OpenEuphoria

Re: Mersenne Twister

• Posted by rforno at tutopia.com Sep 22, 2001
• 383 views

Oh, well, we don't need that for the Mersenne Twister. And of course this
would be sloooowwww...
----- Original Message -----
From: "Kat" <gertie at PELL.NET>
To: "EUforum" <EUforum at topica.com>
Subject: Re: Mersenne Twister


>
> On 21 Sep 2001, at 17:02, rforno at tutopia.com wrote:
>
> >
> > Derek:
> > As per your request, I revised your implementation of the Mersenne
Twister. I
> > found a slight disagreement with the original. The original poses: seed
&
> > 0xffffffff You instead code: remainder(seed, #FFFFFFFF) This does not
give the
> > same result for numbers >= 2^32 - 1, as should be most of the numbers
generated
> > by multiplying the previous one by 69069. Of course Euphoria does not
accept:
> > and_bits(seed, #100000000), but: remainder(seed, #100000000) is Ok and
gives the
> > same result. Maybe the initial matrix is not so important, as stated
elsewhere,
> > and your variant is perhaps better, since the original generates only
odd
> > numbers, and yours generates odd and even numbers nearly at random, but
only to
> > stick to the original...:) A similar problem occurs with the final
result. The
> > maximum value that y + #80000000 can attain is #FFFFFFFFF, and in this
case the
> > result is 1 higher than "range". This is equally solved by substituting
range /
> > #10000000 instead of range / #FFFFFFFF. Even it may be preferable to
write (y +
> > #80000000) / #100000000 * range, to protect against inaccuracies of the
division
> > of range by 2^32. Maybe Rob has something to say about it. Best regards.
>
> What about using string math? You can then build as big a number as you
> wish, in an object used as a sequence?
>
> x = "0283650813749136548740623403784650278362456"--ad infinitum
> return(x)
>
> Kat
>
>
>