:term:`CFOUR_OMP_NUM_THREADS <CFOUR_OMP_NUM_THREADS (CFOUR)>`
"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""

      Sets the OMP_NUM_THREADS environment variable before calling CFOUR. If the environment variable :envvar:`OMP_NUM_THREADS` is set prior to calling Psi4 then that value is used. When set, this option overrides everything. Be aware the ``-n`` command-line option described in section :ref:`sec:threading` does not affect CFOUR. 

      * **Type**: integer
      * **Default**: 1