problem with python numpy

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Johann Thurn
Johann Thurn am 31 Okt. 2018
I have started to try to use python functionality in matlab. The Textwrapper example works. I now tried other packages, and everytime there is some dependency on numpy I get this message:
problem in numpy - ImportError:
Importing the multiarray numpy extension module failed. Most
likely you are trying to import a failed build of numpy.
If you're working with a numpy git repo, try `git clean -xdf` (removes all
files not under version control). Otherwise reinstall numpy.
Original error was: DLL load failed: Das angegebene Modul wurde nicht gefunden.
If I try to use numpy directly, I get this:
>> x = py.numpy.random.random([4,4]);
Undefined variable "py" or class "py.numpy.random.random".
in Python works fine. Calling'textwrap')
in Matlab works,'numpy')
does not.
I have tried to update numpy and to remove and reinstall it, but this does nothing. I am using Python 3.6 which should be supported.
>> pyversion
version: '3.6'
executable: 'C:\ProgramData\Anaconda3\python.exe'
library: 'C:\ProgramData\Anaconda3\python36.dll'
home: 'C:\ProgramData\Anaconda3'
isloaded: 1
Maybe I am doing something wrong?

Akzeptierte Antwort

David Garrison
David Garrison am 27 Aug. 2020
Beginning in MATLAB R2018b, Python functions that accept numpy arrays may also accept MATLAB arrays without explicit conversion. When necessary, a numpy array can be created explicitly from a MATLAB array. For example, if you have a supported version of Python that is installed with the numpy library, you can do the following:
>> x = rand(2,2); % MATLAB array
>> y = py.numpy.array(x); % numpy array
y =
Python ndarray:
0.5943 0.8064
0.6133 0.1372
Use details function to view the properties of the Python object.
Use double function to convert to a MATLAB array.
Also beginning in MATLAB R2018b, it is possible to convert numeric numpy arrays returned from Python into MATLAB arrays. For example:
>> y = py.numpy.random.random([int32(2), int32(2)]) % numpy array
y =
Python ndarray:
0.5943 0.8064
0.6133 0.1372
Use details function to view the properties of the Python object.
Use double function to convert to a MATLAB array.
>> x = 2*double(y) % MATLAB array
x =
1.1885 1.6129
1.2266 0.2744
See the MATLAB documentation on Passing Matrices and Multidimensional Arrays for additional Information.

Weitere Antworten (4)

Prashanth Ramesh
Prashanth Ramesh am 5 Nov. 2018
Please note that MATLAB does not support Anaconda Python. To call Python libraries from MATLAB, you need to install a supported version of the reference implementation (CPython) for Python. MATLAB supports versions 2.7, 3.5, and 3.6. You can download CPython from
However possible workarounds for using Anaconda Python are listed below (though not officially supported):
1. Launch MATLAB from a properly configured Anaconda prompt. Then import numpy.
2. In Anaconda installation directory, copy the files %env_root%/libraries/bin/mkl_* to %env_root%/lib/site-packages/numpy/core.
  10 Kommentare
Lukas Brandl-Cheng
Lukas Brandl-Cheng am 17 Dez. 2022
2. worked for me too. As Paul Kuberry mentioned, the mkl files were in %env_root%/Library/bin/mkl_*. Additionally, I had to copy them to %env_root%/Lib/site-packages/numpy/core rather than %env_root%/lib/site-packages/numpy/core
Thanks for the solution!

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Igor Varfolomeev
Igor Varfolomeev am 9 Apr. 2020
Bearbeitet: Igor Varfolomeev am 9 Apr. 2020
I've noticed that simply adding the folder with the DLLs, related to numpy to PATH, just before starting Python also fixes the issue (R2019b update 5, Windows 10 version 1803).
For example, I create the environment with
conda create -n test_py36 python=3.6 numpy
and use setenv like this:
username = getenv('username');
setenv('PYTHONUNBUFFERED','1'); % doesn't change much, but just-in-case
setenv('path',['C:\Users\' username '\Anaconda3\envs\test_py36\Library\bin;', getenv('path')]);
pe=pyenv('Version',['C:\Users\' username '\Anaconda3\envs\test_py36\pythonw.exe'],...
...'ExecutionMode','OutOfProcess'... --- this (new mode) causes misc. issues
'ExecutionMode','InProcess'... --- this (old mode) works OK
(inspired by this)
  3 Kommentare
Flavio am 17 Apr. 2022
It worked very well.

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Vaibhav Arora
Vaibhav Arora am 6 Apr. 2019
Install Python (Cpython) from
Make sure the version you download is 64-bit if your Matlab exe is 64-bit. By default, a 32-bit cersion of python is downloaded so be careful.
Open python and try the command "import numpy as np". If you get an error, you need to install the library. For this, go to command prompt and type (for python 3): "pip3 install numpy"
Now you will be able to use numpy library in matlab
  1 Kommentar
Curious am 15 Jul. 2022
It isn't working. I have matlab R2018a and python 3.10. I have to use numpy in a matlab program. Kindly help

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I am not a robot
I am not a robot am 9 Sep. 2019
If you have setup an env(-ironment) in Anaconda, you need to setup the pyversion command to use the env.
Adapt the below to suit your needs
  3 Kommentare
Seth Wagenman
Seth Wagenman am 31 Aug. 2020
This works generally, Bram ter Huurne:
P.S. Where is the "general matlab-python website" where you suggest posting solutions, "as Anaconda is the general python distribution software for most users?"

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