From 8eebf1079fbed2848ee47cf990f5def5926a0c1f Mon Sep 17 00:00:00 2001
From: Justin Wernick <justin@worthe-it.co.za>
Date: Tue, 19 Apr 2022 21:24:15 +0200
Subject: Refile for merging repos

---
 2015-spacebot/src/brain/neuron.cpp | 40 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 2015-spacebot/src/brain/neuron.cpp

(limited to '2015-spacebot/src/brain/neuron.cpp')

diff --git a/2015-spacebot/src/brain/neuron.cpp b/2015-spacebot/src/brain/neuron.cpp
new file mode 100644
index 0000000..c7dba2c
--- /dev/null
+++ b/2015-spacebot/src/brain/neuron.cpp
@@ -0,0 +1,40 @@
+#include "brain/neuron.h"
+#include <cmath>
+
+double Neuron::sigmoid(double input) const
+{
+    const double slope = 4.924273;
+    return (1/(1+(std::exp(-(slope*input)))));
+}
+
+bool Neuron::calculateActivation()
+{
+    double newActivation = 0;
+    for (auto const& link : _inputLinks)
+    {
+        newActivation += link.weightedActivation();
+    }
+    newActivation = sigmoid(newActivation);
+
+    const double errorMargin = 0.000001;
+    bool activationChanged = std::abs(newActivation - _activation) > errorMargin;
+    _activation = newActivation;
+    return activationChanged;
+}
+
+void Neuron::addInput(NeuralLink&& link)
+{
+    _inputLinks.push_back(std::move(link));
+}
+
+bool Neuron::hasInputWithWeight(std::string srcIdentifier, double weight) const
+{
+    for (auto const& link : _inputLinks)
+    {
+        if (link.inputIdentifier() == srcIdentifier && link.weight() == weight)
+        {
+            return true;
+        }
+    }
+    return false;
+}
-- 
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