Re: [math] integer factorization

["matic@nimp.co.uk" <ma...@nimp.co.uk>]

Hello,

Thanks for your feedback and the pointer to PARI/GP. About existing stuff,
it seems there is none written in Java: I asked the question on
stackoverflow a while ago, nobody knows any library for the JVM.
About the applications, well, I agree it is not the #1 required
functionality in most applications. Still applications beyond pure maths do
exist: hash tables, pseudo random numbers, cryptography, electronics...
Clearly the int range is not enough for the standard public key
cryptography however it is enough for most of other applications (and
standard crypto stuff is fairly covered out of the box by java anyway).

I propose this because I looked for it, and ended up spending significant
time coding and testing it, so I though it would be useful to include it in
a library such as commons.math.

Best regards,
Sebastien

Original Message:
-----------------
From: J.Pietschmann j3322ptm@yahoo.de
Date: Tue, 31 Jul 2012 21:35:12 +0200
To: dev@commons.apache.org
Subject: Re: [math] integer factorization


Am 25.07.2012 08:26, schrieb matic@nimp.co.uk:
> It seems there is no open source library providing support for integer
> factorization, what about implementing it in commons.math ?

There are quite a few open source libraries providing integer
factorization, e.g. pari/gp (http://pari.math.u-bordeaux.fr/).

The question is, why do you think such a functionality would be useful
for commons math? There aren't all that much practical use cases for
factorization, in particular if it is limited to the Java integer range,
unless you want to implement a computer algebra system or you have to
deal with certain specific problems in discrete mathematics (neither of
which is in the focus of commons math).

J. Pietschmann

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Re: [math] integer factorization

["J.Pietschmann" <j3...@yahoo.de>]

Am 04.08.2012 14:22, schrieb matic@nimp.co.uk:
> Thanks for your feedback and the pointer to PARI/GP. About existing stuff,
> it seems there is none written in Java: I asked the question on
> stackoverflow a while ago, nobody knows any library for the JVM.

Hehe, even StackOverflow fails occasionally. Try
 http://krum.rz.uni-mannheim.de/jas/
for a start. Search for "java quadratic sieve" for some more code,
although most of the results seems to be more sample code rather than
production quality.
I vaguely remember there should be up to 12 Java based projects
including more or less sophisticated integer factorization stuff,
although I'm not current there and most of them could be dead.

> About the applications, well, I agree it is not the #1 required
> functionality in most applications. Still applications beyond pure maths do
> exist: hash tables, pseudo random numbers, cryptography, electronics...

Yes, developing and testing hash algorithms, pseudo random number
generators, crypto stuff etc. uses factorization, but everyday use
generally doesn't.
Apparently you are into serious hard core stuff. As fascinating as these
problems most likely are, they are not the primary target for commons
math, at least until now.


J.Pietschmann

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