Re: polredabs() behavior change

[Karim BELABAS <Karim.Belabas@math.u-psud.fr>]

On Thu, 12 Dec 2002, Igor Schein wrote:
> revision 1.111
> date: 2002/10/25 16:45:49;  author: karim;  state: Exp;  lines: +2 -2
> reduce number of stored elements in smallvector part of polredabs()
>
> Before this change:
>
> ? #polredabs(x^32-126*x^28-252*x^26+6017*x^24+33228*x^22+31878*x^20-119124*x^18-119820*x^16+228168*x^14+90738*x^12-251316*x^10+119633*x^8-15156*x^6+1278*x^4+36*x^2+1,4)
> 8
>
> After:
>
> ? #polredabs(x^32-126*x^28-252*x^26+6017*x^24+33228*x^22+31878*x^20-119124*x^18-119820*x^16+228168*x^14+90738*x^12-251316*x^10+119633*x^8-15156*x^6+1278*x^4+36*x^2+1,4)
> 1
>
> Was it done on purpose, and if so, what's the motivation?

Main goal: have faster smallvector, using much less stack space.

Side goal: exhibit hidden bugs in the implementations.

You found one (preexisting) problem: when there are too many small vectors
(as in your SD(5) example), we have to forget a number of them. But we forgot
too many.

Should be fixed now. Routine becomes slower, unfortunately; but I don't see
how it can be helped.

    Karim.
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Karim Belabas                    Tel: (+33) (0)1 69 15 57 48
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