.. _running-batch:

======================
Running a Batch Solver
======================

The "MFiX Batch Solver" refers to the command line version of MFiX including
MFiX 2016-1 and earlier versions. The "MFiX Interactive Solver" refers to all later
releases of MFiX. The batch solver binary is not installed in the MFiX conda package; it
needs to be compiled before being used (as in previous versions of MFiX).

Using the Batch Solver is appropriate when you do not want to use the
interactive features with the GUI. You cannot pause, unpause, stop, or monitor
status from the batch solver.

To build the batch solver see :ref:`build-batch`.


Running (Serial)
----------------

To run a serial instance of the MFiX solver, type:
.. code-block:: shell

    > ./mfixsolver -f DES_FB1.mfx


Running with DMP
----------------

If you built the solver :ref:`configured with DMP support <solver_configuration>`, then
you can run MPI jobs with the standard MPI wrapper command ``mpirun``. For
instance, to run using 4 cores with the domain divided along the X and Y
axes:

.. code-block:: shell

    > mpirun -np 4 ./mfixsolver -f DES_FB1.mfx NODESI=2 NODESJ=2

The number of MPI processes specified with ``-np`` must be equal to the product of the
keywords ``NODESI*NODESJ*NODESK``.

For further details on using ``mpirun``, see the documentation for the MPI implementation for your system.


Running with SMP
----------------

If you built the solver :ref:`configured with SMP support
<solver_configuration>`, then you can set the number of OpenMP threads using
the ``OMP_NUM_THREADS`` environment variable. For instance, to run with
four threads:

.. code-block:: shell

    > env OMP_NUM_THREADS=4 ./mfixsolver -f DES_FB1.mfx

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