Re: [sage-support] Re: sage->nauty->directed graphs isomorphism vs. magma -- smth is very wrong

2014-03-04 Thread Tom Boothby
They do implement the same basic algorithm. However, Robert worked from McKay's paper describing the algorithm, which was approximately state-of-the-art when he wrote the paper (but of course, the community tends to eschew optimizations as superfluous to the math, so...). Also, nauty has some pret

[sage-support] Re: Different behaviour of "sage -gap" and "gap pexpect interface"

2014-03-04 Thread Simon King
Hi Volker, On 2014-03-04, Volker Braun wrote: > --=_Part_318_11599549.1393944350520 > Content-Type: text/plain; charset=UTF-8 > > Did you rebuild the cached workspace? I.e. "rm -rf ~/.sage/gap". If you > manually install a package in GAP then we can't know that a package was > added... Yes

[sage-support] Re: Different behaviour of "sage -gap" and "gap pexpect interface"

2014-03-04 Thread Volker Braun
Did you rebuild the cached workspace? I.e. "rm -rf ~/.sage/gap". If you manually install a package in GAP then we can't know that a package was added... On Monday, March 3, 2014 9:12:12 PM UTC, Simon King wrote: > > Hi! > > I thought that sage's pexpect interface to GAP just launches "sage -g

[sage-support] Semidirect product of PGL

2014-03-04 Thread sajith p
Hi, I would like to do semidirect product of PGL(3,4) with Z_2. The homomorphism phi: z_2 --> Aut(PGL(3,4) is defined as follows. phi(-1)(A) = (A^{-1})^t. That is A inverse transpose. If I can directly find the projective semilinear group P Gamma L(3,4) using sage, then it is very helpfull ht

[sage-support] Re: sage->nauty->directed graphs isomorphism vs. magma -- smth is very wrong

2014-03-04 Thread Dima Pasechnik
On 2014-03-03, Volker Braun wrote: > AFAIK both implement the same basic algorithm. My guess is that nauty > quickly realizes that it has a huge problem and starts constructing graph > invariants in an attempt to answer it to the negative. If you were to > compare two graphs that are actually i