===================== Environment Variables ===================== The following lists environment variables that can affect the way MESA runs. Essential --------- ``MESA_DIR`` ~~~~~~~~~~~~ Location of the MESA source code. ``GYRE_DIR`` ~~~~~~~~~~~~ Location of the GYRE source code (only needed if running GYRE separately from MESA). If you haven't moved it from the ``$MESA_DIR`` then set as ``GYRE_DIR=$MESA_DIR/build/gyre/src``. Recommended ----------- ``OMP_NUM_THREADS`` ~~~~~~~~~~~~~~~~~~~ Number of threads MESA will run with. Should be between 1 and 2 * number of logical cores. ``MESASDK_ROOT`` ~~~~~~~~~~~~~~~~ Location of the SDK. Optional -------- ``MESA_CACHES_DIR`` ~~~~~~~~~~~~~~~~~~~ Location where MESA will store and read cache files. See :ref:`star_job.defaults cache directories ` for more details. Beware when using this and changing MESA versions; best practice would be to remove its contents upon changing versions. ``MESA_TEMP_CACHES_DIR`` ~~~~~~~~~~~~~~~~~~~~~~~~ Location where MESA will write the cache file temporarily before moving to ``$MESA_CACHES_DIR``. If set, this folder MUST be unique for each MESA run. If not set defaults to ``./.mesa_temp_cache``. ``MESA_OP_MONO_DATA_PATH`` ~~~~~~~~~~~~~~~~~~~~~~~~~~ Location of the OP_MONO data files. See the :ref:`radiative levitation ` test suite (located in ``$MESA_DIR/star/test_suite/radiative_levitation/inlist_radiative_levitation``) for more details. ``MESA_INLIST`` ~~~~~~~~~~~~~~~ By default MESA will look for a file called ``inlist`` in the local working directory for its configuration. This overrides the filename and can point to a file somewhere else. ``MESA_FORCE_PGSTAR_FLAG`` ~~~~~~~~~~~~~~~~~~~~~~~~~~ If set, this shell variable will override the inlist variable ``pgstar_flag``. If set to either ``true`` or ``TRUE`` MESA will act as if the user had set ``pgstar_flag=.true.`` in their inlist. If set to either ``false`` or ``FALSE`` MESA will act as if the user had set ``pgstar_flag=.false.`` in their inlist. If set to anything else (or not set at all) MESA will use the value as set in the inlists. ``MESA_SKIP_OPTIONAL`` ~~~~~~~~~~~~~~~~~~~~~~ If set then when running a test_suite case, then certain optional inlists will be skipped. If not set, then all inlists will be run. Misc ---- Useful things that are not environment variables. Command line arguments ~~~~~~~~~~~~~~~~~~~~~~ ``./build/bin/star`` can accept one argument that overrides the location of the inlist file. This will also override the environment variable ``$MESA_INLIST``. :: ./build/bin/star some_other_inlist_file Private ------- These options are for developers; you do not need them for normal usage. If you use them and things break then stop using them. ``MESA_DIR_INTENTIONALLY_EMPTY`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Bypass checks done at compile time for checking if ``$MESA_DIR`` and ``MESAROOT_SDK`` is set. ``MESA_TEMP_CACHES_DISABLE`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If set, then we do not use the temp cache mechanism, writing cache files directly to the ``$MESA_DIR/data/`` folder. ``MESA_ERROR_BACKTRACE_DISABLE`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If set, disables the generation of backtraces when we call ``mesa_error()``. This is mostly helpful on macs, as they don't generate useful backtraces. ``MESA_FPE_CHECKS_ON`` ~~~~~~~~~~~~~~~~~~~~~~ When set to 1 this turns on certain inlist options designed to catch floating point exceptions. This should not be set during a normal run. ``MESA_TEST_SUITE_RESOLUTION_FACTOR`` ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ If set to a value other than 1, then ``mesh_delta_coeff`` and ``time_delta_coeff`` will be multiplied by its value, and ``max_model_number`` will be multiplied by its inverse. For example, this can be set to 0.5 to double the space and time resolution as well as the maximum model number. During a normal run, this should be either set to 1, or not set.