Merge branch 'get_earliest_pixel' into 'master'

Cluster: add function to retrieve earliest pixel + split getSeedPixel()

See merge request !433

src/objects/Cluster.cpp

@@ -51,41 +51,41 @@ std::vector<const Pixel*> Cluster::pixels() const {
 const Pixel* Cluster::getSeedPixel() const {
     Pixel* seed = nullptr;
 
-    // If cluster has non-zero charge, return pixel with largest charge,
-    // else return earliest pixel.
     double maxcharge = -1;
-    // If charge != 0 (use epsilon to avoid errors in floating-point arithmetic):
-    if(m_charge > std::numeric_limits<double>::epsilon()) {
-        // loop overall pixels and find the one with the largest charge:
-        for(auto& px : m_pixels) {
-            auto pxl = dynamic_cast<Pixel*>(px.GetObject());
-            if(pxl == nullptr) {
-                throw MissingReferenceException(typeid(*this), typeid(Pixel));
-            }
-
-            if(pxl->charge() > maxcharge) {
-                maxcharge = pxl->charge();
-                seed = pxl;
-            }
+    // loop overall pixels and find the one with the largest charge:
+    for(auto& px : m_pixels) {
+        auto pxl = dynamic_cast<Pixel*>(px.GetObject());
+        if(pxl == nullptr) {
+            throw MissingReferenceException(typeid(*this), typeid(Pixel));
         }
-    } else { // return the earliest pixel:
-        double earliestTimestamp = std::numeric_limits<double>::max();
-        for(auto& px : m_pixels) {
-            auto pxl = dynamic_cast<Pixel*>(px.GetObject());
-            if(pxl == nullptr) {
-                throw MissingReferenceException(typeid(*this), typeid(Pixel));
-            }
-
-            if(pxl->timestamp() < earliestTimestamp) {
-                earliestTimestamp = pxl->timestamp();
-                seed = pxl;
-            }
+
+        if(pxl->charge() > maxcharge) {
+            maxcharge = pxl->charge();
+            seed = pxl;
         }
     }
-
     return seed;
 }
 
+const Pixel* Cluster::getEarliestPixel() const {
+    Pixel* earliest = nullptr;
+
+    double earliestTimestamp = std::numeric_limits<double>::max();
+    for(auto& px : m_pixels) {
+        auto pxl = dynamic_cast<Pixel*>(px.GetObject());
+        if(pxl == nullptr) {
+            throw MissingReferenceException(typeid(*this), typeid(Pixel));
+        }
+
+        if(pxl->timestamp() < earliestTimestamp) {
+            earliestTimestamp = pxl->timestamp();
+            earliest = pxl;
+        }
+    }
+
+    return earliest;
+}
+
 void Cluster::print(std::ostream& out) const {
     out << "Cluster " << this->m_local.x() << ", " << this->m_local.y() << ", " << this->m_global << ", " << this->m_charge
         << ", " << this->m_split << ", " << this->m_pixels.size() << ", " << this->m_columnWidth << ", " << this->m_rowWidth

src/objects/Cluster.hpp

@@ -67,12 +67,19 @@ namespace corryvreckan {
         /**
          * @brief Retrieve the seed pixel of the cluster.
          *
-         * The seed pixel is defined as the one with the highest charge. In case all pixels have zero charge, return the
-         * pixel with the earliest timestamp..
+         * The seed pixel is defined as the one with the highest charge. In case all pixels have the same charge return a
+         * random pixel.
          *
          * @return Seed pixel of the cluster
          */
         const Pixel* getSeedPixel() const;
+        /**
+         * @brief Retrieve the earliest pixel of the cluster.  In case all pixels have the same timstamp return a random
+         * pixel.
+         *
+         * @return Earliest pixel of the cluster
+         */
+        const Pixel* getEarliestPixel() const;
 
         // Set cluster parameters
         void setColumn(double col) { m_column = col; }
@@ -108,7 +115,7 @@ namespace corryvreckan {
         std::map<int, bool> m_columnHits;
 
         // ROOT I/O class definition - update version number when you change this class!
-        ClassDefOverride(Cluster, 12)
+        ClassDefOverride(Cluster, 13)
     };
 
     // Vector type declaration