Added comparision table

MatrixAvg.c

@@ -46,13 +46,18 @@ int main(int argc, char** argv) {
     MPI_Scatterv(X, counts, displs, MPI_INT, local_X, local_size, MPI_INT, 0, MPI_COMM_WORLD);
 
     // Print received elements
-    
     printf("Process %d received: ", world_rank);
     for (int i = 0; i < local_size; i++)
         printf("%d ", local_X[i]);
     printf("\n");
 
-    // Compute local average
+   
+    // barrier is used to make sure all processes start timing at the same moment
+    MPI_Barrier(MPI_COMM_WORLD);
+    double start_time = MPI_Wtime();
+   
+
+    // compute local average
     double local_sum = 0;
     for (int i = 0; i < local_size; i++)
         local_sum += local_X[i];
@@ -67,9 +72,17 @@ int main(int argc, char** argv) {
     double global_sum = 0;
     MPI_Reduce(&local_sum, &global_sum, 1, MPI_DOUBLE, MPI_SUM, 0, MPI_COMM_WORLD);
 
+   
+    // barrier ensures all processes finish computation before stopping timer
+    MPI_Barrier(MPI_COMM_WORLD);
+    double end_time = MPI_Wtime();
+    // ----------------------------------------------------------
+
     if (world_rank == 0) {
         double global_avg = global_sum / N;
         printf("Global average = %f\n", global_avg);
+        printf("Execution time with %d processes = %f seconds\n",
+               world_size, end_time - start_time);
     }
 
     free(local_X);

Note.txt

+Notice how increasing the number of processes make the program slower and that is because 
+Tcomm time is big compared to the array size.
+
+to take advantage of this we should make the array bigger then we can notice the difference and speed up 
+
+
+we also notice we make more processes then the number of cores in the system the program gets way slower.

preformanceCompare.tex

+\documentclass{article}
+
+\begin{document}
+
+\begin{table}[h]
+\centering
+\caption{Execution Time with Different Numbers of Processes}
+\begin{tabular}{|c|c|}
+\hline
+\textbf{Number of Processes} & \textbf{Execution Time (s)} \\
+\hline
+1 & 0.000014 \\
+\hline
+2 & 0.000052 \\
+\hline
+4 & 0.000062 \\
+\hline
+8 & 0.000184 \\
+\hline
+10 & 0.000651 \\
+\hline
+\end{tabular}
+\label{tab:time}
+\end{table}
+
+\end{document}
+