Error loading MPI DLL in mpi4py

Question

I am trying to use Mpi4py 1.3 with python 2.7 on Windows 7 64bits. I downloaded the installable version from here which includes OpenMPI 1.6.3 so in the installed directory

Answer 1

I had the same issue and no answer solved the issue.

For me, the following solved the problem. I compiled and installed the mpi4py manually as follows:

• Install MPI SDK 10 for Windows from https://duongtrungnghia.wordpress.com/2017/03/28/install-mpi4py-on-windows-10/
• Add C:\Program Files (x86)\Microsoft SDKs\MPI\Lib and C:\Program Files (x86)\Microsoft SDKs\MPI to your Windows environment variables (not sure if needed)
• You need Visual Studio Build Tools with MSVC 140 or pure Visual Studio. Not sure what version. In my case, the mpi4py setup.py used C:\Program Files (x86)\Microsoft Visual Studio 14.0\.... although I use VS2017 currently.
• Install Windows SDK/Kits and dev tools (https://developer.microsoft.com/en-us/windows/downloads/windows-10-sdk)
  • Open Developer Command Prompt (It is like a CMD with some extras)
  • Activate your venv by executing (venv/Scripts/activate) if you use Virtualenv
  • Create and change to a temp directory and do the following:
    • git clone https://github.com/mpi4py/mpi4py.git
    • cd mpi4py
    • python -m pip install Cython
    • python setup.py build
    • python setup.py install

My setting:

• Windows 10
• Python 3.7