bayesian-bandit - npm Package Compare versions

Comparing version 0.9.1 to 0.10.0

bayesian-bandit.js

@@ -9,8 +9,19 @@ (function(exports) {
 
-  function Arm() { }
+  /**
+   * @param {object} [args]
+   * @param {int} [args.count] - number of attempts on this arm
+   * @param {number} [args.sum] - total value accumulated on this arm
+   * @constructor
+     */
+  function Arm(args) {
+    this.count = args && args.count || 0
+    this.sum = args && args.sum || 0
+  }
 
-  Arm.prototype.count = 0
-
-  Arm.prototype.sum = 0
-
+  /**
+   * @param {number} value
+   *
+   * Increments number of attempts on the arm by one and the total accumulated
+   * value by value
+   */
   Arm.prototype.reward = function(value) {
@@ -22,2 +33,17 @@
 
+  /**
+   * @param {int} numTries
+   * @param {number} totalValue
+   *
+   * Increments the number of attempts on the arm and the total value
+   * accumulated during those attempts.
+   */
+  Arm.prototype.rewardMultiple = function(numTries, totalValue) {
+    this.count += numTries
+    this.sum += totalValue
+  }
+
+  /**
+   * @returns {number} between 0 and 1
+   */
   Arm.prototype.sample = function() {
@@ -27,15 +53,20 @@ return this.rbeta(1 + this.sum, 1 + this.count - this.sum)
 
+  /**
+   * @param {int} a
+   * @param {int} b
+   * @returns {number} - number between 0 and 1
+   *
+   * Adapted from https://github.com/CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers/master/Chapter6_Priorities/d3bandits.js,
+   * which references Simulation and MC, Wiley.
+   *
+   * This apparently generates random numbers from a beta distribution:
+   * http://en.wikipedia.org/wiki/Beta_distribution
+   * I don't really know why this works -- it's just adapted from d3bandits.js
+   *
+   * For comparison, you might want to review the R project's rbeta code:
+   * https://svn.r-project.org/R/trunk/src/nmath/rbeta.c
+   *
+   */
   Arm.prototype.rbeta = function(a, b) {
 
-    // Adapted from https://github.com/CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers/master/Chapter6_Priorities/d3bandits.js,
-    // which references Simulation and MC, Wiley.
-    //
-    // This apparently generates random numbers from a beta distribution:
-    // http://en.wikipedia.org/wiki/Beta_distribution
-    // I don't really know why this works
-    // -- it's just adapted from d3bandits.js.
-    //
-    // For comparison, you might want to review the R project's rbeta code:
-    // https://svn.r-project.org/R/trunk/src/nmath/rbeta.c
-
     var sum = a + b
@@ -72,2 +103,16 @@ , ratio = a / b
 
+  /**
+   * @param {object} [options]
+   * @param {Array.<{count: int, sum: number}>} [options.arms]
+   *      - Initialize the bandit with arms specified by the data provided
+   *
+   * @param {int} [options.numberOfArms]
+   *      - Initialize the bandit with a number of empty arms
+   *
+   * Note, only one of options.arms and options.numberOfArms should
+   * be provided.  If both are provided, options.arms takes precedence and
+   * numberOfArms will be ignored.
+   *
+   * @constructor
+     */
   function Bandit(options) {
@@ -77,7 +122,17 @@
 
-    for(var a = 0; a < (options || {}).numberOfArms; a++) {
-      this.arms.push(new Arm())
+    // If options.arms is explicitly passed, initialize the arms array with it
+    if (options && options.arms) {
+      for (var i = 0; i < options.arms.length; i++) {
+        this.arms.push(new Arm(options.arms[i]))
+      }
+    } else { // Otherwise initialize empty arms based on options.numberOfArms
+      for (var a = 0; a < (options || {}).numberOfArms; a++) {
+        this.arms.push(new Arm())
+      }
     }
   }
 
+  /**
+   * @returns {int} - index of the arm chosen by the bandit algorithm
+   */
   Bandit.prototype.selectArm = function() {
@@ -84,0 +139,0 @@

package.json

 {
   "name": "bayesian-bandit",
-  "version": "0.9.1",
+  "version": "0.10.0",
   "description": "Bayesian bandit implementation for Node and the browser.",
@@ -10,2 +10,5 @@ "main": "./bayesian-bandit.js",
   },
+  "scripts": {
+    "test": "nodeunit tests.js"
+  },
   "keywords": [
@@ -29,3 +32,6 @@ "machine",
   },
-  "author": "omphalos"
+  "author": "omphalos",
+  "devDependencies": {
+    "nodeunit": "^0.9.1"
+  }
 }

tests.js

@@ -31,2 +31,14 @@ var testCase = require('nodeunit').testCase
 
+    'rewardMultiple should increase the sum and count': function(test) {
+
+      var arm = new Bandit.Arm()
+
+      arm.rewardMultiple(10, 2)
+      arm.rewardMultiple(15, 5)
+
+      test.equal(arm.count, 25)
+      test.equal(arm.sum, 7)
+      test.done()
+    },
+
     'sample should sample from the rbeta distribution': function(test) {
@@ -142,2 +154,24 @@
 
+    'new Bandit with options.arms should initialized arms properly': 
+        function(test) {
+
+      var bandit = new Bandit({
+        arms:[
+          {count: 100, sum: 20},
+          {count: 50,  sum: 30},
+          {count: 70,  sum: 10}
+        ]
+      })
+
+      test.equal(bandit.arms.length, 3)
+      test.equal(bandit.arms[0].count, 100)
+      test.equal(bandit.arms[0].sum, 20)
+      test.equal(bandit.arms[1].count, 50)
+      test.equal(bandit.arms[1].sum, 30)
+      test.equal(bandit.arms[2].count, 70)
+      test.equal(bandit.arms[2].sum, 10)
+      test.done()
+
+    },
+
     'selectArm should return the arm with the largest sample': function(test) {
@@ -144,0 +178,0 @@

No alert changes

Improved metrics

Total package byte prevSize

13439

increased by32.4%

Number of package files

6

increased by20%

Lines of code

302

increased by37.9%

Number of lines in readme file

61

increased by38.64%

Worsened metrics

Dev dependency count

1

increased byInfinity%

No dependency changes