I'm new to python and would like to install lightgbm on my macbook. I did a pip install lightgbm and it said installation successful. However when I try to import that into my notebook I get the following error message:
../anaconda/envs/python3/lib/python3.6/ctypes/__init__.py in __init__(self, name, mode, handle, use_errno, use_last_error)
342
343 if handle is None:
--> 344 self._handle = _dlopen(self._name, mode)
345 else:
346 self._handle = handle
OSError: dlopen(../anaconda/envs/python3/lib/python3.6/site-packages/lightgbm/lib_lightgbm.so, 6): Library not loaded: /usr/local/opt/gcc/lib/gcc/7/libgomp.1.dylib
Referenced from: ../anaconda/envs/python3/lib/python3.6/site-packages/lightgbm/lib_lightgbm.so
Reason: image not found
The documentation on lightgbm website gives a different installation guideline using brew install.... My question is whether I have to do a brew install? If that's the case why the pip installation shows successful installation then?
pip would only install lightgbm python files. The documentation states that lightgbm depends on OpenMP. So you need to install that as well. The problem you are facing is because python cannot find the required "dynamic link library" that comes with OpenMP.
brew install open-mpi and it should fix the problem.
Sidenote: As a quick test, I installed lightgbm the same way you did, and faced the same problem. But I located the libgopm.1.dylib in /usr/local/opt/gcc/lib/gcc/6. Symlinking it to the required path didn't prove to be successful.