Bill Allombert on Mon, 11 Apr 2011 19:32:08 +0200


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Re: int array to poly (libpari)


On Sun, Apr 10, 2011 at 12:48:44PM +0200, Bill Allombert wrote:
> On Sun, Apr 10, 2011 at 12:54:57PM +0300, Eugene N wrote:
> > Hello
> > 
> > I am writing some C code, wich will check if a polynomial is irreducible
> > (with libpari *gpolisirreducible*).
> > 
> > Poly will be in the form of int poly[]= {m,m-1,...,0};  (over GF[2])
> > 
> > I am new to pari, and so far i only have seen *gp_read_str *as means of
> > initializing a GEN object from C string.
> > 
> > But in general, how can i initialize a poly from array?
> 
> Read section 4.5.10 of the manual:
> 
> The following sample function convert poly to a GEN of type t_POL with 
> integers coefficients. You can then use FpX_nbfact(x,gen_2)==1 to check for 

I forgot that FpX_nbfact assumes x to be squarefree and it probably better to use
FpX_is_irred(x,gen_2) instead.

Cheers,
Bill.