Poker Solver

Motivation

This tool will help you approximate your winning chance in a Texas Holdem poker game. There is a web front end for this tool at here

Without a doubt, luck plays a significant role here, but stepping into the game without a good mathematical foundation is equivalent to doing charity. I hope my codes can do a little help preparing you on that aspect ☺

Install

Build main program

Install rustup if you have not done so. Then build the program with

cargo build

Build for the web

You need wasm-pack

wasm-pack build --target web

Output would be at pkg folder, install it using npm install ./path/to/pkg/

Run

Run the program with

cargo run -- <Community Cards> <Your Hand> [Their Hand]
# Example
cargo run -- 2s3s4d6s7s AsAd KsQs
cargo run -- 2s3s4d AsAd
cargo run -- 2s3s4d3d AsAd
# or you can run it directly like this
./poker-solver 2s3s4d3d AsAd

Input format

Community cards consist of 3-5 cards
Your hand consist of 2 cards
Their hand consist of 0-2 cards

Card notation

A card represented by 2 characters, card rank and card suit
Card rank can accept 23456789TJQKA
Card suit can accept scdh, stand for Spade ♠, Club ♣, Diamond ♦, Heart ♥

The program will output all possible game outcomes. Here is an example:

🎴 Community cards:       2♠3♠7♠
🎴 Your hand:               A♠A♦
🎴 Their hand:

👑 Win:                   976740
💸 Lose:                   92820
🤝 Tie:                      630
🧮 You win:            91.26791%

Methodology

Hand evaluation

I use some bit math to match given hand of cards to a set of precomputed patterns. Then rank the hand accordingly. Kindly check src/poker/evaluator.rs for single game evaluation algorithm. Kindly check src/poker/game.rs for outcome simulation algorithm.

Performance

Here are the number of possible outcome in each given game phase

	Flop (2 hidden cards)	Turn (1 hidden card)	River (All cards visible)
Possible Outcomes	1070190	45540	990

Here are some tests I made, you can run those tests yourself with

cargo test

Test Case	Game Code	Solve Time	Possibility
Both hands revealed, Flop	AsAd,KsKd,2s3s7s	84.6ms ± 2.2ms	990
All community cards revealed	AsAd,,2s3s4s5s6s	50.2ms ± 2.7ms	990
Turn	AsAd,,2s3s4s5s	290.0ms ± 2.9ms	45540
Early royal straight-flush	KsAs,,TsJsQs	3.721s ± 0.069s	1070190
Early quad	AsAc,,AdAhKs	4.334s ± 0.082s	1070190
Early full-house	AsAd,,2c2s2d	2.787s ± 0.033s	1070190
Early pair of Ace, +1 card to flush/straight	AsAd,,2s3s4s	3.999s ± 0.029s	1070190
Early pair of Ace	AsAd,,2c6s8s	4.412s ± 0.012s	1070190
High cards	TdQh,,2c6s8s	4.415s ± 0.031s	1070190
Low cards	6s2h,,8cTdQh	4.282s ± 0.019s	1070190

The program perform relatively well given the large number of possibilites
With wasm version, expect 2~4 times slower (which is ~16 seconds worse case, still acceptable by my standard)

hucancode/poker-solver