On Thu, Jul 17, 2008 at 11:19:09PM +0100, Garth N. Wells wrote: > It's now easy to play with the sandbox programs in > > sandbox/mtl4/poisson_bench > sandbox/mtl4/nse_bench > > All you need to do is set the environment variable MTL4_DIR to point to > the MTL4 source, and then run scons in the relevant directory.
Works fine here.
> What's clear is that we should take a look at the efficiency of the
> sparsity computation. In particular, there are some virtual functions
> calls which can possibly be avoided, or at least minimised. Even when
> using MTL4 for general problems it will be necessary to compute some
> form of a sparsity pattern to estimate the number of nonzeros per row.
>
> It would be useful to use the same assembler for MTL4 as is used for
> other linear algebra backends to see what influence that has.
I think it would be good to move the MTL4 interface into dolfin/la as
soon as possible. The missing functions can return an error until they
have been fixed.
Then we should include MTL4 in the main assembly benchmark which is
bench/fem/assembly/
If possible, we should figure out a way to run this benchmark
regularly (like we do with the buildbot) so we can check for
regressions.
> The results for uninitialised MTL4 matrices are indeed impressive, as is
> the re-assembly time for Navier-Stokes.
>
> uBLAS and PETSc deliver almost identical performance for all tests.
Here's what I get on my laptop (for n = 32). Do you get similar
results?
Summary: MTL4 uBLAS
First matrix assembly 2.95 7.99
Matrix re-assembly 2.51 3.58
Vector assembly 2.38 2.49
--
Anders
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