On Thu, Jun 5, 2008 at 12:23 PM, Gonzalo Tornaria wrote: > On Thu, Jun 5, 2008 at 1:47 AM, William Stein wrote: >> ... How are you going to make, at >> runtime, new classes for each of Z/nZ say, for 1 <= n < 10^5, >> i.e., something like this in Sage: >> >> v = [Integers(n) for n in range(1,10^5)] >> >> I do not think it is possible to concisely create a hundred thousand >> separate Python classes like that. > ... > WRT your example: > > sage: def classinteger(m): > ... class A: > ... def __init__(self, n): > ... self.__n = n % m > ... def __repr__(self): > ... return "%d mod %d" % (self.__n, m) > ... A.__name__ = "classintegers mod %d" % m > ... return A > sage: classinteger(5)(3) > 3 mod 5 > sage: time v = [classinteger(n) for n in range(1,10^5)] > CPU time: 3.64 s, Wall time: 4.14 s > sage: time w = [Integers(n) for n in range(1,10^5)] > CPU time: 15.75 s, Wall time: 16.21 s > sage: v[1256](34251235) > 499 mod 1257 > ...
Excellent example. Thank you! > I was going to say that using classes built at runtime like this > was fine but not a good option for performance reasons, but the > example above shows the overhead of python class creation time > is not so significant. > Agreed. Python can treat types as fully first class objects. I think this strongly supports William's initial decision to choose Python as the basis for a new computer algebra system comparable to Magma and Axiom. Regards, Bill Page. --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@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-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
