title: mpi process ids
body: <p>I would like to get the process ids of an mpi application which I start with mpirun/mpiexec tools.</p>
  
  <p>For example I run my code with lets say 8 processes and want to get the process ids of all these 8 processes right at the beginning of the execution to give to another tool as an input. </p>
  
  <p>What would be the right way to do this?</p>