Karim BELABAS on Tue, 7 Jan 2003 21:17:58 +0100 (MET)

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

Re: gp: gcd(0) error message unhelpful

On Tue, 7 Jan 2003, Michael Somos wrote:
> I suppose I could just use "gdb" and get a backtrace that way if all else
> fails.

Btw, you can use break loops for this purpose:

(21:14) gp > i = 0; 1/i; i^2
  ***   division by zero in gdiv, gdivgs or ginv
  ***   Break loop (type 'break' or Control-d to go back to GP): i=0;1/i;i^2
The default error message is distinctly unhelpful, but the break loop tells
me where where the problem occured [ and I can also inspect the local
variables at this point ]

At the end of my initialization file, I set the default trap handler to
enable this behaviour [ 'trap()'; I agree the interface is not nice, but at
least it is documented ]


Karim Belabas                    Tel: (+33) (0)1 69 15 57 48
Dép. de Mathématiques, Bât. 425  Fax: (+33) (0)1 69 15 60 19
Université Paris-Sud             Email: Karim.Belabas@math.u-psud.fr
F-91405 Orsay (France)           http://www.math.u-psud.fr/~belabas/
PARI/GP Home Page: http://www.parigp-home.de/