Matlab Engine for Python

This repo gives examples of calling Matlab functions from Python using Matlab Engine for Python.

Install necessary packages for these examples:

conda install --file requirements.txt

# OR
python -m pip install -r requirements.txt

Python can directly exchange data with Matlab and call Matlab functions via Matlab Engine for Python. Setup Matlab Engine for Python:

python -m pip install matlabengine

Or install directly from Matlab directory like:

python -m pip install $(matlab -batch "disp(matlabroot)" | tail -n1)/extern/engines/python/

Article explains more details of Matlab Engine for Python.

Numpy.ndarray return from Matlab

Matlab Engine accepts Numpy.ndarray into Matlab functions. Getting Numpy.ndarray from Matlab Engine returned arrays requires like:

import numpy
import matlab.engine
eng = matlab.engine.start_matlab("-nojvm")

x = numpy.random.random((3,2))

y_m = eng.my_matlab_fun(x)

y = numpy.array(y_m.tomemoryview()).reshape(y_m.size, order="F")

Matlab functions with more than one output

For Matlab functions that return more than one output, use "nargout=" like:

import matlab.engine
eng = matlab.engine.start_matlab("-nojvm")

x, y = eng.myfun(x, nargout=2)

HDF5 data exchange

To avoid using Matlab Engine, which requires compatible versions of Python and Matlab, one can interchange data using a file and calling the other language interpreter.

Example: image_hdf5.py calls Matlab function image_hdf5.m.

Matlab Engine example: image_matlab_engine.py.

Matlab using Python

Matlab can use Python code via pyenv.

Example: image_proc.m.

Troubleshooting

Numpy import issues

check_numpy.m shows how to check issues with DLLs on Windows with Numpy and Matlab.

Python importlib can also give hints about problems importing:

py.importlib.import_module('numpy')

Other things to try especially on Windows include:

setenv("KMP_DUPLICATE_LIB_OK", "TRUE")

this avoids Matlab crash below--is this error from Matlab libiomp5md.dll loaded and Numpy also loads that DLL?

OMP: Error #15: Initializing libiomp5md.dll, but found libiomp5md.dll already initialized.