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Re: [Axiom-developer] severe (!) bug in normalize
From: |
Francois Maltey |
Subject: |
Re: [Axiom-developer] severe (!) bug in normalize |
Date: |
05 Dec 2006 21:18:20 +0100 |
User-agent: |
Gnus/5.09 (Gnus v5.9.0) Emacs/21.4 |
Dear Martin, and others...
> I just discovered a severe bug in normalize$EFSTRUC. It is probably the worst
> thing I found so far.
>
> with
>
> T :=t^(n^2)*(sqrt(1+t))^n
>
> normalize(T/eval(T, n=n-1))
>
> gives sqrt(t+1). sum$SUMFS uses this method to check whether a function is
> rational for Gosper, and thus returns completely false results, which are,
> however, difficult to detect.
>
> Waldek, am I right that you know normalize a little bit?
> If you do, PLEASE look into this, it is a real show stopper for me.
I'm testing some patchs in expr.spad.
On my today-version I get :
(64) -> T := t^(n^2)*sqrt(1+t)^n
2
n +-----+n
(64) t \|t + 1
Type: Expression Integer
(65) -> T/subst (T, n=n-1)
2n - 1 +-----+
(65) t \|t + 1
Type: Expression Integer
(68) -> normalize (T/eval (T, n=n-1))
+-----+ (2n - 1)log(t)
(68) \|t + 1 %e
Type: Expression Integer
Do you want this expr.spad ?
expr.spad
Description: a new expr.spad file
There are some buggy print inside.
I hope it shall work for you.
I also must change very few lines in others files.
If you want to compile and test it.
Francois
- [Axiom-developer] severe (!) bug in normalize, Martin Rubey, 2006/12/05
- Re: [Axiom-developer] severe (!) bug in normalize,
Francois Maltey <=
- [Axiom-developer] Re: severe (!) bug in normalize, Waldek Hebisch, 2006/12/05
- [Axiom-developer] Re: severe (!) bug in normalize, Martin Rubey, 2006/12/06
- [Axiom-developer] Re: severe (!) bug in normalize, Martin Rubey, 2006/12/06
- [Axiom-developer] Re: severe (!) bug in normalize, Waldek Hebisch, 2006/12/06
- [Axiom-developer] Re: severe (!) bug in normalize, Martin Rubey, 2006/12/06
- [Axiom-developer] Re: severe (!) bug in normalize, Waldek Hebisch, 2006/12/06
- [Axiom-developer] Re: severe (!) bug in normalize, Waldek Hebisch, 2006/12/06
- [Axiom-developer] Re: severe (!) bug in normalize, Martin Rubey, 2006/12/06