On Tue, Jun 22, 2010 at 10:31 AM, Garth N. Wells <gn...@cam.ac.uk> wrote: > > > On 22/06/10 07:05, Andy Ray Terrel wrote: >> >> On Tue, Jun 22, 2010 at 6:15 AM, Anders Logg<l...@simula.no> wrote: >>> >>> On Tue, Jun 22, 2010 at 01:04:27PM +0200, Kristian Oelgaard wrote: >>>> >>>> On 21 June 2010 23:16, Kent Andre<kent-...@simula.no> wrote: >>>>> >>>>> Strange. I used dorsal to compile the dev versions of the various >>>>> packages. Dolfin, ffc, and sfc are only a few days old. >>>>> >>>>> But do you have any suggestions for how to optimize the FFC generated >>>>> code ? I have used quadrature here, tensor representation is not good >>>>> in this application. >>>> >>>> I had a look at the generated code from FFC and SyFi >>>> (which by the way is a real pain when PyDOLFIN is involved) >>>> >>>> and realised that your comparison is not fair. >>>> FFC uses the UFL algorithm estimate_total_polynomial_degree() to >>>> compute the quadrature_degree. >>>> SFC uses (in this case) the UFL algorithm estimate_quadrature_degree() >>>> which is less conservative. >>>> >>>> This results in FFC using 25 integration points to compute the >>>> integral while SFC just uses 3. >>>> >>>> If you use the option: >>>> >>>> parameters ["form_compiler"]["quadrature_degree"] = "2" >>>> >>>> the comparison is _more_ fair and the numbers are almost the same. >>>> SFC still uses 3 points, while FFC now uses 4 points which leads to my >>>> answer to your first question: >>>> "How should I optimize FFC?" :) >>>> >>>> https://blueprints.launchpad.net/ffc/+spec/simplex-quadrature >>> >>> I think either Andy Terrel or Peter Brune mentioned having worked out >>> some code for computing more efficient quadrature on simplices. There >>> was some discussion on adding that either to FIAT or FFC. >>> >>> What ever happened to that? >> >> The only fast quadrature I was working on was for the BCR wavelet >> rules for Calderon Zygmund operators. Rob has some recent stuff on >> fast quadrature using Bernstein basis. I'm not sure what Peter might >> have been doing. >> >> The local expert on quadrature at TACC, tells me the fastest schemes >> for quadrature for simplices is Grundmann-Möller for lower orders (< >> 20 ish) and the standard conical product for higher orders. >> >> @article{grundmann:282, >> author = {Axel Grundmann and H. M. M\"{o}ller}, >> collaboration = {}, >> title = {Invariant Integration Formulas for the $n$-Simplex by >> Combinatorial Methods}, >> publisher = {SIAM}, >> year = {1978}, >> journal = {SIAM Journal on Numerical Analysis}, >> volume = {15}, >> number = {2}, >> pages = {282-290}, >> url = {http://link.aip.org/link/?SNA/15/282/1}, >> doi = {10.1137/0715019} >> } >> > > I've pasted the above into > > https://blueprints.launchpad.net/ffc/+spec/simplex-quad > > Garth >
I added a few more notes and links on the blueprint. -- Andy >>> >>> -- >>> Anders >>> >>> -----BEGIN PGP SIGNATURE----- >>> Version: GnuPG v1.4.10 (GNU/Linux) >>> >>> iEYEARECAAYFAkwgmzsACgkQTuwUCDsYZdGcqwCgh1QCnNr0Jr1a2mcxDqheCpZ0 >>> ItkAn36nLWyr2RDO6pqgF4PX753ItHaU >>> =HnEK >>> -----END PGP SIGNATURE----- >>> >>> _______________________________________________ >>> Mailing list: https://launchpad.net/~ffc >>> Post to : ffc@lists.launchpad.net >>> Unsubscribe : https://launchpad.net/~ffc >>> More help : https://help.launchpad.net/ListHelp >>> >>> >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~ffc >> Post to : ffc@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~ffc >> More help : https://help.launchpad.net/ListHelp > > _______________________________________________ > Mailing list: https://launchpad.net/~ffc > Post to : ffc@lists.launchpad.net > Unsubscribe : https://launchpad.net/~ffc > More help : https://help.launchpad.net/ListHelp > _______________________________________________ Mailing list: https://launchpad.net/~ffc Post to : ffc@lists.launchpad.net Unsubscribe : https://launchpad.net/~ffc More help : https://help.launchpad.net/ListHelp
