add comments for review of PR68

src/model.hpp

@@ -84,9 +84,15 @@ public:
     }
 
     time_type run(time_type tfinal, time_type dt) {
-        time_type min_delay = communicator_.min_delay()/2;
+        // Calculate the size of the largest possible time integration interval
+        // before communication of spikes is required.
+        // If spike exchange and cell update are serialized, this is the
+        // minimum delay of the network, however we use half this period
+        // to overlap communication and computation.
+        time_type t_interval = communicator_.min_delay()/2;
+
         while (t_<tfinal) {
-            auto tuntil = std::min(t_+min_delay, tfinal);
+            auto tuntil = std::min(t_+t_interval, tfinal);
 
             event_queues_.exchange();
             local_spikes_.exchange();

src/util/double_buffer.hpp

@@ -9,6 +9,7 @@ namespace nest {
 namespace mc {
 namespace util {
 
+/// double buffer with thread safe exchange/flip operation.
 template <typename T>
 class double_buffer {
 private:
@@ -26,27 +27,35 @@ public:
         index_(0)
     {}
 
+    /// remove the copy and move constructors which won't work with std::atomic
     double_buffer(double_buffer&&) = delete;
     double_buffer(const double_buffer&) = delete;
     double_buffer& operator=(const double_buffer&) = delete;
     double_buffer& operator=(double_buffer&&) = delete;
 
+    /// flip the buffers in a thread safe manner
+    /// n calls to exchange will always result in n flips
     void exchange() {
+        // use operator^= which is overloaded by std::atomic<>
         index_ ^= 1;
     }
 
+    /// get the current/front buffer
     value_type& get() {
         return buffers_[index_];
     }
 
+    /// get the current/front buffer
     const value_type& get() const {
         return buffers_[index_];
     }
 
+    /// get the back buffer
     value_type& other() {
         return buffers_[other_index()];
     }
 
+    /// get the back buffer
     const value_type& other() const {
         return buffers_[other_index()];
     }