automatic differentiation and change expression ordering

[Christian Bauer]

Hi!

On Wed, Nov 05, 2003 at 09:47:48PM +0200, Andrius Kurtinaitis wrote:
> int main()
> {
>   symbol r("r");
>   ex der1  = mul( diff( intensity(r), r ), r ).hold();

Don't use hold() here.

>   ex deriv = der1.diff(r);
>   cout << deriv << endl;
>   return 0;
> }
> 
> I get the following output:
> D[0,0](intensity)(r)*r+D[0](intensity)(r)
> 
> But I would like to get something like this:
> 
> D[0]( D[0](intensity)(r)*r )(r)
> 
> Is it possible with ginac?

No. fderivative can only represent derivatives of symbolic functions, not
of general expressions.

> 2. What is the simplest way to change the order in multiplication so 
> that the differential operators print after all other terms:
> r*D[0,0](intensity)(r)
> instead of
> D[0,0](intensity)(r)*r

You'd have to rewrite the output routine of the 'mul' class to rearrange
the terms. This is possible in GiNaC 1.2 without modifying GiNaC itself,
but it is not a trivial task.

> Is there maybe some work done to output fderivative in latex style?

Suggestions are welcome. :)

Bye,
Christian

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