mpiexec -n <total ranks> ./mpi_test <total rows> <total cols> [<input file>]
The <input file> is an optional argument. If it's omitted, the input is taken from stdin.
mpiexec -n 10 ./mpi_test 300 200 input.txt
or
mpiexec -n 10 ./mpi_test 300 200
GET ROW 23
get aggr 95
exit