Write a program to measure the time it takes to send 1, 2, 4, ..., 1M C
doubles from one processor to another using MPI_Ssend and MPI_Recv. Use the
same techniques as in the memcpy assignment to average out variations and
overhead in MPI_Wtime.
Print the size, time, and rate in MB/sec for each test.
Make sure that both sender and reciever are ready when you begin the test.
The sample solution uses MPI_Sendrecv, but other choices are possible.