibberish for ISGeneral, ISBlock, 
and ISStride! 

> 
>> On Oct 16, 2019, at 4:37 PM, Jed Brown <j...@jedbrown.org> wrote:
>> 
>> Stefano Zampini via petsc-dev <petsc-dev@mcs.anl.gov> writes:
>> 
>>>> Thoughts and/or comments? Would it make sense to add an 
>>>> ISGetBlockIndices/ISRestoreBlockIndices or would that be too confusing for 
>>>> the user?

   Seems insane, ISGetBlockIndices/ISRestoreBlockIndices() should not only not 
exist the entire absurd SSetBlockSize() concept should be removed. 

   Barry


>>> 
>>> That would be more general and I think it makes sense, and should pair with 
>>>  ISGetBlockSize
>> 
>> What happens if you call ISGetBlockIndices on an ISGeneral for which
>> blocks are not contiguous?
>