CMake Error: The following variables are used in this project, but they are set to NOTFOUND. Please set them or make sure they are set and tested correctly in the CMake files: GOMP_LIBRARY

[kHarshit]

While using cmake PyTorch C++ Frontend Compilation for mask rcnn, I encountered the following error,

-- The C compiler identification is GNU 4.8.5
-- The CXX compiler identification is GNU 4.8.5
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Looking for include file pthread.h
-- Looking for include file pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE  
CMake Error at /nfs/interns/kharshit/libtorch/share/cmake/Caffe2/public/utils.cmake:17 (add_dependencies):
  add_dependencies Cannot add target-level dependencies to INTERFACE library
  target "torch_library".

Call Stack (most recent call first):
  /nfs/interns/kharshit/libtorch/share/cmake/Caffe2/Caffe2Config.cmake:121 (caffe2_interface_library)
  /nfs/interns/kharshit/libtorch/share/cmake/Torch/TorchConfig.cmake:40 (find_package)
  CMakeLists.txt:4 (find_package)


-- Found torch: /nfs/interns/kharshit/libtorch/lib/libtorch.so  
-- Found CUDA: /usr/local/cuda (found version "8.0") 
CMake Error: The following variables are used in this project, but they are set to NOTFOUND.
Please set them or make sure they are set and tested correctly in the CMake files:
GOMP_LIBRARY
    linked by target "mask-rcnn_demo" in directory /nfs/interns/kharshit/mlcpp/mask_rcnn_pytorch
    linked by target "mask-rcnn_train" in directory /nfs/interns/kharshit/mlcpp/mask_rcnn_pytorch

-- Configuring incomplete, errors occurred!
See also "/nfs/interns/kharshit/mlcpp/mask_rcnn_pytorch/build/CMakeFiles/CMakeOutput.log".
See also "/nfs/interns/kharshit/mlcpp/mask_rcnn_pytorch/build/CMakeFiles/CMakeError.log".

The error seems to be related to Eigen library, though I've already updated the submodules using git submodule update.

The procedure I followed to build is:

mkdir build
cd build
cmake -D CMAKE_PREFIX_PATH=~/libtorch/ ..

[Kolkir]

@kHarshit Hello, the error tells you that you don't have gomp library installed in yours system. This library is th OpenMP implementation for the C++ compiler you use.