Paul, It is true that the cpu time does not include any of the child processes, and also that in many cases most of the computation is done by those.
In this case the cardinality is either computed via a call to the libpari function ellap, or by running gp and calling the sea implementation there. The crossover is at 10^18 (as you can see by typing E.cardinality??) so your example is using sea via gp. Many people agree with you that it would be more useful to have the aggregate time. There are some complicated issues though, which I cannot remember (despite searching sage-devel). I expect that this will come up at SD6! Someone more expert in Sage than me might give you a better answer. John On 07/11/2007, Paul Zimmermann <[EMAIL PROTECTED]> wrote: > > Hi, > > it seems the cpu time reported by SAGE does not include that of the spawned > processes (sorry for using an old release :-) > > mermoz% sage > ---------------------------------------------------------------------- > | SAGE Version 2.8.10, Release Date: 2007-10-28 | > | Type notebook() for the GUI, and license() for information. | > ---------------------------------------------------------------------- > > sage: p=65257526772644948764799212887702573391887715235981530343703506731 > sage: time FindGroupOrder(p,489731259) > CPU times: user 0.87 s, sys: 0.07 s, total: 0.94 s > Wall time: 70.30 > 2^2 * 3^2 * 7 * 13 * 5521 * 589213 * 1103171 * 1149307 * 1310261 * 10091759 * > 63065897 * 120597437 * 48024231181 > > I doubt the given cpu times take into account the PARI/GP computations. As a > comparison, Magma takes 55s for that computation on my computer. > > The wall time is not very useful (my machine has a load of 3-4). It would be > more useful to have to cpu time used by the spawned processes, or simply the > total cpu time used by SAGE and those processes. > > Paul Zimmermann > > def FindGroupOrder(p,s): > K = GF(p) > v = K(4*s) > u = K(s^2-5) > x = u^3 > b = 4*x*v > a = (v-u)^3*(3*u+v) > A = a/b-2 > x = x/v^3 > b = x^3 + A*x^2 + x > E = EllipticCurve(K,[0,b*A,0,b^2,0]) > return factor(E.cardinality()) > > > > -- John Cremona --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
