[GiNaC-list] Symbolic Differentiation

[Diego Ariel Hollmann]

Hello, I've seen a thread last month from Martin Ettl, and I'm having the
same problem but the solution proposed by Jens Volling does not work for me.

I need to derive expressions with variables that depend on others, for
example: x(t)^2+sin(y(t)). I need to derive with respect to variable t.

The solution proposed by Jens was:

DECLARE_FUNCTION_1P(a)
DECLARE_FUNCTION_1P(b)
REGISTER_FUNCTION(a, dummy())
REGISTER_FUNCTION(b, dummy())

int main()
{
	symbol t("t");

	ex expr = a(t) * b(t);

	cout << expr << endl;
	cout << expr.diff(t,1) << endl;

	return 0;
}


This does not work with all kind of expressions, for example, with the one
I wrote before... if I use this solution with: ex expr = a(t)^2 + sin(b(t))
it throws an error with the operator "^".

Any idea how can I do this king of derivations?

Thank you in advance!
Diego H.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.cebix.net/pipermail/ginac-list/attachments/20120821/e808f98d/attachment.html>