Issue with CBC library in Python-MIP on macOS ARM64 (Apple Silicon)

[juanbellonrz]

Hi, I’m trying to run a Python script that uses the python-mip library with the CBC solver on a MacBook with an ARM64 (Apple Silicon) chip.

• I’ve installed CBC correctly using Homebrew (brew install cbc), and I can verify its availability by running cbc --version in the terminal.

• However, when I run my script in Spyder, I get the following error:

An error occurred while loading the CBC library: cannot load library 'cbc-c-darwin-x86-64.dylib'...
mach-o file, but is an incompatible architecture (have 'x86_64', need 'arm64')
....
NameError: name 'cbclib' is not defined

• I checked that my CBC installation is for ARM64 using:

file /opt/homebrew/lib/libcbc.dylib

Output: Mach-O 64-bit dynamically linked shared library arm64

• I have also added the following environment variables in my script before importing mip:
  import os
  import ctypes

os.environ["DYLD_LIBRARY_PATH"] = "/opt/homebrew/lib:/opt/anaconda3/lib"
os.environ["PATH"] = "/opt/homebrew/bin:" + os.environ.get("PATH", "")
ctypes.CDLL("/opt/homebrew/lib/libcbc.dylib")

from mip import Model, CBC
model = Model(solver_name=CBC)

Despite these efforts, the issue persists. The script runs fine from the terminal, but in Spyder, I still get the architecture mismatch error.

I would appreciate any suggestions on how to force python-mip to use the correct version of CBC installed via Homebrew or how to resolve this compatibility issue in Spyder.

Thanks in advance.