Karim BELABAS on Thu, 3 Oct 2002 18:39:40 +0200 (MEST)

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

Re: MPQS not cleaning up files

On Wed, 2 Oct 2002, Michael Somos wrote:
>     For several months I had been puzzled by strange files which
> appeared in my "/tmp" directory on rare occasions and I had not
> even known which program was responsible. Here is an example :
> -rw-------    1 somos    somos        7224 Jul 21 15:04 FNEW.614.15591
> -rw-------    1 somos    somos      220962 Jul 21 15:04 FREL.614.15591
> -rw-------    1 somos    somos        8055 Jul 21 15:04 LPNEW.614.15591
> -rw-------    1 somos    somos      192510 Jul 21 15:04 LPREL.614.15591
> After a simple google search (don't know why I didn't try that
> right away) I discovered that these are from 'gp' in the 'mpqs.c'
> module. Moreover, this is totally undocumented. I had no idea
> that 'gp' was using these temp files. Probably, they appear when
> I interrupted a long factorization. Shalom, Michael

They appear whenever the MPQS module is called by the integer factoring
engine (for relatively large numbers with no "small" prime divisors, then).

On normal termination, the files are deleted. On abnormal termination,
including user interrupt, they are left over. I believe this was intended, in
order to

(1) debug faulty behaviour

(2) restart interrupted jobs in case of system shutdown: it is not uncommon to
let MPQS run for a few months.

It has been a long time since a bug was reported in this module
[ unfortunately, development stopped at about the same time ]. So (1) is
probably no more a concern. (2) still is, although with the current state of
the interface, it would be difficult to recover an interrupted job (this is
not documented in any case).

It is easy to change this behaviour. It is probably desirable (I would not
object to it, at least until a decent interface to continue interrupted
computations is developped). Maybe we can discuss this on pari-dev ? [Cc-ed].


Karim Belabas                    Tel: (+33) (0)1 69 15 57 48
Dép. de Mathematiques, Bat. 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/