On Thu, Jun 02, 2011 at 10:46:29AM +0100, Garth N. Wells wrote: > > > On 02/06/11 10:26, Anders Logg wrote: > > On Thu, Jun 02, 2011 at 10:07:59AM +0100, Garth N. Wells wrote: > >> > >> > >> On 01/06/11 23:46, Anders Logg wrote: > >>> Have you checked that there is no performance penalty? > >> > >> I just have - evaluating a Legendgre polynomial 10k times at the same > >> point is just noise with both methods (of the order 10^-5 - 10^-4 s). > > > > It may be noise for some applications, but not for others. I'm not > > sure this is a bottle-neck for the ODE code (Benjamin will know) but > > we need to evaluate Legendre polynomials of degree > 100 many times > > and then it may not be noise. > > > > For very high degree (e.g. 200) Boost is marginally faster.
Sounds promising then. > >> The Boost code is slightly slower because it doesn't cache the values > >> (which is nice not to do), but may be faster if the call is inlined. > >> It's not possible to inline it at the moment because of clashes between > >> tr1:tuple and boost::tuple (Boost bug, I suspect). Old and new are the > >> same when evaluating at different points. > > > > Let's wait for Benjamin to comment. > > > > The speed is about the same (with scope to improve the speed for Boost) > for unique values. The caller should be responsible for caching, if > desired, since it can lead to memory blow out. > > Legendre does not appear in the ode code. It only appears in the > computation of quadrature schemes. True, but the quadrature schemes are used in the ode code. -- Anders > Garth > > > > >> Garth > >> > >> > >>> Benjamin has > >>> worked quite hard on optimizing some of the basic math routines (in > >>> some cases by many many orders of magnitude). > >>> > >>> Benjamin, can you take a look that it still works? > >>> > >> > >> _______________________________________________ > >> Mailing list: https://launchpad.net/~dolfin > >> Post to : dolfin@lists.launchpad.net > >> Unsubscribe : https://launchpad.net/~dolfin > >> More help : https://help.launchpad.net/ListHelp _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
