On Mon, Mar 30, 2009 at 9:54 AM, Kirk, Benjamin (JSC-EG311) <[email protected]> wrote: >>>> The has_affine_map seems like a big payoff to avoid repeating the >>>> flops to determine it... >> >> I'd say we might want to profile that before we make too big a deal >> out of calling it a lot. For Quad4's it's two point subtractions and >> one equality test, for Hex8's it's at most 6 point subtractions and 4 >> equality tests, some of which may short-circuit if the element is not >> affine. > > Well, take a look at the Hex27, which would be the element for the CH > application I believe...
Hmm... hard to say, on average, how soon the test would short-circuit for non-affine elements. By the way, for an expensive element like a Hex27, I wonder if it would be faster to choose two arbitrary points in the element interior (a random 2 point quadrature rule) and compare computed Jacobian values at those 2 points to see if they're equal (constant Jacobian). I doubt you'd get a false positive but maybe you would? I also doubt this could be made faster (given the current interface for building an FE, quadrature rule, etc.) than Roy's geometric tests but it would be easier to estimate the computational expense of it without profiling. -- John ------------------------------------------------------------------------------ _______________________________________________ Libmesh-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-devel
