Setting and retrieving parameters

MAPDL parameters can be retrieved from an instance of Mapdl using the Mapdl.parameters. For example, if you want to use MAPDL’s Mapdl.get() method to populate a parameter, you can then access the parameter with code:

>>> from ansys.mapdl.core import launch_mapdl
>>> mapdl = launch_mapdl()
>>> mapdl.get("DEF_Y", "NODE", 2, "U", "Y")
>>> mapdl.parameters["DEF_Y"]

You can also set both scalar and array parameters from Python objects using Mapdl.parameters with:

>>> mapdl.parameters["MY_ARRAY"] = np.arange(10000)
>>> mapdl.parameters["MY_ARRAY"]
array([0.00000e+00, 1.00000e+00, 2.00000e+00, ..., 9.99997e+05,
       9.99998e+05, 9.99999e+05])

>>> mapdl.parameters["MY_STRING"] = "helloworld"
>>> mapdl.parameters["MY_STRING"]
"helloworld"

You can also access some built-in parameters normally accessed through the Mapdl.get() method. For example, instead of getting the current routine with \*GET, ACTIVE, 0, ROUT, you can access it with this code:

>>> mapdl.parameters.routine
'Begin level'

For a full list of the methods and attributes available to the Parameters class, see Parameters.

For additional information on PyMAPDL array limitations, see Issues when importing and exporting numpy arrays in MAPDL.

Specially named parameters

Parameters with leading underscores

Parameters starting with an underscore ('_') are reserved parameters for MAPDL macros and routines. Their use is discouraged, and in PyMAPDL you cannot set them directly.

If you need to set one of these parameters, you can use the Mapdl._run attribute to avoid PyMAPDL parameter name checks:

>>> mapdl._run("_parameter=123")
'PARAMETER _PARAMETER =     123.00000000'

By default, this type of parameter cannot be seen when issuing the Mapdl.parameters attribute. However, you can change this by setting the Mapdl.parameters.show_leading_underscore_parameters to True:

>>> mapdl.parameters.show_leading_underscore_parameters = True
>>> mapdl.parameters
MAPDL Parameters
----------------
PORT                             : 50053.0
_RETURN                          : 0.0
_STATUS                          : 0.0
_UIQR                            : 17.0

Parameters with trailing underscores

Parameters ending with an underscore are recommended for user routines and macros. You can set this type of parameter in PyMAPDL, but by default, they cannot be seen in the Mapdl.parameters attribute unless the Mapdl.parameters.show_trailing_underscore_parameters attribute is set to True:

>>> mapdl.parameters["param_"] = 1.0
>>> mapdl.parameters
MAPDL Parameters
----------------
>>> mapdl.parameters.show_trailing_underscore_parameters = True
>>> mapdl.parameters
MAPDL Parameters
----------------
PARAM_                           : 1.0

Parameters with leading and trailing underscores

Parameters with both leading and trailing underscores are a special type. These parameters CANNOT be seen in the Mapdl.parameters attribute under any circumstances. Their use is not recommended.

You can still retrieve these special parameters using any of the normal methods for retrieving parameters. However, you must know the parameter name:

>>> mapdl.parameters["_param_"] = 1.0
>>> mapdl.parameters
MAPDL Parameters
----------------
>>> print(mapdl.parameters["_param_"])
1.0