Cannot install nlopt python module

user_13855884 0
Viewed 402

I am trying to install nlopt onto macOS 10.15.5. I downloaded the nlopt-2.6.2.tar.gz file from the NLopt docs and ran the following from the nlopt-2.6.2 directory:

mkdir build
cd build
cmake -DNLOPT_OCTAVE=Off -DNLOPT_MATLAB=Off -DNLOPT_GUILE=Off ..
make
sudo make install

I got the following output: cmake.txt.

The header file (nlopt.h) installs correctly to /usr/local/include and the dynamic library (libnlopt.dylib) installs correctly to /usr/local/lib/, but neither the dist-info file nor the nlopt module itself installs.

I have also tried installing via pip, brew, and conda, none of which have worked. I have also tried cloning from this Github, which didn't work either.

I appreciate any help with this, because I am completely lost. I am relatively new to this kind of stuff, and I couldn't find any good answers online.

nlopt macos python
1 Answers

The official docs are somewhat laconic about the exact steps required for building nlopt with Python bindings. First of all, you'll need SWIG installed:

$ brew install swig

Then, you'll need numpy to be available for the target Python interpreter. It is already preinstalled for the system Python, otherwise install it via Homebrew or pip, depending on your Python installation.

Now run cmake:

$ cmake -DNLOPT_GUILE=OFF -DNLOPT_MATLAB=OFF -DNLOPT_OCTAVE=OFF -DNLOPT_TESTS=OFF

This will build bindings against the default Python 2.7 installation preinstalled on MacOS. If you need to build against custom Python installation (e.g. when you've installed Python 3 via Homebrew or PKG installer from https://www.python.org/downloads), pass it via the PYTHON_EXECUTABLE arg:

$ cmake -DNLOPT_GUILE=OFF -DNLOPT_MATLAB=OFF -DNLOPT_OCTAVE=OFF -DNLOPT_TESTS=OFF -DPYTHON_EXECUTABLE=/usr/local/bin/python3

Inspect the log now - Python, SWIG and numpy headers should be successfully located. Example output snippet (you may have different paths/versions printed):

-- Found PythonInterp: /usr/local/bin/python3.8 (found version "3.8.3")
-- Found PythonLibs: /Library/Frameworks/Python.framework/Versions/3.8/lib/libpython3.8.dylib (found suitable exact version "3.8.3")
-- Found NumPy: /Users/hoefling/Library/Python/3.8/lib/python/site-packages/numpy/core/include (found version "1.19")
-- Found SWIG: /usr/local/bin/swig (found version "4.0.2")

If any of those conditions is not satisfied (e.g. you see Could NOT find NumPy, Could NOT find PythonLibs or Could NOT find SWIG), then stop and make sure the configuration succeeds before proceeding next.

Now compile:

$ make
...
Scanning dependencies of target nlopt_python_swig_compilation
[ 96%] Swig compile nlopt.i for python
[ 96%] Built target nlopt_python_swig_compilation
Scanning dependencies of target nlopt_python
[ 98%] Building CXX object src/swig/CMakeFiles/nlopt_python.dir/CMakeFiles/nlopt_python.dir/nloptPYTHON_wrap.cxx.o
[100%] Linking CXX shared module _nlopt.so
[100%] Built target nlopt_python

Install:

$ make install
...
-- Installing: /usr/local/lib/python3.8/site-packages/nlopt.py
-- Installing: /usr/local/lib/python3.8/site-packages/_nlopt.so

Test the Python bindings are importable:

$ python -c "import nlopt; print(nlopt.__version__)"
2.6.2
user_26502490
Related