On Wednesday, August 17, 2016 at 3:25:31 PM UTC-7, Bill Page wrote: > > > It turns out that a solution is now "hidden away" in plain sight: > > https://trac.sagemath.org/ticket/18640 > > http://sagemanifolds.obspm.fr/doc/18640/reference/manifolds/sage/manifolds/utilities.html > > > And also note the warning that's in the documentation there already: (*) """ Note that D[1](g)(x, f(x,y)) is rendered as d(g)/d(f(x, y)). """ How is that unambiguous?
Maple internally uses the same representation for derivatives as Pynac does (as far as I can tell) and it has a reasonable heuristic: The expression: D[i](f)(x1,...,xn) can be rendered as (df/dxi)(x1,...,xn) if x1,...,xn are *distinct* pure variables or if n=1. Otherwise, render it D[i](f)(x1,...,xn). This is something that the standard expression renderer could do. It just requires a bit more work because "function application rendering" would need to inspect its function for the presence of an FDerivativeOperator. The situation for topological manifolds is slightly different, because expressions there live in the context of a chart, where a specific correspondence between variable name and parameter position has been imposed. That makes it plausible that in the context of charts, one can get away with possible ambiguities a little easier. That said, I find it hard to not consider the example (*) an outright bug. -- 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
