What is the reason for this error and how can I fix it? I am running the code from this repo: GitHub - facebookresearch/frankmocap: A Strong and Easy-to-use Single View 3D Hand+Body Pose Estimator 1
(frank) mona@goku:~/research/code/frankmocap$ python -m demo.demo_frankmocap --input_path ./sample_data/han_short.mp4 --out_dir ./mocap_output
Traceback (most recent call last):
  File "/usr/lib/python3.8/runpy.py", line 194, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib/python3.8/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/home/mona/research/code/frankmocap/demo/demo_frankmocap.py", line 25, in <module>
    from handmocap.hand_bbox_detector import HandBboxDetector
  File "/home/mona/research/code/frankmocap/handmocap/hand_bbox_detector.py", line 33, in <module>
    from detectors.hand_object_detector.lib.model.roi_layers import nms # might raise segmentation fault at the end of program
  File "/home/mona/research/code/frankmocap/detectors/hand_object_detector/lib/model/roi_layers/__init__.py", line 3, in <module>
    from .nms import nms
  File "/home/mona/research/code/frankmocap/detectors/hand_object_detector/lib/model/roi_layers/nms.py", line 3, in <module>
    from model import _C
ImportError: /home/mona/research/code/frankmocap/detectors/hand_object_detector/lib/model/_C.cpython-38-x86_64-linux-gnu.so: undefined symbol: _ZN6caffe28TypeMeta21_typeMetaDataInstanceIdEEPKNS_6detail12TypeMetaDataEv

I have:
$ lsb_release -a
LSB Version:	core-11.1.0ubuntu2-noarch:security-11.1.0ubuntu2-noarch
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.2 LTS
Release:	20.04
Codename:	focal

and
$ python
Python 3.8.5 (default, Jan 27 2021, 15:41:15) 
[GCC 9.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import torch
>>> torch.__version__
'1.8.1+cu111'
>>> import detectron2
>>> detectron2.__version__
'0.4'
>>> from detectron2 import _C

and:
$ python -m detectron2.utils.collect_env
----------------------  --------------------------------------------------------------------------
sys.platform            linux
Python                  3.8.5 (default, Jan 27 2021, 15:41:15) [GCC 9.3.0]
numpy                   1.19.5
detectron2              0.4 @/home/mona/venv/frank/lib/python3.8/site-packages/detectron2
Compiler                GCC 7.3
CUDA compiler           CUDA 11.1
detectron2 arch flags   3.7, 5.0, 5.2, 6.0, 6.1, 7.0, 7.5, 8.0, 8.6
DETECTRON2_ENV_MODULE   <not set>
PyTorch                 1.8.1+cu111 @/home/mona/venv/frank/lib/python3.8/site-packages/torch
PyTorch debug build     False
GPU available           True
GPU 0                   GeForce GTX 1650 Ti with Max-Q Design (arch=7.5)
CUDA_HOME               /usr
Pillow                  8.1.0
torchvision             0.9.1+cu111 @/home/mona/venv/frank/lib/python3.8/site-packages/torchvision
torchvision arch flags  3.5, 5.0, 6.0, 7.0, 7.5, 8.0, 8.6
fvcore                  0.1.3.post20210311
cv2                     4.5.1
----------------------  --------------------------------------------------------------------------
PyTorch built with:
  - GCC 7.3
  - C++ Version: 201402
  - Intel(R) Math Kernel Library Version 2020.0.0 Product Build 20191122 for Intel(R) 64 architecture applications
  - Intel(R) MKL-DNN v1.7.0 (Git Hash 7aed236906b1f7a05c0917e5257a1af05e9ff683)
  - OpenMP 201511 (a.k.a. OpenMP 4.5)
  - NNPACK is enabled
  - CPU capability usage: AVX2
  - CUDA Runtime 11.1
  - NVCC architecture flags: -gencode;arch=compute_37,code=sm_37;-gencode;arch=compute_50,code=sm_50;-gencode;arch=compute_60,code=sm_60;-gencode;arch=compute_70,code=sm_70;-gencode;arch=compute_75,code=sm_75;-gencode;arch=compute_80,code=sm_80;-gencode;arch=compute_86,code=sm_86
  - CuDNN 8.0.5
  - Magma 2.5.2
  - Build settings: BLAS_INFO=mkl, BUILD_TYPE=Release, CUDA_VERSION=11.1, CUDNN_VERSION=8.0.5, CXX_COMPILER=/opt/rh/devtoolset-7/root/usr/bin/c++, CXX_FLAGS= -Wno-deprecated -fvisibility-inlines-hidden -DUSE_PTHREADPOOL -fopenmp -DNDEBUG -DUSE_KINETO -DUSE_FBGEMM -DUSE_QNNPACK -DUSE_PYTORCH_QNNPACK -DUSE_XNNPACK -O2 -fPIC -Wno-narrowing -Wall -Wextra -Werror=return-type -Wno-missing-field-initializers -Wno-type-limits -Wno-array-bounds -Wno-unknown-pragmas -Wno-sign-compare -Wno-unused-parameter -Wno-unused-variable -Wno-unused-function -Wno-unused-result -Wno-unused-local-typedefs -Wno-strict-overflow -Wno-strict-aliasing -Wno-error=deprecated-declarations -Wno-stringop-overflow -Wno-psabi -Wno-error=pedantic -Wno-error=redundant-decls -Wno-error=old-style-cast -fdiagnostics-color=always -faligned-new -Wno-unused-but-set-variable -Wno-maybe-uninitialized -fno-math-errno -fno-trapping-math -Werror=format -Wno-stringop-overflow, LAPACK_INFO=mkl, PERF_WITH_AVX=1, PERF_WITH_AVX2=1, PERF_WITH_AVX512=1, TORCH_VERSION=1.8.1, USE_CUDA=ON, USE_CUDNN=ON, USE_EXCEPTION_PTR=1, USE_GFLAGS=OFF, USE_GLOG=OFF, USE_MKL=ON, USE_MKLDNN=ON, USE_MPI=OFF, USE_NCCL=ON, USE_NNPACK=ON, USE_OPENMP=ON, 



uninstalled and installed detectron2 and same ImportError: /home/mona/research/code/frankmocap/detectors/hand_object_detector/lib/model/_C.cpython-38-x86_64-linux-gnu.so: undefined symbol: _ZN6caffe28TypeMeta21_typeMetaDataInstanceIdEEPKNS_6detail12TypeMetaDataEv · Issue #96 · facebookresearch/frankmocap · GitHub 6