Machine Learning 4.2

answer.js

"// noprotect";
var a = function() {
  'use strict';

  var examples = [
  {inputs: {a: -1, b: -1}, output: -1},
  {inputs: {a: -1, b: 1}, output: -1},
  {inputs: {a: 1, b: -1}, output: 1},
  {inputs: {a: 1, b: 1}, output: -1},
  ];

  function train(examples) {
    var positive = 0,
        negative = 0,
        update = 0,
        n = 0.05,
        w0 = Math.random() * 2 - 1,
        w1 = Math.random() * 2 - 1,
        w2 = Math.random() * 2 - 1;
    for(var a = 0; a < 10000; a++) {
      var example = examples[Math.floor(Math.random() * examples.length)];

      var temp = (w0 + w1 * example.inputs.a + w2 * example.inputs.b);
      var o = temp > 0 ? 1 : -1;
      if(o == 1) { positive += 1; } else { negative += 1; }
      var deltaw0 = n * (example.output - o) * w0;
      var deltaw1 = n * (example.output - o) * w1;
      var deltaw2 = n * (example.output - o) * w2;
      w0 += deltaw0;
      w1 += deltaw1;
      w2 += deltaw2;
    }
    console.log('positive: ' + positive);
    console.log('negative: ' + negative);
    return {w0: w0, w1: w1, w2: w2};
  }

  var test = function(examples, weights) {
    var results = examples.map(function(example) {
      var temp = weights.w0 + weights.w1 * example.inputs.a + weights.w2 * example.inputs.b;
      var o = temp > 0 ? 1 : -1;
      console.log('example: ' + JSON.stringify(example) + ' result: ' + o);
      return example.output == o;
    });
    var result = results.reduce(function(i, sum) { return i & sum; });
    console.log('test result was: ' + result);
    return result;
  };

  var t = false,
      loopCounter = 0,
      goodWeights = [];
  while(!t) {
    loopCounter += 1;

    var weights = train(examples);
    console.log('weights: ' + JSON.stringify(weights));
    var testResult = test(examples, weights);
    if(testResult) {
      goodWeights.push(weights);
    }
    console.log('results of test ' + loopCounter + ': ' + testResult);
    if(loopCounter > 500) {
      t = true;
    }
  }
  console.log('succeeded ' + goodWeights.length + ' times');
  console.log(JSON.stringify(goodWeights));
}();