dolfin team mailing list archive

["Garth N. Wells" <gnw20@xxxxxxxxx>]

Something I don't understand is the time for creating the sparsity 
pattern for MTL4 when it involves no operations?

Why is uBLAS now faster than before (relative)?

Garth

Anders Logg wrote:
> I have made some changes to allow a backend to notify that it does not
> need to be initialized by a sparsity pattern. If the factory function
> createSparsityPattern() returns 0, then the assembler will not build
> the sparsity pattern.
>
> I have tried this for the STL backend (earlier called AssemblyMatrix).
> No sparsity pattern is computed and no preallocation is made, just
> inserting directly into the vector of vectors using a linear search
> and this gives very good speedups, see here:
>
>   http://www.fenics.org/wiki/Benchmark
>
> STL is 36% faster than all other backends for the NS testcase.
>
> It is also about just as fast as the other backends for the assembly
> step ("Assemble cells") even if no preallocation is made.
>
>
>
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