Discussion related to cado-nfs

[Paul Leyland <paul.leyland@gmail.com>]

On 13/04/2020 12:41, paul zimmermann wrote:
>        Dear Adolfo,
>
>> Dear Paul,
>>
>> Yes! Thank you really very much!!!
>>
>> Just one more question: if I have to factorize a small number such as
>> 576460752303423487, what should I do to have CADO-NFS working?
>>
>> Thanking you in advance, I remain
>>
>> Sincerely yours,
>> Adolfo
> CADO-NFS is not designed to factor such small numbers. You could use Sage
> instead (sagemath.org):
>
> ┌────────────────────────────────────────────────────────────────────┐
> │ SageMath version 8.6, Release Date: 2019-01-15                     │
> │ Using Python 2.7.15. Type "help()" for help.                       │
> └────────────────────────────────────────────────────────────────────┘
> sage: factor(576460752303423487)
> 179951 * 3203431780337
>
> or Pari/GP (https://pari.math.u-bordeaux.fr/):
>
>                   GP/PARI CALCULATOR Version 2.7.5 (released)
>           amd64 running linux (x86-64/GMP-6.0.0 kernel) 64-bit version
>   compiled: Nov 10 2015, gcc version 5.2.1 20151028 (Ubuntu 
> 5.2.1-23ubuntu1) 
>                            threading engine: pthread
>                  (readline v6.3 enabled, extended help enabled)
>
>                      Copyright (C) 2000-2015 The PARI Group
>
> ? factorint(576460752303423487)
> %1 = 
> [       179951 1]
>
> [3203431780337 1]
>
> Hope this helps,
> Paul

Or even just plain old Unix factor(1), which is much lighter-weight
alternative to the pair above:

pcl@thoth:~$ time factor 576460752303423487
576460752303423487: 179951 3203431780337

real    0m0.001s
user    0m0.001s
sys    0m0.000s

----

The other Paul