Re: [bug-gawk] New multiplication algorighm

[Nelson H. F. Beebe]

The new O(n log n) multiplication algorithm has a large constant of
proportionality, so it may not matter in practice.  In any event, I
posted a note about it to the gmp developers lists a week ago: see the
thread archived at

        https://gmplib.org/list-archives/gmp-devel/2019-April/thread.html

The mpfr library sits on top of gmp, and so is unlikely to be
interested in the low-level multiplication algorithm.  Multiple
precision libraries are often tuned to use different algorithms for
multiply, divide, and square root, depending on the number of digits
needed: the Fast Fourier Transform algorithm for multiplication is one
such, but experiments in various multiple precision packages show that
one may need to be working with a thousand or more digits before it is
faster than the conventional schoolbook algorithm that takes O(n**2)
time.


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