online shuffle
I had wondered before if online sites randomly shuffled a deck before the hand, and then used that shuffle throughout the hand. The alternative, obviously, would be to shuffle each time a card or cards are required.
I just read Perry Friedman's response to the question and FTP really does randomly generate cards each time they are needed. Without permission, I quote:
Actually, the way things are done, it actually is less taxing on the
"entropy pool" since cards are only requested as needed. Hence, the
entire deck need not be set before a hand is dealt. If there are only
5 people preflop, only 10 cards are requested initially. If there is
no flop, no further cards are requested.
The actual process is that basically there are banks of decks.
There is a 52 card deck, a 51 card deck, etc. More correctly,
there are banks of unique indices, 0..51, 0..50, etc.
As some examples, when the down cards are ready to be dealt to a full table,
the table would ask for 18 cards from a 52 card deck.
18 random cards are selected using a Knuth algorithm from a 52 card deck.
The actual random numbers are selected from a hardware TRNG (not a PRNG)
meaning it is TRULY random on a quantum physics level. This source
is XOR'ed against an PRNG as a failsafe against hardware malfunction.
The process of obtaining the 18 cards from the 52 card deck caused
the deck itself to be reordered.
Hence, the next request for cards from the 52 card deck would start
with a different initial state than the previous request.
The request for cards returns 18 unique indices between 0 and 51.
Now, when it comes time to deal the flop, the table asks for 3 cards
from a 34 card deck. The table knows what cards are left in it's own
deck. All the RNG returns is 3 indices between 0 and 33, which are
used to pick from the remaining cards in the table's deck.
Again, the process of choosing these new indices causes the 34 card deck
(or more correct, the set of indices from 0 to 33) to be reordered.
This means that all tables are basically shuffling decks for each other,
and that the timing of the hand affects the outcome (in two ways... first,
the TRNG itself will return different results depending on when it
is queried, because it is not a PRNG and is stateless... it's is truly
random... second, even if the TRNG returned the same numbers, other tables
could have modified the state of the indices before you made your
request).
And yes, this effectively makes rabbit hunting useless. I actually like
this. It removes any guilt about folding a hand. You can't say
"I would have won had I called preflop" because the board would have
been different.
Perry |
