Hi all, Thanks for your answers. There are a few things that I now understand, but i'm still confused. One crucial mistake I made was, as I see now thanks to Ralf's message, to believe that numpy.int meant "C int": no, it means python int ! For C ints, use numpy.int32 (or 64). In fact :
sage: numpy.int(2) ^ numpy.int(32) 4294967296 sage: numpy.int(2) ^ numpy.int(64) 18446744073709551616L #notice the L, typical of python ints sage: numpy.int32(2) ^ numpy.int32(32) /Applications/SageMath/src/bin/sage-ipython:1: RuntimeWarning: overflow encountered in int_scalars #!/usr/bin/env python 0 All as expected. And to answer Simon's interrogation, if I'm correct a python int is actually arbitrary precision (and it prints with an L when above 2^64), but it's slower than ZZ. It's not a C int. However, i've been playing with Simon's code for testing (nice idea!), and i'm still puzzled: sage: %time testfunc(ZZ(1234123), ZZ(1234123), operator.add) CPU times: user 69.3 ms, sys: 787 µs, total: 70.1 ms Wall time: 70.8 ms sage: %time testfunc(int(1234123), int(1234123), operator.add) CPU times: user 42.3 ms, sys: 631 µs, total: 42.9 ms Wall time: 43.5 ms sage: %time testfunc(numpy.int(1234123), numpy.int(1234123), operator.add) CPU times: user 44 ms, sys: 538 µs, total: 44.5 ms Wall time: 45 ms sage: %time testfunc(numpy.int32(1234123), numpy.int32(1234123), operator. add) CPU times: user 74.2 ms, sys: 822 µs, total: 75 ms Wall time: 77.7 ms So ZZ is slightly slower than python int = numpy.int, which is already weird since the arbitrary precision integers of ZZ are meant to faster than those of python. But even more bizarre is the fact that numpy.int32 gives the slowest performance! i'm guessing that the operator.add includes overhead when asking numpy to add its ints. Question: Is there a way of using very fast C integers within Sage, without using Cython? (the latter because the answer is meant to be understandable by beginners). If I figure this out, I guess the analogous question with floats will be answered, too. Thanks ! Pierre -- 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.
