axiom-math
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## Re: [Axiom-math] About rewrited expressions for power, log, exp and so.

 From: Francois Maltey Subject: Re: [Axiom-math] About rewrited expressions for power, log, exp and so. Date: 30 Nov 2006 19:04:28 +0100 User-agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.4

```Hello Martin,

> > But then how can I test if standard exemples of axiom continue to be right
> > with a new elemntry.spad ?
>
> Well, I'm still hoping for a unit testing package. But in fact, I
> wouldn't mind if some "standard example" stops working, but in
> exchange a dozen others start working.

So the first thing is to write a such list of exemples.
I'll begin soon.

> My advice is: look at MuPaD and see how things are done there. I
> think they got it right.

Mupad was the finest one for that.
I'll take it again for testing and debugging axiom...

And mupad had 2 features which aren't (yet) in axiom expressions :

1/ The assume command :
assume (a>1) ; limit (a^x, x=%plusInfinity)            --> %plusInfinity
assume (a=1) ; limit (a^x, x=%plusInfinity)            --> 1
assume (a<1 and -1<a) ; limit (a^x, x=%plusInfinity)   --> 0
assume (a<-1) ; limit (a^x, x=%plusInfinity)           --> "failed"

2/ the piecewise command :
solve (a*(a-1)*x=a, x)
x = 1/(a-1)   if a in C \setminus {0, 1}
x in C        if a=0
x in emptyset if a=1

> Apart from that, implement many good computable domains.

You advise me to write a new domain,
not to correct (with a pamphlet file) the historic files ?

What method do you advice ?

I copy the efstruct.spad in a new directory, modify it, comment it,
compile it and load it at the beginning of the session.

I will complete my expand / rewrite / combine package
in order to be coherent too.