Re: polredabs() observation

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

On Fri, 31 Jan 2003, Igor Schein wrote:

> On Tue, Jan 28, 2003 at 10:09:08AM -0500, Igor Schein wrote:
>> polredabs() on the following polynomial is much slower in latest CVS compared to stable:
>>
>> x^16-224*x^14+19520*x^12-843488*x^10+19172700*x^8-223732800*x^6+1177835136*x^4-1779647552*x^2+171662404
>
> Actually, here's the very recent change that made polredabs()
> considerably slower in many cases:
>
> \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
> revision 1.627
> date: 2003/01/04 19:00:43;  author: karim;  state: Exp;  lines: +2 -0
> 48- simplified fincke_pohst() [don't recompute gram_matrix]
> \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
>
> And here's a smaller yet even more drastic example:
>
> polredabs(x^4+51976*x^3+837697192*x^2+4716826989696*x+5560701377110272);

Typo: the smallvectors() bound was the square of what it should have been...
I was confused by the terse comment [ due to me, from code
reverse-engineering ] at the header of sqred1(), and didn't check which
"Cholesky form" it was about. It turned out it was not the standard one:-(.

Both fixed.

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