question on possible factor() function for gmp
paul zimmermann
Paul.Zimmermann at inria.fr
Thu Jul 5 21:25:57 UTC 2018
Dear Randall,
> Date: Thu, 05 Jul 2018 10:39:53 -0700
> From: logical american <website.reader3 at gmail.com>
>
> Has someone put together a function for gmp called factor(n) where n is
> integer? (output is a list of factors and their powers)
>
> I did play around with the Pollard method but when I was working with
> 30-40 digit numbers to factor, GP Pari was always faster than gmp in
> this region.
>
> I understand that a general purpose program will shift algorithm
> according to the size of the number, such as the general number field
> sieve, when we're around 100 digits or so, but I would like to see some
> speed in the region of 20-80 digits.
>
> Thank you for responding.
>
> - Randall
you might try GMP-ECM, whose library provides a function ecm_factor:
int ecm_factor (mpz_t maybe_factor, mpz_t input_n, double B1, ecm_params params);
It will only find one factor at a time (when successful) but it is easy
to write a wrapper around it.
Paul Zimmermann
More information about the gmp-discuss
mailing list