Added missing files

src/main/java/net/echo/brain4j/training/updater/Updater.java

@@ -0,0 +1,20 @@
+package net.echo.brain4j.training.updater;
+
+import net.echo.brain4j.layer.Layer;
+import net.echo.brain4j.structure.Synapse;
+
+import java.util.List;
+
+public abstract class Updater {
+
+    public void postInitialize() {
+    }
+
+    public void postIteration(List<Layer> layers, double learningRate) {
+    }
+
+    public void postFit(List<Layer> layers, double learningRate) {
+    }
+
+    public abstract void acknowledgeChange(Synapse synapse, double change, double learningRate);
+}

src/main/java/net/echo/brain4j/training/updater/impl/NormalUpdater.java

@@ -0,0 +1,50 @@
+package net.echo.brain4j.training.updater.impl;
+
+import net.echo.brain4j.layer.Layer;
+import net.echo.brain4j.structure.Neuron;
+import net.echo.brain4j.structure.Synapse;
+import net.echo.brain4j.training.updater.Updater;
+
+import java.util.Arrays;
+import java.util.List;
+
+public class NormalUpdater extends Updater {
+
+    private Synapse[] synapses;
+    private Double[] gradients;
+    private int minSynapseIndex;
+
+    @Override
+    public void postInitialize() {
+        this.synapses = new Synapse[Synapse.ID_COUNTER];
+        this.gradients = new Double[Synapse.ID_COUNTER];
+        Arrays.fill(gradients, 0.0);
+    }
+
+    @Override
+    public void postFit(List<Layer> layers, double learningRate) {
+        for (int i = 0; i < gradients.length; i++) {
+            Synapse synapse = synapses[i];
+            double gradient = gradients[i];
+
+            synapse.setWeight(synapse.getWeight() + learningRate * gradient);
+        }
+
+        for (Layer layer : layers) {
+            for (Neuron neuron : layer.getNeurons()) {
+                double deltaBias = learningRate * neuron.getDelta();
+                neuron.setBias(neuron.getBias() + deltaBias);
+            }
+        }
+
+        Arrays.fill(gradients, 0.0);
+    }
+
+    @Override
+    public void acknowledgeChange(Synapse synapse, double change, double learningRate) {
+        int id = synapse.getSynapseId();
+
+        synapses[id] = synapse;
+        gradients[id] += change;
+    }
+}

src/main/java/net/echo/brain4j/training/updater/impl/StochasticUpdater.java

@@ -0,0 +1,26 @@
+package net.echo.brain4j.training.updater.impl;
+
+import net.echo.brain4j.layer.Layer;
+import net.echo.brain4j.structure.Neuron;
+import net.echo.brain4j.structure.Synapse;
+import net.echo.brain4j.training.updater.Updater;
+
+import java.util.List;
+
+public class StochasticUpdater extends Updater {
+
+    @Override
+    public void postIteration(List<Layer> layers, double learningRate) {
+        for (Layer layer : layers) {
+            for (Neuron neuron : layer.getNeurons()) {
+                double deltaBias = learningRate * neuron.getDelta();
+                neuron.setBias(neuron.getBias() + deltaBias);
+            }
+        }
+    }
+
+    @Override
+    public void acknowledgeChange(Synapse synapse, double change, double learningRate) {
+        synapse.setWeight(synapse.getWeight() + change);
+    }
+}