Le vendredi 17 août 2018 15:26:37 UTC+2, Erik Bray a écrit : > > On Fri, Aug 17, 2018 at 2:02 PM Eric Gourgoulhon <egourg...@gmail.com > <javascript:>> wrote: > > > > Btw, I would be curious to know whether the notebook > > > http://nbviewer.jupyter.org/github/sagemanifolds/SageManifolds/blob/master/Worksheets/v1.3/SM_Kerr.ipynb > > > runs successfully with nproc>1 on Cygwin (I don't have any Windows > computer at hand either...) > > It works fine for me with nproc=8.
Good to hear! Many thanks for having tried. > A few of the lines are > frustratingly slow though, such as calls like `nabla(g)` (I'm > surprised this isn't cached when called repeatedly, especially when > it's the connection on g itself). Also computing the Ricci tensor > felt very slow. Is that normal? > Yes that's normal: most of CPU time is actually spent, not in the computation itself, but in simplifications of symbolic expressions (via Maxima). On my Linux laptop (Intel Core i7-6700HQ), with nproc=8, nabla(g) takes 5 s and the computation of the Ricci tensor takes 27 s. Regarding caching, nabla(T), where T is any tensor field, is not cached, even if T=g. The cached operations are g.connection() g.ricci() g.riemann() Best regards, Eric. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
