Setting a runtime limit for msieve

[burrobert]

Is there a way of setting a runtime limit for msieve? I would like msieve_run to work at factoring a number for a set time and to then either return the result if it finds one within that time or send an appropriate message if it does not find one within the time limit.

[jasonp]

Using the -d switch for the demo binary will trigger an interrupt after a fixed number of seconds.

[burrobert]

Thanks Jason. That looks promising. I'll try to adapt it to my situation.

[VBCurtis]

Originally Posted by burrobert

Is there a way of setting a runtime limit for msieve? I would like msieve_run to work at factoring a number for a set time and to then either return the result if it finds one within that time or send an appropriate message if it does not find one within the time limit.

Msieve, when it runs the quadratic sieve or NFS, finds factors in an amount of time determined largely by the size of the number to be factored; it is not an ECM-style "maybe it finds them quickly, maybe slowly" sort of process.

The time to factor roughly doubles every 5 digits for GNFS. You can run just a couple of full factorizations to measure the speed of your setup and get a very good idea of how long msieve will take on any number (say, under 150 digits) you feed it. Are you sure you want to slap a deadline on the program, when you may be 80% complete with the factorization and could have known that without wasting the runtime you spend?

[burrobert]

Thanks for your reply Curtis. I am using msieve for instructional purposes where it is not too important that a result is found. It is more important for the user to know that the program will terminate after a set time.