Quick Reference: OpenMDAO-Related Environment Variables

In some cases, the way in which OpenMDAO operates is up to the preferences of the user. At this time, rather than using a preferences file, these optional OpenMDAO behaviors are based on the values of environment variables.

Some of these environment variables are interpreted as either being “truthy” or “falsey”. For OpenMDAO, an environment variable is considered False if it takes on one of the following values:

• ‘0’

• ‘false’

• ‘no’

• ‘off’

• ‘none’

• ‘’

These are all string values and OpenMDAO interprets them in a case-insensitive way. Note that, for OpenMDAO, the empty string means that an unset environment variable will be interpreted as False.

Any other environment variable value other than those above is interpreted as True.

User-Facing Environment Variables

Environment Variable	Description	See Also
OPENMDAO_INVALID_DESVAR_BEHAVIOR	Specifies default driver behavior if the initial design variables are out of bounds.	Paraboloid
OPENMDAO_REPORTS	May be boolean-like or the names of the desired reports to be generated.	Reports
OPENMDAO_USE_MPI	Set to True to force an exception when MPI is needed but mpi4py is unavailable.	Controlling MPI
OPENMDAO_WORKDIR	Top-level directory for OpenMDAO outputs. Defaults to current working directory if not set.	Reports System
USE_PROC_FILES	Set to True to cause stdout/err from each MPI process to be written to [rank].out.	Controlling MPI
OMPI_MCA_rmaps_base_oversubscribe	Set to ‘1’ to fix there are not enough slots available in the system issue for some versions of MPI.	Controlling MPI
OMPI_MCA_btl=self,tcp	Set to ‘self,tcp’ to fix A system call failed during shared memory initialization that should not have… error in some version of MPI	Controlling MPI