[GiNaC-list] implicit differentiation
Felipe Bordeu
felipe.bordeu at ec-nantes.fr
Wed Jun 2 15:16:18 CEST 2010
Hi everyone,
I created a class for GiNaC to treat implicit differentiation, here is
an example:
symbol x = get_symbol("x"); ----> I use
a factory
ex A = dersymbol("A").dependent_of(x); -----> my new class,
and I tell that is dependent of x
ex dAdx = A.diff(x);
cout << A << endl; ----->
"A(x)"
cout << "dA/dx : " << dAdx ; -----> "A(x)_1x"
cout << "d2A/dx2 : " << dAdx.diff(x) ; -----> "A(x)_2x"
cout << "dA/dy : " << A.diff(get_symbol("y")) ; -----> "0"
Inside dersymbol I store the dependents variables and the degree of the
differentiation.
now my problem is that I what to make the substitution of A to something
else, like x^2:
cout << "dA/dx with A=x^2 is : " << dAdx.subs(A==pow(x,2)) << endl;
(I know that the previous line is not correct)
to get something like : "2*x"
Any ideas??
Thanks
(first time in this mailing list)
Felipe
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