Karim Belabas on Mon, 03 Jun 2013 14:15:41 +0200

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: weird error in thueinit

* Max Alekseyev [2013-06-03 13:49]:
> On Mon, Jun 3, 2013 at 7:17 AM, Bill Allombert
> <Bill.Allombert@math.u-bordeaux1.fr> wrote:
> > I suggest you add
> > y;
> > as the first line of your script.
> Wow. It seemed to help.
> How this magic works?

This is a bug. When the main variable is "x", the nfroots() call
requires a new variable, which is selected to be "y" for debugging
purposes ( it's easier to read y^2 + 2 than <#123879>^2 + 2 when you run
into a later error or under a debugger... )

For some reason, the "y" variable already exists in your session
(it springs into existence when you use the "y" name); and for some 
reason, it was not created in the "proper" way and its content is
invalid at the time nfroots() tries to access it. Then we are dead.

I'm trying to understand how we reach this inconsistent state . :-)



P.S. I couldn't reproduce it yesterday because I use "y" myself in files
loaded by my gprc and never reached the inconsistent state. After Bill's hint,
I tried 'gp -f' and I can see it now.

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/
F-33405 Talence (France)       http://pari.math.u-bordeaux1.fr/  [PARI/GP]