Pierre Jolivet via petsc-dev <petsc-dev@mcs.anl.gov> writes:
>> On 21 Oct 2019, at 7:52 AM, Smith, Barry F. <bsm...@mcs.anl.gov> wrote:
>>
>>
>>
>>> On Oct 21, 2019, at 12:23 AM, Pierre Jolivet <pierre.joli...@enseeiht.fr>
>>> wrote:
>>>
>>>
>>>
>>>> On 21 Oct 2019, at 7:11 AM, Smith, Barry F. <bsm...@mcs.anl.gov> wrote:
>>>>
>>>>
>>>>
>>>>> On Oct 20, 2019, at 11:52 PM, Pierre Jolivet <pierre.joli...@enseeiht.fr>
>>>>> wrote:
>>>>>
>>>>>
>>>>>
>>>>>> On 21 Oct 2019, at 6:42 AM, Smith, Barry F. <bsm...@mcs.anl.gov> wrote:
>>>>>>
>>>>>> Could you provide a use case where you want to access/have a block size
>>>>>> of a IS that is not an ISBlock?
>>>>>
>>>>> In the end, all I really want is get access to the underlying
>>>>> is->data->idx without having to worry about the subclass of is.
>>>>> I don’t have such a use case, but I don’t think this is really related to
>>>>> what I want to achieve (or maybe it is…).
>>>>
>>>> ISGetIndices()
>>>
>>> Not true for ISBlock with bs > 1.
>>
>> Certainly suppose to be, is there a bug?
>>
>> static PetscErrorCode ISGetIndices_Block(IS in,const PetscInt *idx[])
>> {
>> IS_Block *sub = (IS_Block*)in->data;
>> PetscErrorCode ierr;
>> PetscInt i,j,k,bs,n,*ii,*jj;
>>
>> PetscFunctionBegin;
>> ierr = PetscLayoutGetBlockSize(in->map, &bs);CHKERRQ(ierr);
>>
>> Dang, there is that stupid layout stuff again. Who put this crap in.
>>
>> ierr = PetscLayoutGetLocalSize(in->map, &n);CHKERRQ(ierr);
>> n /= bs;
>> if (bs == 1) *idx = sub->idx;
>> else {
>
> There it is, I don’t want this if/else. ISGetBlockIndices would have been a
> function always returning sub->idx.
Your code still can't skip the branch because ISGeneral can have bs>1.
Block size in IS means "these indices go together" while ISBlock imposes
the further constraint: "indices in each block are contiguous". So you
can't just take the code you quoted where it returns the raw idx:
if (!isblock) {
ISGetIndices(is,&indices);
ISLocalToGlobalMappingCreate(comm,1,n,indices,PETSC_COPY_VALUES,mapping);
ISRestoreIndices(is,&indices);
} else {
ISGetBlockSize(is,&bs);
ISBlockGetIndices(is,&indices);
ISLocalToGlobalMappingCreate(comm,bs,n/bs,indices,PETSC_COPY_VALUES,mapping);
ISBlockRestoreIndices(is,&indices);
}
PetscErrorCode ISGetBlockSize(IS is,PetscInt *size)
{
PetscErrorCode ierr;
PetscFunctionBegin;
ierr = PetscLayoutGetBlockSize(is->map, size);CHKERRQ(ierr);
PetscFunctionReturn(0);
}
