[GiNaC-list] GiNaC-list Digest, Vol 93, Issue 4
Gunnar Birke
gunnar.birke at online.de
Mon Sep 30 17:50:07 CEST 2013
On 30.09.2013 17:32, Vladimir V. Kisil wrote:
> Let f be declared as GiNaC::ex and x be GiNaC::realsymbol. At some
> point a user may do an assignment f=3*x+2. If later he need the value
> which you denote by f(2), you need to return him f.subs(x==2). I
> cannot see a reason why you need to declare f as GiNaC::function,
> which shall not be confused with mathematical functions as maps X -> Y.
But what if I have multiple functions, for example f(x) and g(x) and
some expression e that looks like f(2) + g(5) ... . Calling e.subs(x==2)
would bring great trouble. How can I distinguish between the x in f(x) =
3*x+2 and the x in g(x) = 1/2*x-4, for example.
Of course I can imagine ways to make this work, but I don't like to
reinvent the wheel to much.
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