Re: What's the code for doing the reverse of this code over the altbn128 curve

This has nothing to do with the order of points, it simply identifies 
elements of F_p(w) that are in fact in F_p(i), and applies this to the 
coordinates of the points.

Aurel

On 18/07/2025 16:12, Laël Cellier wrote:
>
> Thank you, and this would work with any point having the correct 
> order ? or would this work only with points having coordinate withing 
> specific bounds ?
>
>
>
>
>
> Dear Laël,
>
> What you are looking for is ffinvmap:
>
> ? mapi = ffinvmap(map);
> ? twisti(pt) = [ffmap(mapi,pt[1]/w^2), ffmap(mapi,pt[2]/w^3)];
> ? pt3 = twisti(pt2);
> ? pt3 == pt
> %15 = 1
>
> Cheers,
> Aurel