How to handle multi Matlab return values in Python

I'm using Matlab 2014b, and I want to call Matlab function from Python(2.7.6). Here is my Python script:

 import matlab.engine as meng
 import matlab as mat
 eng = meng.start_matlab()
 try:
     x,y = eng.Fun_Py(3,4)
     print x
     print y
     eng.quit()
 except: 
     print "error in python script"
     eng.quit()

and here is my Matlab script:

function [x,y]=Fun_Py(a,b) x=zeros(a,b); y=sum(x); end

When I ran the Python scipt, I got "error in python script".How can I solve this problem? Any help is appreciate.

Jason Shih

Answer 1

[Bo Li]

There are two things need to be done.

1. Add the folder where Fun_Py.m is located into MATLAB path from MATLAB command window:

http://www.mathworks.com/help/matlab/ref/addpath.html?searchHighlight=addpath

Or you can change the current folder in MATLAB to where Fun_Py.m is located, for example if it is located in c:\temp:

 eng.cd(r'C:\temp)

2. Set the number of output to 2 if 2 output is expected:

 x,y = eng.Fun_Py(3,4, nargout=2)

[Jason Shih]

I tried as you said, and that works. Thank you very much!

[Petru-Daniel Tudosiu]

@Bo Li I tried what you said and it says that the function did not expect that explicit variable. I am using Python 3.4 with Matlab R2016b. Can You please help me?

[Bo Li]

I need more details maybe sample code to understand "the function did not expect that explicit variable".

A simple MATLAB function that returns multiple output is gcd:

 >>> a,b,c=eng.gcd(8,10, nargout=3)
 >>> a,b,c
 (2L, -1L, 1L)