[petsc-users] Inquiry about PetscDTSimplexQuadrature .

[Matthew Knepley]

On Fri, Jun 23, 2023 at 10:28 AM neil liu <liufield at gmail.com> wrote:

> Dear Petsc developers,
>
> I am learning  *PetscDTSimplexQuadrature *and plan to use it.
> I found that, in the biunit simplex (tetra),
> (-1,-1,-1),(1,-1,-1),(-1,1,-1),(-1,-1,1),
> degree 1: npoints 4, the sum of weights = 4/3(the volume of this simplex)
> degree 2 : npoints 8;
> For my previous experience, I used Gauss quadrature rules, (npoints =4 ,
> 5, 11, 15).
> Then  I am curious what rule is Petsc using ?
>

There are two supported types:

  - Stroud Conical Quadrature

  - Minimal Symmetric Quadrature

I think we prefer symmetric when it is available.


> And is *PetscDTSimplexQuadrature *used by PetscFE?
>

Yes.

  Thanks,

    Matt


>
> Thanks a lot,
>
> Xiaodong
>
>

-- 
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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