Blackjack Simulator

I've always been fascinated by Blackjack. Some pros say that, if you follow a basic strategy, your odds of winning go up significantly. So, that got me wondering:

If you follow a Blackjack strategy algorithmically, how will you do?

This tiny app is meant to address that.

Disclaimers

I actually don't know very much at all about Blackjack.
There might be bugs, so the numbers may be incorrect.
Memorizing strategy (probably) doesn't make up for knowing the game.

How does it work?

You author a strategy with a pretty straight forward DSL. The app will run this strategy against a given number of games (default 100) and output how it does.

Strategy DSL

Here's an example strategy.

[soft]
   2 3 4 5 6 7 8 9 10 A
13 H H H H H H H H  H H
14 H H H H H H H H  H H
15 H H H H H H H H  H H
16 H H H H H H H H  H H
17 S S S S S S S S  S S
18 S S S S S S S S  S S
19 S S S S S S S S  S S
20 S S S S S S S S  S S
21 S S S S S S S S  S S

[hard]
   2 3 4 5 6 7 8 9 10 A
 4 H H H H H H H H  H H
 5 H H H H H H H H  H H
 6 H H H H H H H H  H H
 7 H H H H H H H H  H H
 8 H H H H H H H H  H H
 9 H H H H H H H H  H H
10 H H H H H H H H  H H
11 H H H H H H H H  H H
12 H H H H H H H H  H H
13 H H H H H H H H  H H
14 H H H H H H H H  H H
15 H H H H H H H H  H H
16 H H H H H H H H  H H
17 S S S S S S S S  S S
18 S S S S S S S S  S S
19 S S S S S S S S  S S
20 S S S S S S S S  S S
21 S S S S S S S S  S S

The [soft] section describes soft-hand strategy. The [hard] section describes hard-hand strategy.

The actions are described as follows.

H = hit
D = double
S = stand

You can run that strategy through the simulator like this.

$ ./go-blackjack --strategy=strategies/passive --games=10000
2013/11/09 22:31:07 Loading strategy strategies/passive
2013/11/09 22:31:09 Total Hands         551588
2013/11/09 22:31:09 Total Wins          213924  (38.783%)
2013/11/09 22:31:09 Total Losses        277828  (50.369%)
2013/11/09 22:31:09 Total Pushes        49836   (9.035%)

Does it actually work??

I dunno. So far, I've tried two different strategies and here are my results for each.

Passive Strategy

This strategy is checked in to the repo.

$ ./go-blackjack --strategy=strategies/passive --games=100000
2013/11/09 22:32:12 Loading strategy strategies/passive
2013/11/09 22:32:33 Total Hands         5515165
2013/11/09 22:32:33 Total Wins          2141896 (38.836%)
2013/11/09 22:32:33 Total Losses        2780783 (50.421%)
2013/11/09 22:32:33 Total Pushes        492486  (8.930%)

Wizard of Odds Strategy

This strategy is also checked in to the repo and described on the Wizard of Odds website.

NOTE: One big missing piece that is described in the Wizard of Odds strategy that is missing here is splitting. This simulator does not support it!

$ ./go-blackjack -strategy strategies/wizard_simple -games 100000
2013/11/09 22:25:13 Loading strategy strategies/wizard_simple
2013/11/09 22:25:33 Total Hands       5562401
2013/11/09 22:25:33 Total Wins        2275528 (40.909%)
2013/11/09 22:25:33 Total Losses      2761467 (49.645%)
2013/11/09 22:25:33 Total Pushes      425406  (7.648%)

Assumptions

/dev/urandom is sufficiently random for our purposes.
Not shuffling between hands is OK.
Simulates a six-deck shoe by default.

Contributing

You know what do! Fork and submit a pull request. Strategies are, of course, welcome as well.

ronniebnorth/go-blackjack