0.2.0 - Mid migration

web/node_modules/worker-farm/examples/pi/calc.js

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+'use strict'
+
+/* A simple π estimation function using a Monte Carlo method
+ * For 0 to `points`, take 2 random numbers < 1, square and add them to
+ * find the area under that point in a 1x1 square. If that area is <= 1
+ * then it's *within* a quarter-circle, otherwise it's outside.
+ * Take the number of points <= 1 and multiply it by 4 and you have an
+ * estimate!
+ * Do this across multiple processes and average the results to
+ * increase accuracy.
+ */
+
+module.exports = function (points, callback) {
+  let inside = 0
+    , i = points
+
+  while (i--)
+    if (Math.pow(Math.random(), 2) + Math.pow(Math.random(), 2) <= 1)
+      inside++
+
+  callback(null, (inside / points) * 4)
+}

web/node_modules/worker-farm/examples/pi/index.js

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+'use strict'
+
+const CHILDREN         = 500
+    , POINTS_PER_CHILD = 1000000
+    , FARM_OPTIONS     = {
+          maxConcurrentWorkers        : require('os').cpus().length
+        , maxCallsPerWorker           : Infinity
+        , maxConcurrentCallsPerWorker : 1
+      }
+
+let workerFarm = require('../../')
+  , calcDirect = require('./calc')
+  , calcWorker = workerFarm(FARM_OPTIONS, require.resolve('./calc'))
+
+  , ret
+  , start
+
+  , tally = function (finish, err, avg) {
+      ret.push(avg)
+      if (ret.length == CHILDREN) {
+        let pi  = ret.reduce(function (a, b) { return a + b }) / ret.length
+          , end = +new Date()
+        console.log('π ≈', pi, '\t(' + Math.abs(pi - Math.PI), 'away from actual!)')
+        console.log('took', end - start, 'milliseconds')
+        if (finish)
+          finish()
+      }
+    }
+
+  , calc = function (method, callback) {
+      ret   = []
+      start = +new Date()
+      for (let i = 0; i < CHILDREN; i++)
+        method(POINTS_PER_CHILD, tally.bind(null, callback))
+    }
+
+console.log('Doing it the slow (single-process) way...')
+calc(calcDirect, function () {
+  console.log('Doing it the fast (multi-process) way...')
+  calc(calcWorker, process.exit)
+})