Issues in using matlab in python

Hello everyone ,

I am trying to solve an optimization problem where the input to the function to be optimized is a 12x1 vector and the output is a matrix of size 6x3.

I tried solving this using fsolve, root solvers from scipy.optimize

but got the following error:

fsolve: there is a mismatch between the input and output shape of the 'func' argument 'f'.Shape should be (12,) but it is (6,3).

but this problem can be easily solved in matlab using fsolve.

So i created a very simplified version of the original problem :

import matlab.engine

eng = matlab.engine.start_matlab()

import numpy as np

func = lambda x: x[0]**2 + x[1]**2 -25

eng.fsolve(func,eng.rand(2,1))



Traceback (most recent call last):

File "<stdin>", line 1, in <module>

File "C:\Users\reach\anaconda3\envs\MyEnv\lib\site-packages\matlab\engine\matlabengine.py", line 66, in __call__

out=_stdout, err=_stderr)

TypeError: unsupported Python data type: function

Any suggestion would be of great help.

Thank you.

Answer 1

[Abhijeet]

Hi Ajai,

I can understand that you are facing issue while using ‘MATLAB Engine API for Python’. The error you're encountering is due to the fact that you're passing a Python lambda function (func) to the eng.fsolve function, which expects a MATLAB function handle.

I would suggest to code ‘func’ function in MATLAB script and then use that script in python script.

For more information on using MATLAB script in python, refer to the following documentation: -https://www.mathworks.com/help/matlab/matlab_external/call-user-script-and-function-from-python.html