Re: KISS 64-bit pseudo-random number generator

In article <2024Sep9.105514@mips.complang.tuwien.ac.at>,
Anton Ertl <anton@mips.complang.tuwien.ac.at> wrote:

mhx@iae.nl (mhx) writes:

On Mon, 9 Sep 2024 6:55:49 +0000, Lars Brinkhoff wrote:
>
[..]

I would like to recommend Marsaglia's newer and better xorshift family
of PRNGs, and preferably the further development by Sebastiano Vigna
called xoroshiro.  The output (with suitable parameters) is very good*,
yet the implementation is very simple.
>
*But not cryptography grade.

>
Being "cryptography grade" is the point when you want to introduce
something new for a PRNG :--)

>
Having better randomness at the same speed or better speed with
similar randomness is also relevant outside cryptographic
applications.
>

1320>> : RANDOM        seed  $107465 *  $234567 +  ( -- u )
1321:                  9 ROL DUP TO seed ;

>
So this is a linear congruential generator enhanded with the 9 ROL.
LCGs have known weaknesses that are relevant even for
non-cryptographic applications.  Maybe the ROL fixes those; have you
run it through ransomness testers?

A naive use of those RANDOM generators without the crutch:
RANDOM 6 MOD 1+
(Simulating a roll of the dice)

Then you discover that rolls of the dice, uneven and odd
number of eyes alternate ..

There is much to be said to use a high quality random
generator to begin with. The expertise to identify faults
with random generators is high.

Those types also have a high correlation between subsequent
points, making it unfit to select a random point in a
two dimensional plane.

I know Marcel uses the random generator for games, which is
okay.

- anton

Groetjes Albert
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