Codelets for ToomN1 (for N=2, 3, 4, 6, 8) should be added and here's why. (Also: a significant non-triviality on where cut-off points should be).

[paul zimmermann]

       Dear Marco,

> By the way, in the last message I forgot to point to some graphs we
> elaborated to show where each multiplication variant is better. They can
> be found at https://gmplib.org/devel/, under the title "New Toom
> multiplication code for unbalanced operands".
> Those graphs are old, they did not yet take into account either Toom6h or
> Toom8h.

indeed, those graphs clearly show that a simple threshold mechanism is not
optimal. I'd like to see a similar graph for 0 < n < 256.

> Should we really stop the bi-dimensional table at Toom8h? What about the
> dispersed border Toom-versus-FFT?
> 
> Maybe a more fine-grained table for small sizes... then another table for
> larger values.. We shall thinkabout that.

yes maybe you need a table with floating-point entries :-)

Paul