This section provides a general overview of PyMAPDL and how you use it.
ansys-mapdl-core library creates an instance of the
Mapdl class in the background and sends
commands to that service. Errors and warnings are processed
Pythonically, letting you develop a script in real time, without
worrying about it functioning correctly when deployed in batch
MAPDL can be started from Python in gRPC mode using the
launch_mapdl() method. This starts
MAPDL in a temporary directory by default. You can change this to
your current directory with:
import os from ansys.mapdl.core import launch_mapdl path = os.getcwd() mapdl = launch_mapdl(run_location=path)
MAPDL is now active, and you can send commands to it as a genuine a Python class. For example, if you wanted to create a surface using key points, you could run:
mapdl.run("/PREP7") mapdl.run("K, 1, 0, 0, 0") mapdl.run("K, 2, 1, 0, 0") mapdl.run("K, 3, 1, 1, 0") mapdl.run("K, 4, 0, 1, 0") mapdl.run("L, 1, 2") mapdl.run("L, 2, 3") mapdl.run("L, 3, 4") mapdl.run("L, 4, 1") mapdl.run("AL, 1, 2, 3, 4")
MAPDL interactively returns the result of each command, which is stored to the logging module. Errors are caught immediately. For example, if you input an invalid command:
>>> mapdl.run("AL, 1, 2, 3") apdlRuntimeError: L, 1, 2, 3 EFINE AREA BY LIST OF LINES INE LIST = 1 2 3 TRAVERSED IN SAME DIRECTION AS LINE 1) ** ERROR *** CP = 0.338 TIME= 09:45:36 eypoint 1 is referenced by only one line. Improperly connected line et for AL command.
MapdlRuntimeError was caught immediately. This means that
you can write your MAPDL scripts in Python, run them interactively, and
then run them as a batch without worrying if the script would run correctly if
you had instead outputted it to a script file.
Mapdl class supports much more
than just sending text to MAPDL. It includes higher-level wrapping,
allowing for better scripting and interaction with MAPDL. For an overview of the
various advanced methods to visualize, script, and interact with MAPDL, see
Calling MAPDL Pythonically#
MAPDL functions can be called directly from an instance of
Mapdl in a Pythonic manner. This is
to simplify calling Ansys, especially when inputs are variables within
Python. For example, the following two commands are equivalent:
mapdl.k(1, 0, 0, 0) mapdl.run("K, 1, 0, 0, 0")
This approach has some obvious advantages. Chiefly, it’s easier
to script because
ansys-mapdl-core takes care of the string formatting for you.
For example, you can input points from a numpy array with:
# make 10 random keypoints in Ansys points = np.random.random((10, 3)) for i, (x, y, z) in enumerate(points): mapdl.k(i + 1, x, y, z)
Additionally, exceptions are caught and handled within Python.
>>> mapdl.run("AL, 1, 2, 3") xception: L, 1, 2, 3 EFINE AREA BY LIST OF LINES INE LIST = 1 2 3 TRAVERSED IN SAME DIRECTION AS LINE 1) ** ERROR *** CP = 0.338 TIME= 09:45:36 eypoint 1 is referenced by only one line. Improperly connected line et for AL command.
For longer scripts, instead of sending commands to MAPDL as in the area creation example, you can instead run:
# clear existing geometry mapdl.finish() mapdl.clear() # create a square area using keypoints mapdl.prep7() mapdl.k(1, 0, 0, 0) mapdl.k(2, 1, 0, 0) mapdl.k(3, 1, 1, 0) mapdl.k(4, 0, 1, 0) mapdl.l(1, 2) mapdl.l(2, 3) mapdl.l(3, 4) mapdl.l(4, 1) mapdl.al(1, 2, 3, 4)
This approach has some obvious advantages, chiefly that it’s a bit
easier to script as
takes care of the string formatting for you. For example, inputting
points from a numpy array:
import numpy as np # make 10 random keypoints in MAPDL points = np.random.random((10, 3)) for i, (x, y, z) in enumerate(points): mapdl.k(i + 1, x, y, z)
Additionally, each function with the MAPDL class has help associated with it. For example:
>>> help(mapdl.k) Help on method K in module ansys.mapdl.core.mapdl_grpc.MapdlGrpc: k(npt='', x='', y='', z='') method of ansys.mapdl.core.mapdl_grpc.MapdlGrpc instance Defines a keypoint. APDL Command: K Parameters ---------- npt Reference number for keypoint. If zero, the lowest available number is assigned [NUMSTR]. x, y, z Keypoint location in the active coordinate system (may be R, θ, Z or R, θ, Φ). If X = P, graphical picking is enabled and all other fields (including NPT) are ignored (valid only in the GUI). Examples -------- Create a keypoint at (1, 1, 2) >>> mapdl.k(1, 1, 1, 2) Notes ----- Defines a keypoint in the active coordinate system [CSYS] for line, area, and volume descriptions. A previously defined keypoint of the same number is then redefined. A keypoint may be redefined only if it is not yet attached to a line or is not yet meshed. Solid modeling in a toroidal system is not recommended.
For stability considerations, see PyMAPDL stability.