(Slots continued)

JavaScript Slot Simulation

     

• See Instructions Below
• See Notes Below

Instructions

You can configure the slot machine and play manually, or you can run a simulation that will play the slot machine automatically. The two features are separate.

To play slot machine

1. Change the default values for the payout, if you like. Click change.
2. Change the default number of symbols per reel, if you like. All three reels will have the same number of symbols. Click change. The number of reels must add up to 21 or the results will be wrong.
3. You can also change the denomination of coin if you like. You do not have to click change on this. And the simulation feature does not use this field.
4. Pull the handle.

To run simulation

1. Change the values for payout and number of symbols per reel like above, if you like.
2. Change the number of trials if you wish. You don't have to click change.
3. Change the starting bankroll if you wish. No need to click change here either.
4. Click the "run sim" button.
5. To interrupt a simulation, click "stop".
6. Before running again, click "reset".

Notes

The purpose of this script is to help people understand the general nature of slot machines. I have often heard people agree that you could not win at slots and then go on to explain their theories on how to win at slots. This JavaScript slot simulation was made with them in mind. Please read the instructions before using it.

Entering non-numeric or otherwise strange input into the text fields will produce bad results. I make no effort to check the input.

The maximum number of slots on each reel is 21.

In real slot machines, the number of symbols per reel will vary. In other words, you may have two cherries on one reel, three on the middle reel, and five on the last. On this slot slim, if you have 2 cherry symbols on one reel, you have two each on the other two also.

Probability when the payout is based on three symbols: (number per reel^3)/(21^3)

Probability when the payout is 2/3 symbols: (number per reel * number per reel * (21-number per reel) * 3)/(21^3)

Contribution is: probability * payout * (21^3)

Return is: contribution/(21^3)

Total return can be sum of all returns, or sum of all contributions/(21^3). If you some all the returns and compare with the display, there may be a slight difference due to rounding.

The sim return rate is just the actual rate of return for the simulation. I put this here for comparison purposes.

The number of times to expect each winning combination is not shown, however you can multiply the probability by 21^3(9261) or divide contribution by the payout to get the figure.

Clicking on fields and interacting with the interface while a simulation is running or while the slot is spinning will have undetermined results. (With the exception of the stop button.)

The "Sim Return" field is rather worthless and misleading, and I'm going to change this the next time I take a notion to do so. I was thinking it could be used to compare with the return rate, as a check to see how close the simulation got. However, this is faulty. If you do 21^3 trials the majority of time it should be somewhere around the calculated return rate. But what happens is the edge chips away at the bankroll after a certain number of trials, and then the "Sim Return" drops drastically? If enough trials are used, the player will be wiped out and the "Sim Return" would be 0, which of course does not make sense.