Re: weird error in thueinit

[Karim Belabas <Karim.Belabas@math.u-bordeaux1.fr>]

* Max Alekseyev [2013-06-02 13:31]:
> In my lengthy computations involving many thueinit() / thue() calls, I
> suddenly get the following error:
> 
>   *** thueinit: incorrect priority in nfroots: variable x >= x
> 
> in the call "thueinit(p)" with apperently innocent p = -29*x^4 +
> 184*x^3 - 294*x^2 + 184*x - 29.
> Right after this, calling thueinit(p) causes the same error, while
> explicit calling thueinit(-29*x^4 + 184*x^3 - 294*x^2 + 184*x - 29)
> works fine.

This is apparently generated when calling 
  thueinit(t_POL with automorphisms)
  -> bnfinit
  -> nfroots (to compute automorphisms in order to speed up bnfinit)

The "incorrect priority" is either 
1) a programming mistake on your side. Try to 

  - replace thueinit(p) by thueinit(simplify(p))

  - add write("some_logfile", getrand()) statements at various places
    Maybe resetting the random seed to this know value will help
    reproduce the problem.

2) the result of internal data corruption somewhere, which will be very
hard to track down unless you can supply a script that generates the
problem from scratch. Can you experiment and try to generate such a script ?

Cheers,

    K.B.
--
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux1.fr/~kbelabas/
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