Re: Normalization of rational functions

On 2023-12-05 15:03, Ruud H.G. van Tol wrote:
> On 2023-12-04 04:39, Ilya Zakharevich wrote:
>> I thought this has been fixed some time ago:
>>
>>     (19:36) gp > t; (-t0*t^2 + 2*t - t0)/(-t^2 - 1)
>>     %1 = (-t0*t^2 + 2*t - t0)/(-t^2 - 1)
>>
>> Should not the normalization choose the positive sign for the
>> leading(?)  coefficient of the denominator?  (Or at least the
>> numerator?)
>
> On my 2.15.4 gp-terminal:
>
> ? (-t0*t^2 + 2*t - t0)/(-t^2 - 1)
> %1 = t0 + 2*t/(-t^2 - 1)
>
> ? t=x
> %2 = x
>
> ? (-t0*t^2 + 2*t - t0)/(-t^2 - 1)
> %3 = (-t0*x^2 + 2*x - t0)/(-x^2 - 1)

So to get your exact output:

? t=t
%1 = t

? (-t0*t^2+2*t-t0)/(-t^2-1)
%2 = (-t0*t^2 + 2*t - t0)/(-t^2 - 1)

? type(t)
%3 = "t_POL"

-- Ruud