Hi all, It seems none of the current substitute methods for symbolic expressions works for the argument of the derivative operator.
In computing functional derivative, I need to vary a functional. For example, in sage-3.4 I can do as follows ------- sage: f(x) = function('f',x) sage: df(x) = function('df',x) sage: g = f(x).diff(x) sage: g diff(f(x), x, 1) sage: g.subs_expr(f(x)==f(x)+df(x)) diff(f(x) + df(x), x, 1) ------- In new symbolics, if I do the same I get -------- sage: g D[0](f)(x) sage: g.subs_expr(f(x)==f(x)+df(x)) D[0](f)(x) --------- Is there a way to do this in new symbolics? It seems to be a road block in implementing calculus of variations in new symbolics. Thanks, Golam --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send 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 -~----------~----~----~----~------~----~------~--~---