Subject: [Syfi-dev] [HG syfi] Updated tables after new benchmarks for quadrature code, and inserted scaled Deal.II results in tables.

From: [email-masked] (SyFi)
Date: Thu, 8 Nov 2007 13:37:16 +0100 (CET)

One or more new changesets pushed to the primary SyFi repository.
A short summary of the last three changesets is included below.

changeset:   954:bfbededacaa98d463417c39774da817795ef88de
tag:         tip
user:        "Martin Sandve Alnæs <[email-masked]>"
date:        Thu Nov 08 13:37:04 2007 +0100
files:       benchmarks_v2/results/dealresults.py benchmarks_v2/results/reports/martinal_results.py benchmarks_v2/results/reports/report_convection_jacobi.py benchmarks_v2/results/reports/report_convection_matrix.py benchmarks_v2/results/reports/report_convection_vector.py benchmarks_v2/results/reports/report_mass.py benchmarks_v2/results/reports/report_stiffness.py benchmarks_v2/results/reports/tabletools.py doc/efficiency/efficiency.tex doc/efficiency/tables.tex python/sfc/Form.py python/sfc/Integral.py
description:
Updated tables after new benchmarks for quadrature code, and inserted scaled Deal.II results in tables.

changeset:   953:3edea30db9e1dd1217f8ad6ee130b8d06aae4115
user:        "Martin Sandve Alnæs <[email-masked]>"
date:        Wed Nov 07 14:17:54 2007 +0100
files:       benchmarks_v2/sfc_quad_rhs_vector.py python/sfc/Form.py python/sfc/Integral.py
description:
Rewritten Jacobi algorithm.

changeset:   952:7da1dc52fd076268fbb4f54538c0bee94749c7d9
user:        "Kent-Andre Mardal <[email-masked]>"
date:        Mon Nov 05 12:21:31 2007 +0100
files:       doc/efficiency/efficiency.tex
description:
updated prelim

----------------------------------------------------------------------
For more details, visit http://www.fenics.org/hg/syfi

---

From: Anders Logg <[email-masked]>
Date: Thu, 8 Nov 2007 23:47:06 +0100

Which form is "source element vector"? Is it the linear form

  L = v*f*dx?

How is this computed by SyFi (tabulate_tensor)? It would be
interesting to compare with the FFC code.

I'm not sure what your timeframe is but maybe you should also include
timings for FErari-optimized FFC code (in which case you need to bug
me about activating the optimization again in FFC). We did a series of
benchmarks for comparing plain FFC code with FErari code a while back
and the local speedups were typically between a factor 1-4:

    http://www.femcenter.org/pub/preprints/phiprint-2007-04.pdf

/Anders

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> SyFi-dev mailing list
> [email-masked]
> http://fenics.org/mailman/listinfo/syfi-dev

---

From: "Martin Sandve Alnæs" <[email-masked]>
Date: Fri, 9 Nov 2007 00:24:01 +0100

> Which form is "source element vector"? Is it the linear form

Yes.

> interesting to compare with the FFC code.

I can post the code tomorrow. SyFi is faster than FFC in this case,
while FFC is faster than SyFi for the Laplace matrix. Mass matrices
don't differ. Also, the SyFi-generated quadrature can be faster than
both FFC and "regular" SyFi code in some cases, in particular for the
convection vector L = dot(dot(u,grad(u)),v)*dx.

> me about activating the optimization again in FFC).

Bug bug :)

> We did a series of

I'll read this tomorrow. Also, Ola is working on implementing a
factorization algorithm I found in an article earlier, and if he
manages to get it working we could test that as well or use it to
replace the current optimization (a naive implementation of "common
subexpression elimination"). The current naive algorithm gives speedup
factors of around 0.9 to 3.5, not easily predictable.

Most of the article will be unchanged by these additional results, so
if we can get them in time (don't know when "in time" is), we can
include them.

--
Martin

---

From: Kent-Andre Mardal <[email-masked]>
Date: Fri, 09 Nov 2007 10:45:37 +0100

>     http://www.femcenter.org/pub/preprints/phiprint-2007-04.pdf

Ok, I thought the speed-up was < 50%, I don't know where I got that
from. I think you said something like that but it was probably some time
ago. 

Anyway, the element matrix calculations only take a few prosent of the
total time (grid + element calc. + matrix assembly). Is this consistent 
with your timings. 

We will have a look at your preprint. 

Kent

---

From: Anders Logg <[email-masked]>
Date: Sat, 10 Nov 2007 11:09:43 +0100

> convection vector L = dot(dot(u,grad(u)),v)*dx.

ok, interesting. Look forward to seeing what the differences are.

> if we can get them in time (don't know when "in time" is), we can

ok.

/Anders

---

From: Anders Logg <[email-masked]>
Date: Sat, 10 Nov 2007 11:13:44 +0100

> from. I think you said something like that but it was probably some time

Yes, typically < 50% (but sometimes more) for the global assembly.
For the local computation of the element tensor, the speedups are
better.

> total time (grid + element calc. + matrix assembly). Is this consistent 

It varies. The best global speedup we got was a factor 2.8 so in that
case the local computation must have been a significant portion of the
overall time.

/Anders