dolfin team mailing list archive

[Anders Logg <logg@xxxxxxxxx>]

Fantastic!

We could probably speed it up another factor 2 with some work, but
these numbers are already great.

Is it necessary to have an if-else for the plasticity, or could you
introduce a parameter (Function) and put the if-else in the evaluation
operator of that parameter?

Did you make any nice movies? If you have time, put some movies on
http://www.fenics.org/gallery/ and some images (300x300) with some
text.

/Anders

On Wed, Jun 01, 2005 at 11:26:42PM +0200, Johan Jansson wrote:
> Hi!
> 
> The updated Lagrangian elasticity module now works with FFC. The only
> important missing parts are viscosity (trivial) and plasticity (might
> need some work in FFC to support if-else type operations in forms).
> 
> I've done some benchmarks comparing the old assembly with the FFC
> assembly, and the results are very promising.
> 
> I've tested with a mesh consisting of 33k cells (large enough so that
> the assembly dominates). The total running time for the test with the
> old module is 1100s, the total running time for the test with the FFC
> module is 43s. This is a speedup of a factor 26. If we look at only
> the time spent assembling, then the time for one assembly (there's one
> assembly per time step, 100 time steps in total) is 11s for the old
> module and 0.27s for the FFC module. This is a speedup of a factor 41.
> 
> Perhaps more optimizations could/can be done both for the old module
> and the FFC module, and times will vary when terms are added, but it's
> reasonable to expect the speedup to be a factor 10-100 for this form.
> 
> One good sign that the assembly is now efficient is that at one point
> the bottleneck turned out to be a naive elementwise division of two
> vectors that is done in the solver. Implementing it with a PetSc
> operation made the assembly come out on top again. I haven't tested
> with a real profiler yet, that would give an even better picture of
> where the time is spent.
> 
> Here's the data in a table:
> 
> Mesh01:
> 
> Reading mesh from file "mymesh01.xml.gz".
> Computing mesh connectivity:
>   Found 6545 nodes
>   Found 32768 cells
>   Created 41360 edges
>   Created 67584 faces
> 
> old:
> total - 1100s
> assembling - 11s
> 
> ffc:
> total - 43s
> assembling - 0.27s
> 
> 
> A comment on the last two numbers: assembling a mass matrix (done only
> once) takes 7s, and probably as much time is spent reading the mesh.
> 
>   Johan
> 
> 
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-- 
Anders Logg
Research Assistant Professor
Toyota Technological Institute at Chicago
http://www.tti-c.org/logg/