blackjack-simulator

Features

• Efficient: Concurrency enabled by default, able to simulate millions of games in seconds.
• Customizable: Easily change the number of decks, rules, and more.
• Reproducible: Exact same result can be achieved by using the same seed and version.
• Simple: No dependencies, released as just a single binary to run.

Installation

Native Binary

You can download the latest release from the Releases page.

Docker Image

Alternatively, you can run the simulator using Docker (assuming you have a config.json file in the current directory):

docker run --rm -it -v ./config.json:/app/config.json jljl1337/blackjack-simulator

Usage

Flags

Flag	Description
-config	Path to the configuration file (default: config.json), see Configuration for details.
-csv	Path to the CSV file to write results to if specified.
-num-workers	Number of concurrent shuffles to run (default: number of CPU cores).
-verbose	Enable verbose output.

Configuration

Sample configuration file can be found in the repository root as config.json.

Field	Type	Description
seed	int64	Random seed for reproducible results. If not provided or set to 0, uses current timestamp.
numShuffles	uint	Number of shuffles to simulate.
numRounds	uint	Number of rounds to simulate.
numHands	uint	Number of hands to simulate.
numDecks	uint	Number of decks in the shoe. Must be greater than 0.
penetration	float64	Shoe penetration percentage with a range of (0, 1]. Determines portion of the shoe that is dealt before reshuffling.
doubleAfterSplit	bool	Whether doubling down is allowed after splitting a pair. Default: false.
hitAfterSplitAce	bool	Whether hitting is allowed on hands formed by splitting aces. Default: false.
splitAfterSplitAce	bool	Whether re-splitting aces is allowed. Default: false.
doubleAfterSplitAce	bool	Whether doubling down is allowed on hands formed by splitting aces. Default: false.
maxNumHands	uint	Maximum number of hands a player can have after splitting. If not specified, defaults to 4. If explicitly set to 0, splitting is disabled. If set to -1, splitting is allowed without limit.
surrenderAllowed	bool	Whether surrendering is allowed. If not specified, defaults to true.

Important

The numShuffles, numRounds, and numHands fields are mutually exclusive, exactly one must be specified with a value greater than 0.