Improve Monte Carlo CLI output

README.md

@@ -96,6 +96,58 @@ const result = simulateHands(1)
 console.log(result.sessionSummary)
 ```
 
+## monte carlo simulation
+
+Run many trials to see how a strategy performs over time.
+
+```bash
+$ node monte-carlo.js 2 5 500 5 3-4-5
+Running 2 trials with 5 hand(s) each
+[table rules] minimum bet: $5, odds 3-4-5
+
+Trial Results
+┌─────────┬───────┬─────────┬───────┐
+│ (index) │ trial │ balance │ rolls │
+├─────────┼───────┼─────────┼───────┤
+│ 0       │ 1     │ 614     │ 65    │
+│ 1       │ 2     │ 416     │ 25    │
+└─────────┴───────┴─────────┴───────┘
+
+Final Balance Summary
+┌─────────┬────────┐
+│ (index) │ Values │
+├─────────┼────────┤
+│ min     │ 416    │
+│ p1      │ 416    │
+│ p5      │ 416    │
+│ p10     │ 416    │
+│ p25     │ 416    │
+│ p50     │ 416    │
+│ p75     │ 614    │
+│ p90     │ 614    │
+│ p95     │ 614    │
+│ p99     │ 614    │
+│ max     │ 614    │
+└─────────┴────────┘
+
+Roll Count Summary
+┌─────────┬────────┐
+│ (index) │ Values │
+├─────────┼────────┤
+│ min     │ 25     │
+│ p1      │ 25     │
+│ p5      │ 25     │
+│ p10     │ 25     │
+│ p25     │ 25     │
+│ p50     │ 25     │
+│ p75     │ 65     │
+│ p90     │ 65     │
+│ p95     │ 65     │
+│ p99     │ 65     │
+│ max     │ 65     │
+└─────────┴────────┘
+```
+
 ## table rules
 
 `playHand` accepts a `rules` object that controls minimum bets and odds limits.

monte-carlo.js

@@ -0,0 +1,100 @@
+#!/usr/bin/env node
+'use strict'
+
+const { playHand } = require('./index.js')
+const { minPassLineMaxOddsPlaceSixEight } = require('./betting.js')
+
+function parseOdds (str) {
+  const parts = String(str).split('-').map(n => parseInt(n, 10))
+  if (parts.length !== 3 || parts.some(n => isNaN(n))) return {}
+  return {
+    4: parts[0],
+    5: parts[1],
+    6: parts[2],
+    8: parts[2],
+    9: parts[1],
+    10: parts[0]
+  }
+}
+
+function percentile (sorted, p) {
+  if (sorted.length === 0) return 0
+  const idx = Math.ceil((p / 100) * sorted.length) - 1
+  return sorted[Math.min(Math.max(idx, 0), sorted.length - 1)]
+}
+
+function summary (arr) {
+  const sorted = [...arr].sort((a, b) => a - b)
+  return {
+    min: sorted[0],
+    max: sorted[sorted.length - 1],
+    p1: percentile(sorted, 1),
+    p5: percentile(sorted, 5),
+    p10: percentile(sorted, 10),
+    p25: percentile(sorted, 25),
+    p50: percentile(sorted, 50),
+    p75: percentile(sorted, 75),
+    p90: percentile(sorted, 90),
+    p95: percentile(sorted, 95),
+    p99: percentile(sorted, 99)
+  }
+}
+
+function summaryTable (arr) {
+  const obj = summary(arr)
+  const order = ['min', 'p1', 'p5', 'p10', 'p25', 'p50', 'p75', 'p90', 'p95', 'p99', 'max']
+  return order.map(k => ({ stat: k, value: obj[k] }))
+}
+
+function simulateTrial ({ handsPerTrial, startingBankroll, rules }) {
+  let balance = startingBankroll
+  let rolls = 0
+  for (let i = 0; i < handsPerTrial; i++) {
+    const { history, balance: result } = playHand({
+      rules,
+      bettingStrategy: minPassLineMaxOddsPlaceSixEight
+    })
+    balance += result
+    rolls += history.length
+  }
+  return { balance, rolls }
+}
+
+function monteCarlo ({ trials, handsPerTrial, startingBankroll, rules }) {
+  const results = []
+  for (let i = 0; i < trials; i++) {
+    results.push(simulateTrial({ handsPerTrial, startingBankroll, rules }))
+  }
+  return results
+}
+
+function printResults (results) {
+  console.log('\nTrial Results')
+  console.table(results.map((r, i) => ({ trial: i + 1, balance: r.balance, rolls: r.rolls })))
+
+  console.log('\nFinal Balance Summary')
+  console.table(summaryTable(results.map(r => r.balance)))
+
+  console.log('\nRoll Count Summary')
+  console.table(summaryTable(results.map(r => r.rolls)))
+}
+
+if (require.main === module) {
+  const trials = parseInt(process.argv[2], 10)
+  const handsPerTrial = parseInt(process.argv[3], 10)
+  const startingBankroll = parseInt(process.argv[4], 10)
+  const minBet = parseInt(process.argv[5], 10)
+  const oddsInput = process.argv[6] || '3-4-5'
+
+  const rules = {
+    minBet,
+    maxOddsMultiple: parseOdds(oddsInput)
+  }
+
+  console.log(`Running ${trials} trials with ${handsPerTrial} hand(s) each`)
+  console.log(`[table rules] minimum bet: $${minBet}, odds ${oddsInput}`)
+  const results = monteCarlo({ trials, handsPerTrial, startingBankroll, rules })
+  printResults(results)
+} else {
+  module.exports = { monteCarlo, simulateTrial, summary }
+}

package.json

@@ -27,5 +27,9 @@
   "devDependencies": {
     "standard": "^16.0.3",
     "tap": "^15.0.9"
+  },
+  "bin": {
+    "craps-monte": "./monte-carlo.js",
+    "craps-hands": "./hands.js"
   }
 }