Choosing multiplication algorithm

[Torbjorn Granlund]

I updated http://gmplib.org/devel/ with some curious diagrams for
multiplication algorithm selection.

We currently (in the development sources) have 9 Karatsuba/Toom
variants, then also schoolbook multiplication and large-ring Schönhage
FFT multiplication, all-in-all 11 algorithms.

But the diagrams have 15 colours, since we also show 4 nested
strategies, used for the most unbalanced operands.

Now we just need to figure out how to best decide which algorithm to use
in GMP.  :-)

(Thanks goes to Marco Bodrato for the idea to compare like this.)

-- 
Torbjörn