2009/9/2 Dan Drake <dr...@kaist.edu>: > On Tue, 01 Sep 2009 at 11:42PM -0700, Robert Bradshaw wrote: >> If we support the ! notation, we should either have x!! == (x!)! or, >> preferably, x!!..! be the multi factorial (not limiting ourselves to >> single and double). > > I study combinatorics, and I'm fine with *not* supporting ! notation. > Writing "factorial(x)" is obvious and unambiguous. If you want something > shorter, you can do "f = factorial". Then the mysterious and ambiguous > examples above turn into something obvious: f(f(5)) or whatever. We > already have "multifactorial" support: (5).multifactorial(2) equals 5 * > 3 * 1, and so on. > > I don't see anyone strongly demanding ! notation, so I say we drop the > idea. We have factorial() and .multifactorial(), they work perfectly > well, and the syntax for using them is the same as in the rest of Sage. > > Dan
To me at least writing 'factorial(n)' is a bit clumbersome, compared to what I would expect. Mathematica supports Plus[2,3] = 5 and Factorial[5] = 120 but I doubt I'd ever want to write 'Plus' or 'Factorial' out in full, which there are such commonly used symbols for this. But clearly Mathemaitca shows there is some ambiguity about how multiple exclamation marks are used. Dave --~--~---------~--~----~------------~-------~--~----~ 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 this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
