Simulate Games

simulateGame.ts

// For each player simulate the player answering series of questions and observe rating changes
export default function simulateGames(
    ratingSystem: RatingSystem,
    players: Player[],
    questions: Question[],
    numQuestionsPerPlayer: number,
    ratingRange: number
): Result[] {
    const results: Result[] = []

    for (const player of players) {
        for (let i = 0; i < numQuestionsPerPlayer; i++) {
            // Get opponentn for player using current ratings
            // Would simulate another matching system which pairs condidate players
            const minRating = player.rating - ratingRange
            const maxRating = player.rating + ratingRange
            const isRatingWithinRange = (question: Question) => minRating <= question.rating && question.rating <= maxRating
            const question = getRandomWhichMeetsConstraints(questions, isRatingWithinRange)

            // Need to expose the probabilities in order to compute the outcome
            // For the simulation we want the score biased based on the skill difference
            // Intention is the better / more knowledgeable user is more likely to score / answer correct
            const [playerProbability, questionProbability] = ratingSystem.getPlayerProbabilities(player.rating, question.rating)
            const expectedOutcome = playerProbability > 0.5 ? 1 : 0
            const playerOutcome = Math.random() < playerProbability ? 1 : 0
            // const questionOutcome = 1 - playerOutcome

            const nextRatingsInfo = ratingSystem.getNextRatings(player.rating, question.rating, playerOutcome)

            const result: Result = {
                iteration: i,
                playerId: player.id,
                questionId: question.id,
                playerRating: player.rating,
                questionRating: question.rating,
                playerProbability: playerProbability,
                questionProbability: questionProbability,
                playerOutcome,
                expectedOutcome,
                updatedPlayerRating: nextRatingsInfo.nextPlayerARating,
                updatedPlayerDiff: nextRatingsInfo.playerARatingDiff,
                updatedQuestionRating: nextRatingsInfo.nextPlayerBRating,
                updatedQuestionDiff: nextRatingsInfo.playerBRatingDiff
            }

            player.rating = Math.round(nextRatingsInfo.nextPlayerARating)
            question.rating = Math.round(nextRatingsInfo.nextPlayerBRating)

            // console.log(`add result: ${player.id} i:${i}`)
            results.push(result)
        }
    }

    return results
}