Hi Jed, On Wed, Jun 1, 2011 at 4:11 PM, Jed Brown <jed at 59a2.org> wrote: > 2D or 3D? What kind of elements?
This is 3D with linear tets. > The overhead of the profiling can be nontrivial for small elements. How does > the run-time change if you deactivate that event? > How much of the overall time is spent in matrix assembly (your code plus > MatSetValues)? I actually started off by profiling the application with HPCToolkit, and only turned on the PETSc profiling as a sanity check and to send to this list. The results are pretty consistent with the profiling from HPCToolkit. I ran without -log_summary and it was about 8% faster. > It looks like the linear solve is around 18 iterations. For first order > elements, that is probably too many for matrix-free with a lagged Jacobian > to pay off. The trade-off is much more favorable for higher order elements, > or if the preconditioner is better. There are several linear solves, and some of them do pretty well with just cg/jacobi. Perhaps we could move a few of the solves to matrix-free. Thanks, John
