MPI_INFO_ENV(3) Open MPI MPI_INFO_ENV(3)

MPI_INFO_ENV - Static MPI_Info object containing info about the application

The MPI-3 standard established a static MPI_Info object named MPI_INFO_ENV that can be used to access information about how the application was executed from the run-time.

If available, the value will be set to argv[0]. Note that the value may not always be available - e.g., it is valid for a program to call MPI_Init with NULL parameters, in which case argv[0] will not be set if run as a singleton. This value will never be set in a Fortran program as the argv are not available.
The argv given for the application. If no arguments are passed to the application, then this value will not be set. It will also not be set in the case of a singleton that calls MPI_Init with NULL parameters, or a Fortran program.
The number of processes in the job.
Open MPI does not support the soft option for specifying the number of processes to be executed, so this value is set to the same as maxprocs.
The name of the host this process is executing upon - the value returned from gethostname().
The architecture of the host this process is executing upon. This value indicates the underlying chip architecture (e.g., x86_64), if it can be determined.
The working directory at the time of process launch by mpiexec. Note that this value will not be set for processes launched as singletons as there is no reliable way for the MPI library to determine the location.
Although specified by the MPI-3 standard, no value is currently set for this field.
The requested MPI thread level - note that this may differ from the actual MPI thread level of the application.
The number of application contexts in an MPMD job. This is an Open MPI-specific field and value.
The number of processes in each application context, provided as a space-delimited list of integers. This is an Open MPI-specific field and value.
The MPI rank of the first process in each application context, provided as a space-delimited list of integers This is an Open MPI-specific field and value.
If Open MPI was asked to pre-position files, this field provides the top-level directory where those files were place. This is an Open MPI-specific field and value.

When calling MPI_INFO_GET(3), the flag parameter will be set to zero (false) if a value for the field has not been set.

MPI_Info_get

November 24, 2021 4.1.2