[GiNaC-devel] removing the evil

[Alexei Sheplyakov]

On Tue, Jul 15, 2008 at 10:51:18AM +0200, Jens Vollinga wrote:
> Dear Alexei,
> 
> Alexei Sheplyakov schrieb:
> > 1. One can compare expressions in a natural way (with operator==,
> > operator==, etc) instead of GiNaC-specific is_equal().
> > 2. (a consequence of 1) No bugs like this:
> > 3. (a consequence of 1) STL containers and algorithms "just work" with
> > GiNaC classes.
> 
> okay, so far the advantages. I like them. But then, how would one write 
> the equalities to be given to solve(),

What about associative arrays? I.e.

exmap eqns;
eqns[a*x + b*y] = 5;
eqns[c*x + d*y] = 7;
exvector vars = boost::list_of(x)(y);
exmap result = solve(eqns, vars);

> subs(), ...?

This one is even more simple, because subs() already accepts an exmap.

> series(),

Just pass 2 arguments (the variable and the expansion point).

> Also, the answers returned by GiNaC like x==0 need to be given differently.

I think an exmap is a natural form for such answers.

Best regards,
	Alexei
 
-- 
All science is either physics or stamp collecting.

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