On August 24, 2023 at 6:18:41 AM UTC-6, Timothy Chow wrote:
> On 8/23/2023 6:08 PM, MK wrote:
> > I don't believe you :) Can you demonstrate this
> > using Noo-BG, for example, which has a 32-bit
> > Mersenne Twister and allows setting the seed?
> I doubt that you'd be convinced by anything
> short of working code,
I wasn't thinking anything of no such things
at all. I'll be satisfied if I give you 8 rolls and
you tell me what was the seed I used.
> I'm not going to produce working code, because
> someone might actually use it to cheat.
This sounds eerily deja vu. I can't be sure who
had said it but his reason for refusing a similar
request was exactly the same. In this case, I'm
not even asking for it.
> If you're too lazy to learn the math,
To the contrary, I'm asking you because I want
to learn the maths but I wouldn't want to learn
the wrong math/s.
> or prefer to sting like a scorpion because
> that's your nature, then that's your problem.
Whoa! Slow down, turtle! No need to call out to
scorpions (not yet anyway ;)
>>> The Mersenne Twister algorithm becomes
>>> predictable after a while, but this loophole
>>> can again be plugged if we simply agree to
>>> refresh the seed after a certain period of time.
>>> We'd have to check the details of the generator
>>> to be certain, but the number of dice rolls in a
>>> 31-point match is probably small enough that
>>> refreshing the seed after each match is good
>>> enough.
>>> Wikipedia says that 624 observations of
>>> MY19937 is enough to recover the seed, but I
>>> think this assumes that you see the full 32-bit
>>> word each time, so it probably translates into
>>> more than 624 dice rolls.
> Here I was assuming that the full 19937 bits of
> the seed were being used, not just 32 bits of it.
I wasn't making an issue out of 19937 vs 32 bits.
>> About your last sentence above, I think Ex-Gee
>> and Noo-BGt derive dice numbers simply from
>> modulo 6 of those 624 numbers in the array.
>> So, one would need to know all 624, (i.e. at least
>> 312 dice pairs), in order to know the following
>> roll in line.
> Again, this would only be if the full seed were
> being used.
If you are going to respond to me without reading
what I write, what's the point of discussing..? I'm
not going to repead what I had written after what
you quoted from my post. You can go back and
read it again. But I'll add a few lines quoting from
myself in the link I had given, (which apparently
you didn't bother to read either):
"Lo and behold! Your total moves for a 5-point
"cubeless gamblegammon match is 324, for a
"13-point cubeful gamblegammon match is 351.
"Similarly, for a 7-point cubeless gamblegammon
"match is 465, for a 19-point gamblegammon
"match is 530.
Thus, a 31-point gamblegammon match is likely to
last about 700 some moves/rolls. And even using
the full 19937 bits of the seed, if you can deduce it
only after 624 numbers, i.e. 312 dice rolls, then you
you will start knowing the upcoming numbers only
halfway through a 31-point gamblegammon match.
When I asked: "Can you stand behind either of these
contradicting statements..?", I was asking if you can
stand behind your statement that "refreshing the seed
after each match is good enough in 31-point matches".
If I have to explain what I write like to a 5-year-old kid
too often, I may grow tired of it... :(
> There is no contradiction.
Well, maybe not literally but I was trying to contrast
your claim to deduce a 32-bit seed after only 8 rolls,
(which I believe are too few), against to not deduce a
19937 bit seed even after 312 rolls, (which I believe
are too many).
So, let me ask again trying to be clearer this time:
1- Do you accept that you were overestimating the
dice rolls needed to deduce a 19937 bit seed? (No
additional arguments needed).
2- Do you accept that you were underestimating the
dice rolls needed to deduce a 32 bit seed? (If not, I'd
like you to demonstrate that your math is correct for
me to learn the math correctly).
MK