On Mar 20, 2007, at 7:11 AM, DanK wrote:
> sage: v=1; w=1; x=1 #Berechnung von Vp,t noch ohne modulo q > sage: for i in range(1,((p-1)/2)+1): > ... v=z^i-z^(-i)%q > ... w=v^(i^expo) > ... x=(x*w)%q One serious problem is, that on the line > ... w=v^(i^expo) you are doing the modular arithmetic extremely inefficiently. For example, when i is 18, then i^expo = 104976, and even if v is as small as 2, then you are already dealing with numbers that are thousands of digits long, whereas all the modular arithmetic could be done mod q. Compare the following: sage: x = 100 sage: y = 1000000000000000000000000 sage: x^y % 241 (that should keep your computer busy for a while) but you can also get the result in the following way, sage: R = Integers(241) sage: R Ring of integers modulo 241 sage: x = 100 sage: y = 1000000000000000000000000 sage: R(x)^y 15 which is a little faster. > Traceback (most recent call last): > for i in range(1,((p-1)/2)+1): > File "/usr/local/sage/local/lib/python2.5/", line 3, in <module> > > RuntimeError Probably the reason you are getting this error is you are trying to compute an exponential (as I indicated above) which is making your machine run out of memory. David --~--~---------~--~----~------------~-------~--~----~ 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/ -~----------~----~----~----~------~----~------~--~---
