ADD calculating run time (Tcomm + Tcomp)

src/main/java/org/example/MPI_AVG.java

@@ -7,6 +7,10 @@ public class MPI_AVG {
     public static void main(String[] args) throws Exception {
         MPI.Init(args);
 
+        // Ensure all processes are ready before starting the clock
+        MPI.COMM_WORLD.Barrier();
+        long startTime = System.nanoTime();
+
         int rank = MPI.COMM_WORLD.Rank();
         int size = MPI.COMM_WORLD.Size();
 
@@ -76,6 +80,14 @@ public class MPI_AVG {
             System.out.println("========================================\n");
         }
 
+        MPI.COMM_WORLD.Barrier();
+        long endTime = System.nanoTime();
+
+        if (rank == 0) {
+            double duration = (endTime - startTime) / 1_000_000.0;
+            System.out.println("Execution Time for " + size + " processes: " + duration + " ms");
+        }
+
         MPI.Finalize();
     }
 }
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