Am 26 Nov 2005 um 22:25 hat Alasdair McAndrew geschrieben:
> Hi Volker,
>
> I just checked the ifactor.lisp code, and it works very well: it
> computed the two large prime factors of 2^128+1 in a little over three
> and a half hours. It factors 2^64+1 and 2^67-1 almost immediately.
>
> I've written for my own purposes some Maxima code for modular
> exponentiation, inversion, and extended euclidean algorithm, which all
> seems to work fine.
>
> The problem you quote about the results of gcdex is that the algorithm
> works on polynomials, not integers. For example:
>
> gcdex(12345,56789,1);
> [-9/2743,2,2743,1]
>
> which is not very useful. My own function does better:
>
> igcdex(12345,56789);
> [1,-17039,3704]
>
Alasdair,
it seems that i should be the prefix for integer functions. OK to me.
You mention your Maxima code. Did you write it on Maxima or on Lisp level? We only
get fast code, if we have it on Lisp level.
Please let me have a look at your code.
Cheers
Volker