[petsc-users] chowiluviennacl

[Matthew Knepley]

On Wed, Jan 15, 2020 at 9:36 AM Xiangdong <epscodes at gmail.com> wrote:

> Can chowiluviennacl do ilu0?
>
> I need to solve a tri-diagonal system directly. If I apply the PCILU, I
> will obtain the exact solution with preonly + pcilu. However, the preonly +
> chowiluviennacl will not provide the exact solution. Any option keys to set
> the CHOWILUVIENNACL filling level or dropping off tolerance like the
> standard ilu?
>

No. However, such a scheme makes less sense here. This algorithm spawns a
individual threads for individual elements. Drop tolerance
is not less work, it is sparser, but that should not matter for a
tridiagonal system. Levels also is not applicable since you have only 1
level.

  Thanks,

    Matt


> Thank you.
>
> Best,
> Xiangdong
>
>
>
> On Tue, Jan 14, 2020 at 10:05 PM Matthew Knepley <knepley at gmail.com>
> wrote:
>
>> On Tue, Jan 14, 2020 at 9:56 PM Xiangdong <epscodes at gmail.com> wrote:
>>
>>> Dear Developers,
>>>
>>> I have a quick question about the chowiluviennacl. When I tried to use
>>> it, I found that it only works for np=1, not np>1. However, in the
>>> description of chowiluviennacl.cxx, it says "the ViennaCL Chow-Patel
>>> parallel ILU preconditioner".
>>>
>>
>> By parallel, this means shared memory parallelism on the GPU.
>>
>>
>>> I am wondering whether I am using it correctly. Does chowiluviennacl
>>> work for np>1?
>>>
>>
>> I do not believe so. I do not see why it could not be extended, but that
>> would mean writing some more code.
>>
>>   Thanks,
>>
>>     Matt
>>
>>
>>> In addition, are there option keys for the chowiluviennacl one can try?
>>> Thank you.
>>>
>>> Best,
>>> Xiangdong
>>>
>>
>>
>> --
>> 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
>>
>> https://www.cse.buffalo.edu/~knepley/
>> <http://www.cse.buffalo.edu/~knepley/>
>>
>

-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.cse.buffalo.edu/~knepley/>
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