go-chess-minimax, v1.1

The library that implements a chess engine based on the minimax algorithm.

Implement the alpha-beta pruning and a tournament between different versions of the move searcher.

Change Log

• optimize move searching via the alpha-beta pruning;
• implement a tournament between the negamax algorithm and it with the alpha-beta pruning.

Features

• move searcher used the negamax algorithm;
• optimizations:
  • alpha-beta pruning;
• searching termination:
  • by a deep;
  • by a time;
• position evaluation only by a material (based on an evaluation function of Claude Shannon);
• architecture features:
  • easily extensible and composable architecture of searching;
  • composable searching terminators.

Examples

chessminimax.AlphaBetaSearcher.SearchMove():

package main

import (
    "fmt"
    "log"

    minimax "github.com/thewizardplusplus/go-chess-minimax"
    "github.com/thewizardplusplus/go-chess-minimax/evaluators"
    "github.com/thewizardplusplus/go-chess-minimax/terminators"
    models "github.com/thewizardplusplus/go-chess-models"
    "github.com/thewizardplusplus/go-chess-models/pieces"
)

func main() {
    storage, err := models.ParseBoard("7K/8/7q/8/8/8/8/k7", pieces.NewPiece)
    if err != nil {
        log.Fatal(err)
    }

    var generator models.MoveGenerator
    var evaluator evaluators.MaterialEvaluator
    terminator := terminators.NewDeepTerminator(1)
    searcher := minimax.NewAlphaBetaSearcher(generator, terminator, evaluator)

    scoredMove, err :=
        searcher.SearchMove(storage, models.White, 0, minimax.NewBounds())
    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("%+v\n", scoredMove)

    // Output: {Move:{Start:{File:7 Rank:7} Finish:{File:6 Rank:7}} Score:-9}
}

Benchmarks

chessminimax.AlphaBetaSearcher:

BenchmarkAlphaBetaSearcher_1Ply-8           1000       2059163 ns/op
BenchmarkAlphaBetaSearcher_2Ply-8            300       5603471 ns/op
BenchmarkAlphaBetaSearcher_3Ply-8             50      36132193 ns/op

Repository

Link: https://github.com/thewizardplusplus/go-chess-minimax/tree/v1.1.

Content: code.

License: MIT.

Screenshots

Tournament between negamax and alpha-beta algorithms