Install xgboost on Mac - ld: library not found

问题:

I am trying to install OpenMP enabled xgboost on my mac. I installed gcc with no problem:

brew install gcc --without-multilib

then cloned git repository:

git clone --recursive https://github.com/dmlc/xgboost
cd xgboost; cp make/config.mk ./config.mk

but I get an error when I do

make -j4

Here is the error I get. I'd appreciate if you can help fixing this problem:

c++ -std=c++0x -Wall -O3 -msse2  -Wno-unknown-pragmas -funroll-loops -Iinclude   -Idmlc-core/include -Irabit/include -fPIC -fopenmp -o xgboost  build/cli_main.o build/learner.o build/logging.o build/c_api/c_api.o build/c_api/c_api_error.o build/common/common.o build/data/data.o build/data/simple_csr_source.o build/data/simple_dmatrix.o build/data/sparse_page_dmatrix.o build/data/sparse_page_raw_format.o build/data/sparse_page_source.o build/data/sparse_page_writer.o build/gbm/gblinear.o build/gbm/gbm.o build/gbm/gbtree.o build/metric/elementwise_metric.o build/metric/metric.o build/metric/multiclass_metric.o build/metric/rank_metric.o build/objective/multiclass_obj.o build/objective/objective.o build/objective/rank_obj.o build/objective/regression_obj.o build/tree/tree_model.o build/tree/tree_updater.o build/tree/updater_colmaker.o build/tree/updater_histmaker.o build/tree/updater_prune.o build/tree/updater_refresh.o build/tree/updater_skmaker.o build/tree/updater_sync.o dmlc-core/libdmlc.a rabit/lib/librabit.a  -pthread -lm  -fopenmp 
c++ -std=c++0x -Wall -O3 -msse2  -Wno-unknown-pragmas -funroll-loops -Iinclude   -Idmlc-core/include -Irabit/include -fPIC -fopenmp -shared -o lib/libxgboost.so build/learner.o build/logging.o build/c_api/c_api.o build/c_api/c_api_error.o build/common/common.o build/data/data.o build/data/simple_csr_source.o build/data/simple_dmatrix.o build/data/sparse_page_dmatrix.o build/data/sparse_page_raw_format.o build/data/sparse_page_source.o build/data/sparse_page_writer.o build/gbm/gblinear.o build/gbm/gbm.o build/gbm/gbtree.o build/metric/elementwise_metric.o build/metric/metric.o build/metric/multiclass_metric.o build/metric/rank_metric.o build/objective/multiclass_obj.o build/objective/objective.o build/objective/rank_obj.o build/objective/regression_obj.o build/tree/tree_model.o build/tree/tree_updater.o build/tree/updater_colmaker.o build/tree/updater_histmaker.o build/tree/updater_prune.o build/tree/updater_refresh.o build/tree/updater_skmaker.o build/tree/updater_sync.o dmlc-core/libdmlc.a rabit/lib/librabit.a -pthread -lm  -fopenmp 
clangclang: : warningwarning: : argument unused during compilation: '-pthread'argument unused during compilation: '-pthread'

ld: library not found for -lgomp
ld: library not found for -lgomp
clang: error: clanglinker command failed with exit code 1 (use -v to see invocation): 
error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [lib/libxgboost.so] Error 1
make: *** Waiting for unfinished jobs....
make: *** [xgboost] Error 1

回答1:

I have the same issue and solved it by:

brew install clang-omp
export CC=clang-omp
export CXX=clang-omp++
git clone --recursive https://github.com/dmlc/xgboost
cd xgboost; cp make/config.mk ./config.mk; make -j4
cd python-package
sudo python setup.py install

If you used pip to install xgboost before, then delete the previous installed xgboost from your project. Then use

pip install xgboost 

to install it again.

回答2:

A new versions of OSX has a Clang as a default c\c++ compiler. Therefore your c++ command refers to clang++.

You should define a CC\CXX environmental variables for your make command like this CC=gcc CXX=g++ make -j

Also you can build an OpenMP for clang OpenMPrt and customise your shell environment (I didn't try this by own)

(I have no mac at this moment to check this solution; just linux)