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## Re: [bug-gawk] New multiplication algorighm

**From**: |
Peter Brooks |

**Subject**: |
Re: [bug-gawk] New multiplication algorighm |

**Date**: |
Sat, 20 Apr 2019 06:56:26 +0200 |

Thank you - that's most helpful. I'm pleased that I asked. I certainly
don't find myself working with numbers with over a thousand digits!
On Fri, 19 Apr 2019 at 22:58, Nelson H. F. Beebe <address@hidden>
wrote:
>* 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.*
>
>
>
>* -------------------------------------------------------------------------------*
>* - Nelson H. F. Beebe Tel: +1 801 581 5254*
>* -*
>* - University of Utah FAX: +1 801 581 4148*
>* -*
>* - Department of Mathematics, 110 LCB Internet e-mail:*
>* address@hidden -*
>* - 155 S 1400 E RM 233 address@hidden*
>* address@hidden -*
>* - Salt Lake City, UT 84112-0090, USA URL:*
>* http://www.math.utah.edu/~beebe/ -*
>
>* -------------------------------------------------------------------------------*
>
>
--
Peter Brooks
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