I would just make sure that the unpickling old matrices still works. --Mike --Mike
On Tue, May 21, 2013 at 2:02 PM, Jean-Pierre Flori <jpfl...@gmail.com> wrote: > > > On Tuesday, May 21, 2013 2:47:07 PM UTC+2, Martin Albrecht wrote: >> >> Sounds like a good idea to me. > > Sounds good to me too. >> >> >> On Tuesday 21 May 2013, Volker Braun wrote: >> > Reposted at the top to increase visiblitiy (see >> > https://groups.google.com/d/msg/sage-devel/5PdRIUic2Es/l0yDYLG_8qIJ) >> > >> > The sage matrices use unsigned long for the mod_int datatype. This does >> > not >> > fit into a (signed) python int, so whenever it reaches Python (assigning >> > to >> > a Python variable, or passing as an argument to a non-cdef function) it >> > gets converted to a Python arbitrary-precision integer. This wastes >> > quite a >> > bit of time when creating it and gets worse once you start doing >> > arithmetic: >> > >> > -------------------------------------- >> > ctypedef unsigned long mod_int # this is how we define it >> > >> > cpdef caster_slow(): >> > cdef int i >> > foo = None >> > for i in range(10000000): >> > foo = <mod_int>(1.0) >> > >> > cpdef caster_fast(): >> > cdef int i >> > foo = None >> > for i in range(10000000): >> > foo = <int>(1.0) >> > -------------------------------------- >> > >> > Then we get >> > >> > sage: timeit('caster_slow()') >> > 5 loops, best of 3: 137 ms per loop >> > sage: timeit('caster_fast()') >> > 25 loops, best of 3: 34.4 ms per loop >> > >> > Should we just switch to (signed) long? This wastes one bit (factor of >> > 2) >> > of maximum modulus length, but at least for now we define MAX_MODULUS = >> > 2**23 so this wouldn't be an issue. >> >> Cheers, >> Martin >> >> -- >> name: Martin Albrecht >> _pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99 >> _otr: 47F43D1A 5D68C36F 468BAEBA 640E8856 D7951CCF >> _www: http://martinralbrecht.wordpress.com/ >> _jab: martinr...@jabber.ccc.de > > -- > 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 http://groups.google.com/group/sage-devel?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > -- 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 http://groups.google.com/group/sage-devel?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
