Connections: introduce Random rng_ member

and use it for synapsesCompetition()

src/htm/algorithms/Connections.cpp

@@ -53,6 +53,8 @@ void Connections::initialize(CellIdx numCells, Permanence connectedThreshold, bo
   connectedThreshold_ = connectedThreshold - htm::Epsilon;
   iteration_ = 0;
 
+  rng_ = Random(42); //TODO set the seed
+
   nextEventToken_ = 0;
 
   timeseries_ = timeseries;
@@ -476,7 +478,8 @@ void Connections::adaptSegment(const Segment segment,
   }
 
   //balance synapses using competition on dendrite
-  synapseCompetition(segment, 4, 10); //FIXME derive these numbers
+  if(rng_.getReal64() < 0.01f) //1% chance //TODO set the probability?
+    synapseCompetition(segment, 4, 10); //FIXME derive these numbers
 
   //destroy segment if it has too few synapses left -> will never be able to connect again
   if(pruneZeroSynapses and synapses.size() < connectedThreshold_) {

src/htm/algorithms/Connections.hpp

@@ -33,6 +33,7 @@
 #include <htm/types/Types.hpp>
 #include <htm/types/Serializable.hpp>
 #include <htm/types/Sdr.hpp>
+#include <htm/utils/Random.hpp>
 
 namespace htm {
 
@@ -715,9 +716,9 @@ class Connections : public Serializable
   std::vector<Synapse>     destroyedSynapses_;
   Permanence               connectedThreshold_; //TODO make const
   UInt32 iteration_ = 0;
+  Random rng_;
 
   // Extra bookkeeping for faster computing of segment activity.
-
   struct identity { constexpr size_t operator()( const CellIdx t ) const noexcept { return t; };   };	//TODO in c++20 use std::identity 
 
   std::unordered_map<CellIdx, std::vector<Synapse>, identity> potentialSynapsesForPresynapticCell_;