Re: [sage-devel] Digest for sage-devel@googlegroups.com - 2 updates in 1 topic

2014-04-05 Thread Tom Coates
t; > -- > 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] Re: matrix multiplication over ZZ sometimes gives incorrect results

2011-05-21 Thread Tom Coates
On May 21, 8:55 am, Maarten Derickx wrote: > Good you found this. I already noticed that the modular symbols code > some times gave me a different awnser then before, but I couldn't > reproduce this so I guess this is the underlying reason. That is very plausible: it also causes occasional and

[sage-devel] matrix multiplication over ZZ sometimes gives incorrect results

2011-05-20 Thread Tom Coates
code in sage/ext/multi_modular.pyx is not handling a corner case properly. The relevant routine (mpz_crt_vec_tail) involves both Cython and GMP, so if someone with Cython and/or GMP experience could give me a hand debugging it then I would be very grateful. This is trac #11358. Yours, Tom -

[sage-devel] Re: factorial() and gamma()

2010-06-16 Thread Tom Coates
On 16 June, 07:48, rjf wrote: > By your reasoning, and for other domains we would have the following > behavior: > > 1-2  --> error.    1 and 2 are both positive integers. In order to > provide the answer -1, one must > expand the domain to include negative integers. > > 1 / 2  -->   error..  

[sage-devel] factorial() and gamma()

2010-06-15 Thread Tom Coates
As ddrake pointed out in Trac #9248, even when x is in the symbolic ring, factorial(x) is not simply calling gamma(x+1): sage: x=I; factorial(x) 0.498015668118356 - 0.154949828301811*I sage: gamma(x+1) gamma(I + 1) So something strange is going on. I think that the first example here is probabl

[sage-devel] Re: question about pattern matching in pynac

2010-06-15 Thread Tom Coates
> My vote is to have factorial(n) = n(n-1)...2.1 whenever n is integer. > > Cheers, > > Florent We certainly need to allow for symbolic input too, so that Sage can simplify expressions involving factorials and binomial coefficients such as: sage: var('k,n') (k, n) sage: f = factorial(k)*factoria

[sage-devel] Re: question about pattern matching in pynac

2010-06-15 Thread Tom Coates
I will change the documentation of factorial() to make this clear. Best, Tom On 15 June, 01:14, David Kirkby wrote: > On 15 June 2010 05:21, Tom Coates wrote: > > > > > > > Dear sage-devel, > > > I believe that the following: > > > sage: gamma(x).ful

[sage-devel] question about pattern matching in pynac

2010-06-14 Thread Tom Coates
ching functionality in pynac handle this? Or is there another way to do it? Best, Tom --- Tom Coates Royal Society University Research Fellow Reader in Pure Mathematics Imperial College London -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, se

[sage-devel] applying full_simplify() to gamma functions causes an error

2010-06-14 Thread Tom Coates
): http://trac.sagemath.org/sage_trac/ticket/9240 and uploaded a patch to fix it. Best, Tom --- Tom Coates Royal Society University Research Fellow Reader in Pure Mathematics Imperial College London -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this

[sage-devel] Taylor expansion of gamma functions is broken

2010-06-11 Thread Tom Coates
h.org/sage_trac/ticket/9217 and uploaded a patch to fix it. Best, Tom --- Tom Coates Royal Society University Research Fellow Reader in Pure Mathematics Imperial College London -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to

[sage-devel] Re: Multivariate polynomial multiplication over Z

2010-05-17 Thread Tom Coates
It turns out that for my problem it suffices to compute the polynomials 1, f, f^2, ..., f^K modulo N for some large but known number N, so I suspect that it may be faster to work modulo p for various primes p and then use the Chinese Remainder Theorem. How large, roughly speaking, can I take my

[sage-devel] Re: Multivariate polynomial multiplication over Z

2010-05-15 Thread Tom Coates
On May 15, 9:03 pm, William Stein wrote: > 1. On what hardware? This was on 64 bit GNU/Linux (Fedora release 12) running on a dual processor machine with two Intel Core 2 CPUs (each 2.4GHz, 4Gb cache). I have included the contents of /proc/cpuinfo at the bottom of this reply. > 2. Can you po

[sage-devel] Re: Multivariate polynomial multiplication over Z

2010-05-15 Thread Tom Coates
Thank you (everyone!) for the many extremely helpful comments and links. Recall that I need to compute 1, f, f^2, ..., f^K for f in ZZ[x,y,z] and K known but large. (In fact I only need certain coefficients of the f^i, but this does not seem to help very much.) I have implemented the most naiv

[sage-devel] Re: sage 4.3.5 won't build on Red Hat Enterprise Linux 5.4: File exists: '/usr/local_machine/sage-4.3.5/local//lib/python/site-packages//sage/structure'

2010-04-13 Thread Tom Coates
Dear Georg, Many thanks! Running "make" again solved the problem. I updated the trac ticket. Best, Tom -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit thi