On Sat, Aug 25, 2012 at 9:52 AM, Chris Smith <[email protected]> wrote: > On Sat, Aug 25, 2012 at 4:12 PM, Tom Bachmann <[email protected]> wrote: >> >> >> On 25.08.2012 10:40, Chris Smith wrote: >>>>> >>>>> We have that, but I think it uses the unconventional R to L rather >>>>> than L to R convention: >>>>> >>>>>>>> >>> p=Permutation >>>>>>>> >>>>>>>> p([[1,2],[0],[3]])*p([[2,3],[0],[1]] >>>>> >>>>> ... ) >>>>> Permutation([0, 2, 3, 1]) >>>>>>>> >>>>>>>> _.cyclic_form >>>>> >>>>> [[1, 2, 3], [0]] >>>>> >>>>> >>>>> http://en.wikipedia.org/wiki/Cycle_notation says that the answer of >>>>> the above should be (132) not (123) (which is what SymPy gives when >>>>> the order of multiplication is reversed). >>>>> >>>> >>>> Actually, that is very bad I think. If it doesn't follow standard >>>> conventions and notations, >>>> people will not use it. >>> >>> >>> I've got this fixed but there are lots of failures in other areas of >>> combinatorics so i might as well close this for now. I (as you) >>> consider this a show stopper. >>> >> >> Huh? At least in my courses, cycles where just a short-hand notation for >> permutations, and where composed in precisely the way this code does. I know >> there are arguments for composing on the right, but I don't think this is >> universally done (or even by a majority). I don't know about specialised >> fields, though (e.g. there is a famous crystallography book composing on the >> right, but even in its field it is an exception, not the rule). > > > It's as it was, using L to R but I added a reverse option so one can > go R to L if desired.
Can you please explain, in terms a complete idiot like me can understand, what steps I go through to test your code? I have access to macs (running lion) and linux (running ubuntu 12.04), both with git installed. Someone told me once with Aleksander M's branches but I've forgotten the steps and am not sure how well the instructions translate to your patches. > > -- > You received this message because you are subscribed to the Google Groups > "sympy" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/sympy?hl=en. > -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
