Re: couldn't find a suitable name for a tempfile (COMB)

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

[Ottavio Rizzo:]
> I'm computing root numbers for a lot of elliptic curves, and after
> some hundred thousands computations, gp (Version 2.0.13) stops with
> the following  error message: what does it mean?
> 
>   ***   couldn't find a suitable name for a tempfile (COMB).

PARI tried to build a name for a temporary file (needed by MPQS in this
case) to be placed in the default temp directory (first writable directory
in the following list $GPTMPDIR, $TMPDIR, /var/tmp, /tmp).

This name is built with a supplied prefix (COMB), where you append user and
process id. [Under DOS, filename format is pretty restricted and id's are
irrelevant hence the format is different but I assume you're using the Unix
version].

If a file by that name already exists, PARI appends a letter ("a" to "z").
If this also fails, one gets the above message... Right now (for debugging
purposes: mpqs is a relatively new addition), these particular tempfiles are
not cleaned up when an error is raised, the computation is interrupted, etc.

Hence if your system is very stable (/var/tmp hardly ever cleaned up on
reboot), or you are using a private tempdir which you don't clean up from
times to times, tempfiles may accumulate. You should check your temp
directory (from the list above) and remove all obsolete tempfiles here. 

If there aren't zillions of COMB* files in there, I'd appreciate more
details.

  Karim.
--
Karim Belabas                    email: Karim.Belabas@math.u-psud.fr
Dep. de Mathematiques, Bat. 425
Universite Paris-Sud             Tel: (00 33) 1 69 15 57 48
F-91405 Orsay (France)           Fax: (00 33) 1 69 15 60 19
--
PARI/GP Home Page: http://hasse.mathematik.tu-muenchen.de/ntsw/pari/