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Out-of-Process Execution ofPythonFunctionality

Note

There is overhead associated with calling Python®functions out-of-process. This behavior affects performance. MathWorks recommends calling Python functions in-process, which is the default mode.

MATLAB®can run Python scripts and functions in a separate process. Running Python in a separate process enables you to:

  • Use some third-party libraries in the Python code that are not compatible with MATLAB.

  • 隔离MATLABprocess from crashes in the Python code.

To run out-of-process, call thepyenvfunction with the"ExecutionMode"argument set to"OutOfProcess". For example, suppose that you want to create thislistvariable in the Python environment.

['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday']

To create thislistout-of-process, set the MATLAB execution mode to"OutOfProcess". MATLAB displays information about your current Python environment.

pyenv("ExecutionMode","OutOfProcess")
ans = PythonEnvironment with properties: Version: "2.7" Executable: "C:\Python27\pythonw.exe" Library: "C:\windows\system32\python27.dll" Home: "C:\Python27" Status: NotLoaded ExecutionMode: OutOfProcess

Create the variable.

py.list({'Monday','Tuesday','Wednesday','Thursday','Friday'})
ans = Python list with no properties. ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday']

MATLAB创建一个命名的过程MATLABPyHost.

pyenv
ans = PythonEnvironment with properties: Version: "2.7" Executable: "C:\Python27\pythonw.exe" Library: "C:\windows\system32\python27.dll" Home: "C:\Python27" Status: Loaded ExecutionMode: OutOfProcess ProcessID: "8196" ProcessName: "MATLABPyHost"

Note

Clearing a Python object is asynchronous, which means that the Python object might remain in Python after the invocation of a synchronous call. For example, in the following code it is possible thatmyList2is created beforemyListis destroyed.

myList=py.list; clearmyListmyList2 = py.list;

Limitations

The size of variables passed between Python and MATLAB is limited to 2 GB when you call a Python function out-of-process. This limit applies to the data plus supporting information passed between the processes.

See Also

MATLAB Documentation

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