$ cd /usr/local/cuda-10.2/lib64
$ sudo ln -s -T libcublas.so /usr/lib/x86_64-linux-gnu/libcublas_device.so
This can work in my side for CUDA_cublas_device_LIBRARY-NOTFOUND issue.
$ cd /usr/local/cuda-10.2/lib64
$ sudo ln -s -T libcublas.so /usr/lib/x86_64-linux-gnu/libcublas_device.so
This can work in my side for CUDA_cublas_device_LIBRARY-NOTFOUND issue.