PHP mt_srand no longer seeds same number!!!!! aaarrrg

[A]

Hi all.

Is this a bug or what???

here is a simple code:

<?php
mt_srand(1);
echo mt_rand(0, 255)."<br />";
echo mt_rand(0, 255)."<br />";
echo mt_rand(0, 255)."<br />";
echo mt_rand(0, 255)."<br />";
?>

It should produce the SAME sequence every time when run.

however... it does not on PHP 5.2.6 on the linux box.

But on my test environment (windows) - php 5.2.3 does work properly!

So what am I missing? How do I get the same random sequences based on
mt_rand and mt_srand? I need same sequences based on starting seed!

I looked at the docs and it says:

The Mersenne Twister implementation in PHP now uses a new seeding
algorithm by Richard Wagner.
Identical seeds no longer produce the same sequence of values they did
in previous versions.
This behavior is not expected to change again, but it is considered
unsafe to rely upon it nonetheless.
but it says - AFTER 5.2.1 --- and I have both versions ABOVE 5.2.1...what to
do? ideas? pleeeeeeaseeeee eee! :)

[Twayne]

.oO(Twayne)

>

>>On Sep 12, 4:39 am, Jerry Stuckle <jstuck...@attg lobal.netwrote:

And a "repeatable sequence of random numbers" is an oxymoron. Yes,
many people have used a random number generator as a quick way to
generate a repeatable sequence. I consider THAT a bug.

That's only because people are using the terminology colloquially.
What they mean is a "repeatable sequence of numbers which are
statistical ly random." It's entirely expected behavior that when
using the same seed one will get that. Especially if that's the
behavior of previous versions of the system.

umm, no, not unless that was the design goal, which I don't think it
was or it wouldn't have been "fixed".

If it would have been a design mistake, then there wouldn't be a seed
function. But it exists, hence the previous behaviour was by
intention.

>Random is random is ... . A
randomizer that regenerates the same numbers is not creating truly
random numbers, is it?

Truly random numbers require some more effort and can't be created
with software alone.

A software-based generator only creates pseudo-random numbers, based
on algorithms. Such algorithms are usually deterministic - same
input, same output.

No arguement there. It's just that if I want "random" numbers I don't
want to see a number repeat itself more than once in great while
coincidence type manner. When I want a set of random numbers back, I
want to pull them from storage somewhere, not repeat the random number
generation to get them; that makes the name oxymoronic IMO; thus, a
misnomer of sorts.
I know, it's been discussed for eons so I won't work to draw this out
into long diatribes; it's kind of OT anyway at this point I think.
I remember my first experiences with random numbers back in the days
of CP/M basic and at first I thought it was pretty neat stuff until I
realized all it did was read a system timer and then manipulate it
accordingly<g>.
Now if I could just get my ISP to move up to something more current
than PHP 5.2.2 I'd really be all set.

Regards,

Twayne

>
Micha