code: function altersingle(alpha, i, b, g, r) {
  
      /* alter hit neuron */
      var n = network[i];
      n[0] -= (alpha * (n[0] - b)) / initalpha;
      n[1] -= (alpha * (n[1] - g)) / initalpha;
      n[2] -= (alpha * (n[2] - r)) / initalpha;
    }
docs: /*
  Move neuron i towards biased (b,g,r) by factor alpha
  ----------------------------------------------------