From 3f5e5f4ce737328ce77d30234d19650ddebcc8f0 Mon Sep 17 00:00:00 2001
From: "Eric L. Solis" <elopez@getinsoft.com>
Date: Thu, 26 Nov 2020 15:44:40 +0000
Subject: [PATCH] Add method to distribute array of weight references into
 network's neurons

---
 src/ai/ann/Layer.js   |  7 +++++++
 src/ai/ann/Network.js | 23 +++++++++++++++++++----
 src/ai/ann/Neuron.js  |  6 +++++-
 src/ai/ann/math.js    | 10 +++++++++-
 4 files changed, 40 insertions(+), 6 deletions(-)

diff --git a/src/ai/ann/Layer.js b/src/ai/ann/Layer.js
index 08785ce..1fd0086 100644
--- a/src/ai/ann/Layer.js
+++ b/src/ai/ann/Layer.js
@@ -1,3 +1,4 @@
+const { chunk } = require('lodash');
 const { Neuron } = require('./Neuron');
 
 function Layer([size, activation]) {
@@ -5,11 +6,17 @@ function Layer([size, activation]) {
     neurons: Array.from(Array(size)).map(_ => Neuron(1, activation)),
     error: Infinity,
     predict,
+    distributeWights,
   };
   function predict(inputs) {
     layer.output = layer.neurons.map(neuron => neuron.predict(inputs));
     return layer.output;
   }
+  function distributeWights(weights) {
+    chunk(weights, weights.length / layer.neurons.length).forEach((weightChunk, i) => {
+      layer.neurons[i].weights = weightChunk;
+    });
+  }
   return layer;
 }
 
diff --git a/src/ai/ann/Network.js b/src/ai/ann/Network.js
index 914ec5d..6a973a0 100644
--- a/src/ai/ann/Network.js
+++ b/src/ai/ann/Network.js
@@ -1,11 +1,12 @@
 const { Layer } = require('./Layer');
-const { delta, mse } = require('./math');
-const { sum } = require('lodash');
+const { delta, mse, weightsForArchitecture } = require('./math');
+const { sum, times } = require('lodash');
 
 function Network(layerDescriptors, learningRate = 0.5) {
   let layers = [];
   let trainingData = [];
-  layers = layerDescriptors.map(Layer);
+  layers = layerDescriptors.slice(1).map(Layer);
+  const architecture = layerDescriptors.map(([n]) => n);
 
   const network = {
     layers,
@@ -14,7 +15,16 @@ function Network(layerDescriptors, learningRate = 0.5) {
     trainingData,
     train,
     converges,
+    distributeWights,
   };
+  function distributeWights(weightObjects) {
+    let offset = 0;
+    for (let i = 1; i < architecture.length; i++) {
+      const currentLayerWeightCount = architecture[i] * (architecture[i - 1] + 1);
+      layers[i - 1].distributeWights(weightObjects.slice(offset, offset + currentLayerWeightCount));
+      offset += currentLayerWeightCount;
+    }
+  }
 
   function forward(inputs) {
     const layerOutputs = [layers[0].predict(inputs)];
@@ -63,11 +73,16 @@ function Network(layerDescriptors, learningRate = 0.5) {
 
 const network = Network(
   [
+    [2],
     [3, 'sigmoid'],
     [1, 'sigmoid'],
   ],
   0.9,
 );
+const problemSize = weightsForArchitecture([2, 3, 1]);
+const weights = times(problemSize, () => ({ value: Math.random() }));
+network.distributeWights(weights);
+
 const inputs = [
   [0, 0],
   [0, 1],
@@ -90,7 +105,7 @@ while (!network.converges(0.1)) {
         .join(','),
     )
     .join(';');
-  if (i == 1000) {
+  if (i == 10000) {
     console.log(actualOutputs);
     console.log(network.error);
     i = 0;
diff --git a/src/ai/ann/Neuron.js b/src/ai/ann/Neuron.js
index 85493ce..38eacfe 100644
--- a/src/ai/ann/Neuron.js
+++ b/src/ai/ann/Neuron.js
@@ -20,8 +20,8 @@ function Neuron(inputQuantity = 1, type = 'linear') {
   }
 
   function predict(inputs) {
+    fill(inputs.length);
     inputs = [...inputs, -1];
-    while (inputs.length > neuron.weights.length) neuron.weights.push({ value: Math.random() });
     neuron.inputs = inputs;
     neuron.output = activations[type].function(_predict(inputs));
 
@@ -34,6 +34,10 @@ function Neuron(inputQuantity = 1, type = 'linear') {
     }
   }
 
+  function fill(inputsLength) {
+    while (inputsLength >= neuron.weights.length) neuron.weights.push({ value: Math.random() });
+  }
+
   return neuron;
 }
 
diff --git a/src/ai/ann/math.js b/src/ai/ann/math.js
index 7722664..edf4b8f 100644
--- a/src/ai/ann/math.js
+++ b/src/ai/ann/math.js
@@ -66,4 +66,12 @@ const activations = {
   },
 };
 
-module.exports = { dot, activations, mse };
+function weightsForArchitecture(arch) {
+  let sum = 0;
+  for (let i = 0; i < arch.length - 1; i++) {
+    sum += (arch[i] + 1) * arch[i + 1];
+  }
+  return sum;
+}
+
+module.exports = { dot, activations, mse, weightsForArchitecture };