MPI sorter with buffers, missing SnowPlow technique

MPI_basic/Barrier/Barrier.cpp

@@ -0,0 +1,30 @@
+#include <mpi.h>
+#include <iostream>
+#include <unistd.h>
+
+int main(int argc, char* argv[])
+{
+    double start, end;
+
+    MPI_Init(&argc, &argv);   //Initialize the MPI environment //TODO perche qui non (NULL, NULL) ??
+
+    int world_size;
+    MPI_Comm_size(MPI_COMM_WORLD, &world_size);    //Get the number of processes
+
+    int world_rank;
+    MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);    //Get the number of process
+
+    MPI_Barrier(MPI_COMM_WORLD);
+    start = MPI_Wtime();                            //Microsecond precision. Can't use time(), because each process will have a different "zero" time
+
+    sleep(30);
+
+    MPI_Barrier(MPI_COMM_WORLD);
+    end = MPI_Wtime();
+
+    if(world_rank == 0)
+        std::cout << "Process (rank " << world_rank+1 << "/" << world_size << "): time of work is " << end-start << "seconds" << std::endl;
+
+    MPI_Finalize(); //Clean up the MPI environment
+    return 0;
+}