On Sun, Apr 12, 2015 at 9:58 AM, Terry Reedy <tjre...@udel.edu> wrote: > I believe longobject effectively represents ints in base 2**15 or 2**30 (or > 31?) for 32 and 64 bit machines, so that products of 'digits' fit in a > single machine word. (I am not sure if the increased size for 64 bit > machines was implemented or not.) > >> Performance doesn't seem to change in Py3 as >> the numbers get bigger: > > I suspect the effect is more dramatic with multiplication.
Sorry, sloppy language. Of course larger numbers will be a bit slower, but there's no stark change at the edge of the machine word. The performance loss from going from one limb to two will be comparable to the loss from going from five to six, where it's already well past machine integer. In Py2, there's a significant difference between "int" performance and "long" performance (regardless of the actual size of integer involved), but Py3 is more consistent. It's a missed optimization at worst, but the upshot is that a Python programmer doesn't need to think about integer sizes at all. ChrisA -- https://mail.python.org/mailman/listinfo/python-list
