I suspect the problem is I don't have MTL4 installed on my desktop so it defaults to uBlas for me. I don't have time to check now but will check later. So, don't trust my results for MTL4 just yet.
We should probably issue an error when the backend is not available. -- Anders On Fri, Aug 08, 2008 at 10:14:33AM +0100, Garth N. Wells wrote: > > > Anders Logg wrote: > > On Thu, Aug 07, 2008 at 10:32:56PM +0100, Garth N. Wells wrote: > >> Something I don't understand is the time for creating the sparsity > >> pattern for MTL4 when it involves no operations? > > > > MTL4Factory still returns a sparsity pattern. I wasn't aware that MTL4 > > didn't need one. MT4Factory should return 0 in createPattern() and > > MTL4SparsityPattern can then be removed. > > > > We're cheating a bit at the moment. MLT4 needs to know the maximum > number on non-zeroes on any row. We're just guessing this for now. > > Currently, MTLSparsityPattern::insert(..) is empty. If you look at my > benchmark results, the cost of building the MTLSparsityPattern is > negligible, but in yours and Ilmar's it's comparable to the cost of > building the sparsity pattern for uBLAS and PETSc. I have no idea what's > going on. I thought that the overhead was in SparsityPattern::insert(), > which is what my results indicate, whereas yours indicate that the > overhead is considerable in SparsityPatternBuilder. > > > I can fix this later today if you don't fix it before. > > > > Let's leave it as id for now. > > >> Why is uBLAS now faster than before (relative)? > > > > I didn't notice. I might have made an apt-get upgrade in between. > > I don't think anything has changed for uBlas in the code. > > > > The only change I made was to SparsityPattern, which seems to have given > you a bigger speed-up than it did me. > > Garth > > > > > > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > DOLFIN-dev mailing list > > [email protected] > > http://www.fenics.org/mailman/listinfo/dolfin-dev > > _______________________________________________ > DOLFIN-dev mailing list > [email protected] > http://www.fenics.org/mailman/listinfo/dolfin-dev
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