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1. Write a program to measure the time it takes to perform an MPI_Allreduce on MPI_COMM_WORLD. Use a single MPI_DOUBLE as the in and out arguments. Use a loop to run for many times to average out variations and overhead in MPI_Wtime. Print the size of MPI_COMM_WORLD and time for each test. Make sure that both sender and reciever are ready when you begin the test.
2. How does the performance of MPI_Allreduce vary with the size of MPI_COMM_WORLD?
Complete the arguments of the MPI_Allreduce in the following pseudo code Choose either one of the following Fortran or C example