[fpc-devel] Arbitrary-precision arithmetic unit

Alexander Klenin klenin at gmail.com
Mon Mar 2 13:28:49 CET 2009

On Mon, Mar 2, 2009 at 21:58, Michael Schnell <mschnell at lumino.de> wrote:
> In the "Deutsches Lazarus Forum" there was a project called "GNURZ"
> providing this. It was quite promising and I provided some ASM-optimization
> for it.
> Here the original Author implemented a "Karazuba" multiplication, that is a
> lot faster than the standard Multiplication algorithm, when very long
> numbers are handled (see Wikipedia on Karazuba).

It is Karatsuba, actually (he is Russian professor). I studied this
algorithm at university.
I vaguely remember that although it is asymptotically faster than FFT,
is complicated and the time constant is higher, so FFT is used in
practice except
for really large problems.

> Unfortunately the original Author has stopped to work on the project and
> nobody seems to be inclined to do some necessary cleaning up of the code to
> allow a community based development.

Unfortunately, I do not read German, so I it is hard for me to understand,
and this code even uses German procedure names (!).
If someone will at least provide an english translation, I might help
with code cleanup
to get the code ready for FPC inclusion.

For now, NX library with LGPL license fulfills my needs.

> The license seems to be no problem at all.

Good, although getting explicit license from the author is always preferable.

Alexander S. Klenin

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