On Fri, Jun 23, 2023 at 10:12 PM neil liu <liufi...@gmail.com> wrote:
> Thanks, Matt. > It seems DMPlexComputeCellGeometryFEM works well with the quadrature > points to deliver Jacobian and inverse one. > Will it be a good choice ? > Yes, it is intended to compute these quantities for you. Let me know if it does not do what you want. Thanks, Matt > Have a good night. > > Thanks, > > On Fri, Jun 23, 2023 at 10:33 AM Matthew Knepley <knep...@gmail.com> > wrote: > >> On Fri, Jun 23, 2023 at 10:28 AM neil liu <liufi...@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/> >> > -- 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/>