Are the dice rolls random? |

Many players have certain doubts about the fairness of Ariston BackGammon. Some people suggest the program actively cheats by manipulating the rolls it needs at critical times. Others just wonder if the program's roll generator is defective causing it to produce more good rolls for itself than for its opponents. HOW DICE ARE GENERATED ON A COMPUTER.To get random dice, Ariston is using a random dice generator. This is a pc-internal program that delivers "pseudo-random-numbers" It is a mathematical routine which produces a series of numbers that behave just like the numbers you would get by rolling precision dice for a long time. Over a long sequence, all numbers appear with equal frequency, and it is not possible to predict a future number! Protocol of the random dice generatorTHE ROLLS ARE GENERATED AS FOLLOWS:When a new game starts, Ariston using the internal pc-timer to get the time in milliseconds. The time is multiplied by hundred and delivers a number between 0 and 8640000 which is known as the "Seed". This number is very important to understand how a random dice generator works! You can see the last-generated number (Seed) down on the status bar. Once the seed is established, a mathematical function is applied which generates pairs of numbers between 1 and 6, which are the dice rolls for the current game. When a new game is started, a new seed is generated and the process begins again. VERIFYING THE SEQUENCE OF DICEOne way to verify that Ariston BackGammon is not generating dice to its own advantage is to use the function "Enter Seed" in the menu. It will reset the random dice generator and you will get the sequence of dice rolls connected with this seed. - Clear the board.
- Enter any seed you like and record this number.
- Toss the dice and record the sequence of dice rolles as long as you like.
- Start a game and make a few moves.
- Now enter your seed again and continue the game
In other words, the dice sequence is not dependent on the board position, but only on the seed used to start the game. You may enter any seed you like at any time and you will always get the same sequence of dice rolls connected with this seed ! I.e. Enter the seed 123 and you are going to get the following dice rolls: 6+1 - 1+1 - 6+1 - 4+3 - 3+2 - 6+5 - 6+2 - 2+1 - 3+2 - 6+4....... METHOD FOR VERIFYING THAT "Ariston Backgammon" DOES NOT TAKE ADVANTAGE OF UPCOMING ROLLSSince the sequence of rolls in the game is determined by the initial seed, you might believe that Ariston BackGammon adjusts its plays to take advantage of upcoming rolls. Here's how to verify that this is not happening.Play a game against Ariston BackGammon as usual. If you think Ariston Backgammon was cheating because it was knowing the upcoming roll, set up these position (with the suspicious move) in the edit modus. When you are finished click the -key to let Ariston make its move. (The move that you believe it is fabricated for the next roll.) Now store the postion in the archive and you can load this position as much as you like from the archive and let the game make its (suspicious/fabricated) move. Note: Although the next roll will now be different, the program is going to make the same move over and over ! Click on the dice to affirm that the next roll is indeed different. However, in case the roll is not dissimilar, please repeat with loading the position again and roll again. In some rare cases the program has found more than one good move and it will select at random one of these moves. In this case you will see one of these moves but also the suspicious one... Notice that Ariston BackGammon always executes the best move as a function of its evaluation facility only and not as a fabricated play so as to take advantage of upcoming rolls. |

In my experience, many people who complain about Ariston's "luck" have never had the experience of playing a truly strong opponent. Those who play well appear lucky because they create positions where more of their own rolls play well, while more of their opponent's rolls play badly. The effect of this is that the strong player appears to roll better.If you still think you' ve been the victim of bad dice, feel free to use real dice for a while and enter the rolled numbers into the Ariston-dicebox.Please have a look too at:
www.ariston-backgammon.de/ariston_backgammon_lesson_1.html
Michael Rosner |