Thanks, Matt. It seems DMPlexComputeCellGeometryFEM works well with the quadrature points to deliver Jacobian and inverse one. Will it be a good choice ?
Have a good night. Thanks, On Fri, Jun 23, 2023 at 10:33 AM Matthew Knepley <[email protected]> wrote: > On Fri, Jun 23, 2023 at 10:28 AM neil liu <[email protected]> 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/> >
