Cancellation with hgcd / unbalanced mulmod_bnm1
tg at gmplib.org
Sat Nov 12 19:46:17 CET 2011
nisse at lysator.liu.se (Niels Möller) writes:
Torbjorn Granlund <tg at gmplib.org> writes:
> I think you forgot the save-the-transform trick.
> Since b is implicitly invariant over several a_i pieces,
> evaluating b once will be a slight win.
That's a bit difficult to do with current interfaces, though. And I
suspect that for this non-extreme unbalancedness, toom42/62/63 is a
With toom62 we need quite large operands due to costs for the
Perhaps one should look into a specialised toom-like primitive that
directly takes the cancellation into account? This should not be hard
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