From e6ab4a8ed100d5d5b7611c74cf3ccd556f1f1d71 Mon Sep 17 00:00:00 2001
From: Paul Oliver <contact@pauloliver.dev>
Date: Thu, 29 Feb 2024 19:04:34 +0100
Subject: Initial commit

---
 src/NoveltyMetric.cpp | 101 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 src/NoveltyMetric.cpp

(limited to 'src/NoveltyMetric.cpp')

diff --git a/src/NoveltyMetric.cpp b/src/NoveltyMetric.cpp
new file mode 100644
index 0000000..dd40118
--- /dev/null
+++ b/src/NoveltyMetric.cpp
@@ -0,0 +1,101 @@
+#include <algorithm>
+#include <Hyperneat/Population.hpp>
+#include <Hyperneat/NoveltyMetric.hpp>
+
+using namespace std;
+using namespace hyperneat;
+
+const NoveltyMetricPrms&
+NoveltyMetric::getPrms() const
+{
+    return _prms;
+}
+
+const Vector<Behavior>&
+NoveltyMetric::getBehaviors() const
+{
+    return _behaviors;
+}
+
+const Vector2D<double>&
+NoveltyMetric::getArchive() const
+{
+    return _archive;
+}
+
+Behavior&
+NoveltyMetric::getBehaviorOf(size_t i)
+{
+    return _behaviors[i];
+}
+
+void
+NoveltyMetric::initialize(const NoveltyMetricPrms& prms, Population* population)
+{
+    _prms = prms;
+    _behaviors.resize(population->getAllOrganisms().size());
+
+    for (size_t i = 0; i < _behaviors.size(); ++i) {
+        population->getOrganism(i)._behavior = &_behaviors[i];
+        _behaviors[i]._organism              = &population->getOrganism(i);
+        _behaviors[i]._noveltyMetric         = this;
+        _behaviors[i]._criteriaReached       = prms._criteriaReachedByDefault;
+        _behaviors[i]._characterization.resize(prms._characterizationSize, 0.0);
+    }
+}
+
+void
+NoveltyMetric::setScores()
+{
+    size_t readyOrganisms = 0;
+
+    for (auto& i : _behaviors) {
+        if ((i._isReady = (i._organism->isOld() && i._criteriaReached))) {
+            ++readyOrganisms;
+        }
+    }
+
+    for (auto& i : _behaviors) {
+        if (!i._isReady) {
+            i._toBeArchived       = false;
+            i._organism->_fitness = i._noveltyScore = 0.0;
+            continue;
+        }
+
+        Vector<double> distances;
+        distances.reserve(readyOrganisms + _archive.size() - 1);
+
+        for (auto& j : _behaviors) {
+            if (j._isReady && (&i != &j)) {
+                distances.emplace_back(getDistance(i._characterization, j._characterization));
+            }
+        }
+
+        for (auto& j : _archive) {
+            distances.emplace_back(getDistance(i._characterization, j));
+        }
+
+        auto dEnd = distances.end();
+        auto dBeg = distances.begin();
+        auto dRef = dBeg + _prms._referenceOrganisms;
+
+        partial_sort(dBeg, dRef, dEnd);
+
+        double totalDistance  = accumulate(dBeg, dRef, 0.0);
+        i._organism->_fitness = i._noveltyScore = (totalDistance / static_cast<double>(_prms._referenceOrganisms));
+        i._toBeArchived       = (i._noveltyScore > _prms._noveltyThreshold);
+    }
+}
+
+double
+NoveltyMetric::getDistance(const Vector<double>& v1, const Vector<double>& v2) const
+{
+    double result = 0.0;
+
+    for (size_t i = 0; i < v1.size(); ++i) {
+        double diff = v1[i] - v2[i];
+        result     += diff * diff;
+    }
+
+    return sqrt(result);
+}
-- 
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