[GiNaC-list] GiNaC-list Digest, Vol 93, Issue 4

[Vladimir V. Kisil]

>>>>> On Mon, 30 Sep 2013 17:19:40 +0200, Gunnar Birke <gunnar.birke at online.de> said:

    GB> I can have an expression GiNaC::ex f, which contains something
    GB> like 3*x+2 where x is a symbol. So far so good, but how can I
    GB> handle things like f(2)?

    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. 
-- 
Vladimir V. Kisil     email: kisilv at maths.leeds.ac.uk
                        www: http://www.maths.leeds.ac.uk/~kisilv/
Book: Geometry of Mobius Transformations
http://www.worldscientific.com/worldscibooks/10.1142/p835