sligthly improved efficiency (~2.5 sec)

lib/nBodySim.cpp

@@ -68,7 +68,7 @@ void nBodySim::calculateForces() {
         forces_[i] = 0.0;
     }
     // loop over each pair of particles and calculate the force between them
-    #pragma omp parallel for schedule(guided)
+    #pragma omp parallel for // schedule(guided)
     for (unsigned i = 0; i < nParticles_; i++) {
         double mi = masses_[i];
         double s = softening_[i];

main.cpp

@@ -36,7 +36,8 @@ int main(int argc, char** argv) {
 
     try {
         auto start = std::chrono::high_resolution_clock::now();
-        sim.calculateForces();
+        // for (unsigned i=0; i<100; ++i)
+            sim.calculateForces();
         auto stop = std::chrono::high_resolution_clock::now();
 
         auto duration = std::chrono::duration_cast<std::chrono::microseconds>(stop - start);