Re: How do I ...

[Bill Allombert <Bill.Allombert@math.u-bordeaux1.fr>]

On Wed, Jul 01, 2009 at 04:34:24PM -0400, Bill Daly wrote:
> I can't seem to find a function that does this in PARI, but I suspect  
> there is one, that I've forgotten about.
>
> I have a vector of Polmods, and another Polmod which I know to be a  
> rational linear function of the components of the vector. How can I get  
> PARI to calculate this for me?

I suppose you can use plain old linear algebra: reduce the problem
to solve AX=B where A is the matrix of the Polmod and B is the vector
of the resulting POLMOD.

If your POLMOD are in the same number field K, you can use nfalgtobasis
to express them in the integral basis, which make it a bit easier to write the
matrix.

(I do not think PARI has a dedicated function for this task nor for the other,
but it can be done by linear algebra).

Cheers,
Bill.