Automatically Share MATLAB Engine and Set Its Startup Folder on Ubuntu

The MATLAB Engine API can connect Python to an already-running MATLAB desktop session. Two small pieces of configuration make this workflow convenient:

1. MATLAB shares itself automatically when it starts.
2. The Ubuntu application launcher opens MATLAB in the project directory.

The important detail is that the MATLAB and Python sides use different functions:

MATLAB:  matlab.engine.shareEngine('matlab')
Python:  matlab.engine.connect_matlab('matlab')

shareEngine publishes the current MATLAB process. connect_matlab is a Python Engine API function that attaches a Python process to that published session. Calling the Python function from MATLAB startup is an error.

• The target workflow
• Automatically share MATLAB at startup
  • Do not call connect_matlab from MATLAB
  • Avoid sharing the same session twice
• Set the startup working directory in Ubuntu
• Connect from Python
• Summary

The target workflow

After configuration, the workflow looks like this:

Ubuntu application launcher
            |
            v
    MATLAB desktop session
            |
            | startup.m calls shareEngine
            v
     Shared Engine session: matlab
            ^
            |
 Python calls connect_matlab("matlab")

The Python process reuses the desktop MATLAB process. It does not start a second MATLAB instance with start_matlab().

Automatically share MATLAB at startup

MATLAB executes a file named startup.m during startup if it can find the file on its MATLAB path. A common per-user location on Ubuntu is:

~/Documents/MATLAB/startup.m

Create the file if it does not exist and add:

if ~matlab.engine.isEngineShared
    matlab.engine.shareEngine('matlab');
end

The isEngineShared check makes the command safe if startup logic is run more than once in the same MATLAB process. The name matlab is just a shared-session name; Python must use the same name when connecting.

Do not call connect_matlab from MATLAB

This is the wrong startup file content:

matlab.engine.connect_matlab('matlab')

connect_matlab belongs in Python, not MATLAB. Using it in startup.m causes an error such as:

Unable to resolve the name matlab.engine.connect_matlab.

The correct MATLAB-side function is shareEngine.

Avoid sharing the same session twice

If this command is entered twice:

matlab.engine.shareEngine('matlab')

the first invocation shares the session and the second invocation reports that the current MATLAB session is already shared. The isEngineShared guard avoids that error during normal startup.

Set the startup working directory in Ubuntu

The MATLAB desktop launcher is usually a per-user .desktop file under:

~/.local/share/applications/

Open the MATLAB launcher for editing. Its existing Exec entry may look like this:

Exec="/opt/MATLAB/R2020a/bin/matlab" -desktop
Path=/opt/MATLAB/R2020a

Use MATLAB’s -sd option to select the startup directory, and set the desktop entry’s Path to the same directory:

Exec="/opt/MATLAB/R2020a/bin/matlab" -desktop -sd /path/to/project
Path=/path/to/project

Replace both example paths with the actual MATLAB installation and project directory. The -sd option controls MATLAB’s startup folder. The Path entry sets the Linux process working directory, so keeping both values aligned avoids confusion when MATLAB is launched from the application menu.

For example, a complete per-user entry can contain:

[Desktop Entry]
Version=1.0
Type=Application
Name=MATLAB R2020a
Exec="/opt/MATLAB/R2020a/bin/matlab" -desktop -sd /path/to/project
TryExec=/opt/MATLAB/R2020a/bin/matlab
Path=/path/to/project
Terminal=false
Categories=Science;Math;Engineering;

After saving the file, launch MATLAB from the application menu and verify the folder in the Command Window:

pwd

The result should be the project directory.

Connect from Python

Activate the Python environment containing the MATLAB Engine API and connect to the shared desktop session:

import matlab.engine

eng = matlab.engine.connect_matlab("matlab")
print("MATLAB folder:", eng.pwd())

From a shell, a compact connectivity check is:

python -c "import matlab.engine; e=matlab.engine.connect_matlab('matlab'); print(e.eval('pwd')); del e"

If the connection fails, check that:

• MATLAB is still running.
• startup.m contains shareEngine, not connect_matlab.
• Python imports matlab.engine from the intended environment.
• Both sides use the exact same session name, such as matlab.
• MATLAB and Python run as the same operating-system user.

Summary

The configuration is small but the API boundary matters:

startup.m  -> matlab.engine.shareEngine('matlab')
Python     -> matlab.engine.connect_matlab('matlab')
launcher   -> -sd /path/to/project

With these settings, MATLAB starts in the desired project directory, shares its desktop session automatically, and can be reused by Python without paying the startup cost of another MATLAB process.

For the Python Engine installation and version compatibility details, see Connect MATLAB R2020a to Python on Ubuntu.