OptiSLang instance management

You use the Optislang class to launch optiSLang as a server and to control and query optiSLang projects. You can either launch optiSLang locally or connect to a remote optiSLang instance.

Note

When you are done using an optiSLang instance, you should always use the dispose() method to shut down the instance gracefully. If you use the Optislang class as a context manager, it executes the dispose() method automatically, even when an exception is raised.

Launch optiSLang locally

The Optislang class must know the location of the optiSLang executable file to run. By default, the latest installed version of optiSLang is launched. To initialize an optiSLang instance and start it locally as a server, run this code:

from ansys.optislang.core import Optislang

osl = Optislang()
print(osl)
osl.dispose()

Calling the dispose() method closes the connection with the optiSLang server. If an optiSLang instance is started with the shutdown_on_finished parameter set to True, which is the default, the server shuts down automatically. For information on how to keep the server running after disposing the optiSLang instance, see Optislang instance disposal and optional optiSLang server shutdown.

To get a list of all supported optiSLang executable files, run this code:

from ansys.optislang.core import utils

print(utils.find_all_osl_exec())

To launch a specific optiSLang version shown in the list of supported executable files, or to launch a supported version from a non-standard installation location, use the executable parameter to specify the path to the desired executable file:

from ansys.optislang.core import Optislang

osl = Optislang(
    executable=r"C:\\Program Files\\Dynardo\\Ansys optiSLang\\2023 R1\\optislang.com"
)
print(osl)
osl.dispose()

To open a specific project or create a project, use the project_path parameter. This code creates a project in the current working directory:

from ansys.optislang.core import Optislang
from pathlib import Path

path = Path.cwd()
project_name = "test.opf"

osl = Optislang(project_path=path / project_name)
print(osl)
osl.dispose()

Connect to a remote optiSLang instance

For remote connection, it is assumed that optiSLang is already running as a server on a remote (or local) host. To connect to this running instance, you must specify the host and port. Parameters related to the execution of a new optiSLang server are ignored.

This code initializes optiSLang and connects to a remote optiSLang server:

from ansys.optislang.core import Optislang

host = "127.0.0.1"  # specify host
port = 5310  # specify port

osl = Optislang(host=host, port=port)
print(osl)
osl.dispose()

Calling the dispose() method closes the connection with the remote optiSLang server. However, if this server was started with the shutdown_on_finished parameter set to False, the server won’t shut down. You must use the shutdown() method to shut down the server before disposing the Optislang instance. For more information, see Optislang instance disposal and optional optiSLang server shutdown.

Optislang instance disposal and optional optiSLang server shutdown

As mentioned earlier, when an Optislang instance is no longer in use, you should always use the dispose() method to shut down the instance gracefully.

Optionally, you can use the shutdown() method to shut down the OptiSLang server. However, you must call this method before the dispose() method and only if the server is not set to shutdown automatically when finished.

Differences in the termination methods mentioned earlier follow:

• The dispose() method only closes the connection with the optiSLang server.

• The shutdown() method sends a command to shut down the optiSLang server, which is necessary when termination of the server is requested and either of these situations exist:

  • The server is started locally by an optiSLang instance with the shutdown_on_finished parameter set to False.

  • The optiSLang instance is connected to a remote optiSLang server, that is not set to shutdown automatically when finished (--shutdown-on-finished post argument was not used).

To specify whether to automatically shut down the optiSLang server, you can use the shutdown_on_finished parameter in the Optislang instance constructor. The default value for this parameter is True. This means that the optiSLang server is shut down automatically after the dispose() method is called.

To keep a locally started optiSLang server running even after disposing the Optislang instance, you must set the shutdown_on_finished parameter to False when creating the instance. In this case, to shut down the optiSLang server, you must call the shutdown() method before disposing the Optislang instance.

The following examples show possible termination cases of the optiSLang instance initialized with the shutdown_on_finished parameter set to False.

• To keep the optiSLang server running, use only the dispose() method:

  from ansys.optislang.core import Optislang
  
  osl = Optislang(shutdown_on_finished=False)
  print(osl)
  osl.dispose()
  

• To shut down the optiSLang server, use both the

  shutdown() and dispose() methods:

  from ansys.optislang.core import Optislang
  
  osl = Optislang(shutdown_on_finished=False)
  print(osl)
  osl.shutdown()
  osl.dispose()
  

You can use the same approach when connected to a remote optiSLang server.

Initialization	shutdown_on_finished	Methods	optiSLang server is running
Local	True	dispose()	No
	False	dispose()	Yes
		shutdown() dispose()	No
Remote	True	dispose()	No
	False	dispose()	Yes
		shutdown() dispose()	No

Context manager

You should use the Optislang class as a context manager. The main advantage of this approach is that the optiSLang instance and connection to the optiSLang server automatically shut down gracefully, even if an error occurs when calling the dispose() method.

from ansys.optislang.core import Optislang

with Optislang() as osl:
    print(osl)
    osl.application.project.start()

Note

When an optiSLang instance is started with the shutdown_on_finished parameter set to False, or if the instance is connected to an optiSLang server started with this setting, the default behavior is to close the connection and keep the optiSLang server running. To stop the optiSLang server, you must use the shutdown() method.

from ansys.optislang.core import Optislang

with Optislang(shutdown_on_finished=False) as osl:
    print(osl)
    osl.start()
    osl.shutdown()