OK. Thanks a lot this really makes things clearer. Best regars, B. M. R.
2010/6/7 Wolfgang Bangerth <[email protected]> > > > Triangles/tetrahedra are not supported in deal.II. As the answer in the > FAQ > > says this is a decision related to performance of the underlying data > > structures. I would like to know if the only reason is the compiler > > optimization of loops or if there are more reasons > > related to refinement/adaptative strategies, multigrid methods or > something > > else. > > > > It is also unclear to me why with triangles/tetrahedra this is not > possible > > (compiler optimizations). > > Many of the same things would be possible if you had *only* triangles and > tets. For example you could still determine the number of vertices of a > cell > at compile time. These optimizations just wouldn't work any more if you > *mixed* tets and hexes, for example. > > But there's another class of optimizations that are possible on quads and > hexes because everything is a tensor product (refinement rules, quadrature > formulas, shape functions, etc). Some of this may lead to faster code if > you > can optimize based on it, but a lot of it simply leads to much smaller (and > consequently likely more correct) code because you only have to implement > the > 1d case and get the rest by tensor products. This typically isn't the case > for triangles or tets where quadrature formulas and shape functions can not > always be derived from 1d-representations. > > Best > W. > > ------------------------------------------------------------------------- > Wolfgang Bangerth email: [email protected] > www: > http://www.math.tamu.edu/~bangerth/<http://www.math.tamu.edu/%7Ebangerth/> > >
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