Create a Pool of MAPDL Instances#

The PyMAPDL library contains the MapdlLocalPool class to simplify creating multiple local instances of Mapdl for batch processing. This can be used for the batch processing of a set of input files, convergence analysis, or other batch related processes.

To create the pool:

>>> from ansys.mapdl.core import LocalMapdlPool
>>> pool = LocalMapdlPool(10)
'MAPDL Pool with 10 active instances'

You can also supply additional keyword arguments when creating the pool. For instance, create several instances with 1 CPU each running at the current directory within their own isolated directories.

>>> import os
>>> my_path = os.getcmd()
>>> pool = LocalMapdlPool(10, nproc=1, run_location=my_path)
Creating Pool: 100%|########| 10/10 [00:01<00:00,  1.43it/s]

Each individual instance of mapdl can be accessed with:

>>> pool[0]
<ansys.mapdl.core.mapdl.MapdlGrpc object at 0x7f66270cc8d0>

Note that this is a self healing pool. If an instance of MAPDL dies during a batch process, that instance will be automatically restarted. You can disable this behavior by setting restart_failed=False when creating the pool.

Run a Set of Input Files#

You can use the pool to run a set of pre-generated input files using run_batch. For example, you can run the first set of 20 verification files with:

>>> from ansys.mapdl.core import examples
>>> files = [examples.vmfiles['vm%d' % i] for i in range(1, 21)]
>>> outputs = pool.run_batch(files)
>>> len(outputs)

Run a User Function#

You can also use the pool to run a custom user function to run on each instance of MAPDL over a set of inputs. This example again uses set of verification files as in the run_batch example, but implements it as a function and outputs the final routine instead of the text output from MAPDL.

>>> completed_indices = []
>>> def func(mapdl, input_file, index):
        # input_file, index = args
        output = mapdl.input(input_file)
        return mapdl.parameters.routine
>>> inputs = [(examples.vmfiles['vm%d' % i], i) for i in range(1, 10)]
>>> output =, inputs, progress_bar=True, wait=True)
['Begin level',
 'Begin level',
 'Begin level',
 'Begin level',
 'Begin level',
 'Begin level',
 'Begin level',
 'Begin level',
 'Begin level']

API Description#

For a full description of the PyMAPDL Pool API see Local MAPDL Pool.