Input and Output

When MPI is used on more than one process ( $\var{nn} \cdot \var{np}>1$ ) no input from the standard input is accepted. Standard output on any process other than the master process (rank=0) will not be available. Error output from any processor will be redirected to the node where run-escript has been invoked. If the -o or ESCRIPT_STDFILES is set, then the standard and error output from any process other than the master process will be written to files of the names stdout_r.out and stderr_r.out (where r is the rank of the process).

If files are created or read by individual MPI processes with information local to the process (e.g in the dump function) and more than one process is used ( $\var{nn} \cdot \var{np}>1$ ), the MPI process rank is appended to the file names. This will avoid problems if processes are using a shared file system. Files which collect data which are global for all MPI processors will be created by the process with MPI rank 0 only. Users should keep in mind that if the file system is not shared, then a file containing global information which is read by all processors needs to be copied to the local file system before run-escript is invoked.