# Opencv 4.6.0 with cuda support were successfully built for both python2.7 and python3.8, but cuda unavailable **URL:** \ **Category:** Jetson Xavier NX\ **Tags:** opencv, pytorch, cudnn, cuda\ **Created:** [November 1, 2023, 5:20am UTC](https://forums.developer.nvidia.com/t/opencv-4-6-0-with-cuda-support-were-successfully-built-for-both-python2-7-and-python3-8-but-cuda-unavailable/271391 "2023-11-01T05:20:17Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![iris980125](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@iris980125](https://forums.developer.nvidia.com/u/iris980125)\ **Post date:** [November 1, 2023, 5:20am UTC](https://forums.developer.nvidia.com/t/opencv-4-6-0-with-cuda-support-were-successfully-built-for-both-python2-7-and-python3-8-but-cuda-unavailable/271391/1 "2023-11-01T05:20:17Z")
Hi I am struggling with activating CUDA (maybe version of pytorch, opencv and python?.) I am using Jetson Xavier NX developer kit, installed _ **Jetpack 5.0.2** _ so _ **CUDA 11.4 ver and cuDNN 8.4 ver** _ came together. To use GPU support I deleted default _ **opencv** _ (4.5.4) of Jetpack and rebuilt _ **4.6.0** _ by modifying Cmake -D attribute of JetsonHack([GitHub - jetsonhacks/nano\_build\_opencv: Build OpenCV on Nvidia Jetson Nano](https://github.com/jetsonhacks/nano_build_opencv). Here comes problem - `import cv2` in both python version were available, but `cv2.cuda.getCudaEnabledDeviceCount()` return 0 and `torch.cuda.is_available()` return False. I downloaded wheel file in this page ([PyTorch for Jetson - #1367 by 19565337738](https://forums.developer.nvidia.com/t/pytorch-for-jetson/72048/1367)) and followed installation guide. And also I checked proper CUDA version for _ **pytorch 1.11.0** _ is CUDA 11.4 by torch.version.cuda in python script - so I can be assure version is not cause of my problem. When I check cv2.getBuildInformation(), **python (for build) is printed like this : /usr/bin/python2.7** [attachment for more information - in python3.8] ```auto >>> print(cv2.getBuildInformation()) General configuration for OpenCV 4.6.0 ===================================== Version control: unknown Extra modules: Location (extra): /home/seo/opencv_contrib-4.6.0/modules Version control (extra): unknown Platform: Timestamp: 2023-11-01T00:25:15Z Host: Linux 5.10.104-tegra aarch64 CMake: 3.16.3 CMake generator: Unix Makefiles CMake build tool: /usr/bin/make Configuration: RELEASE CPU/HW features: Baseline: NEON FP16 C/C++: Built as dynamic libs?: YES C++ standard: 11 C++ Compiler: /usr/bin/c++ (ver 9.4.0) C++ flags (Release): -fsigned-char -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -O3 -DNDEBUG -DNDEBUG C++ flags (Debug): -fsigned-char -W -Wall -Wreturn-type -Wnon-virtual-dtor -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wundef -Winit-self -Wpointer-arith -Wshadow -Wsign-promo -Wuninitialized -Wsuggest-override -Wno-delete-non-virtual-dtor -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -fvisibility-inlines-hidden -g -O0 -DDEBUG -D_DEBUG C Compiler: /usr/bin/cc C flags (Release): -fsigned-char -W -Wall -Wreturn-type -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -O3 -DNDEBUG -DNDEBUG C flags (Debug): -fsigned-char -W -Wall -Wreturn-type -Waddress -Wsequence-point -Wformat -Wformat-security -Wmissing-declarations -Wmissing-prototypes -Wstrict-prototypes -Wundef -Winit-self -Wpointer-arith -Wshadow -Wuninitialized -Wno-comment -Wimplicit-fallthrough=3 -Wno-strict-overflow -fdiagnostics-show-option -pthread -fomit-frame-pointer -ffunction-sections -fdata-sections -fvisibility=hidden -g -O0 -DDEBUG -D_DEBUG Linker flags (Release): -Wl,--gc-sections -Wl,--as-needed -Wl,--no-undefined Linker flags (Debug): -Wl,--gc-sections -Wl,--as-needed -Wl,--no-undefined ccache: NO Precompiled headers: NO Extra dependencies: m pthread cudart_static -lpthread dl rt nppc nppial nppicc nppidei nppif nppig nppim nppist nppisu nppitc npps cublas cudnn cufft -L/usr/local/cuda-11.4/lib64 -L/usr/lib/aarch64-linux-gnu 3rdparty dependencies: OpenCV modules: To be built: alphamat aruco barcode bgsegm bioinspired calib3d ccalib core cudaarithm cudabgsegm cudacodec cudafeatures2d cudafilters cudaimgproc cudalegacy cudaobjdetect cudaoptflow cudastereo cudawarping cudev cvv datasets dnn dnn_objdetect dnn_superres dpm face features2d flann freetype fuzzy gapi hdf hfs highgui img_hash imgcodecs imgproc intensity_transform line_descriptor mcc ml objdetect optflow phase_unwrapping photo plot python2 python3 quality rapid reg rgbd saliency sfm shape stereo stitching structured_light superres surface_matching text tracking video videoio videostab viz wechat_qrcode xfeatures2d ximgproc xobjdetect xphoto Disabled: world Disabled by dependency: - Unavailable: java julia matlab ovis ts Applications: apps Documentation: NO Non-free algorithms: YES GUI: QT5 QT: YES (ver 5.12.8 ) QT OpenGL support: YES (Qt5::OpenGL 5.12.8) OpenGL support: YES (/usr/lib/aarch64-linux-gnu/libGL.so /usr/lib/aarch64-linux-gnu/libGLU.so) VTK support: YES (ver 6.3.0) Media I/O: ZLib: /usr/lib/aarch64-linux-gnu/libz.so (ver 1.2.11) JPEG: /usr/lib/aarch64-linux-gnu/libjpeg.so (ver 80) WEBP: /usr/lib/aarch64-linux-gnu/libwebp.so (ver encoder: 0x020e) PNG: /usr/lib/aarch64-linux-gnu/libpng.so (ver 1.6.37) TIFF: /usr/lib/aarch64-linux-gnu/libtiff.so (ver 42 / 4.1.0) JPEG 2000: OpenJPEG (ver 2.3.1) OpenEXR: /usr/lib/aarch64-linux-gnu/libImath.so /usr/lib/aarch64-linux-gnu/libIlmImf.so /usr/lib/aarch64-linux-gnu/libIex.so /usr/lib/aarch64-linux-gnu/libHalf.so /usr/lib/aarch64-linux-gnu/libIlmThread.so (ver 2_3) HDR: YES SUNRASTER: YES PXM: YES PFM: YES Video I/O: FFMPEG: YES avcodec: YES (58.54.100) avformat: YES (58.29.100) avutil: YES (56.31.100) swscale: YES (5.5.100) avresample: YES (4.0.0) GStreamer: YES (1.16.3) v4l/v4l2: YES (linux/videodev2.h) Xine: YES (ver 1.2.9) Parallel framework: pthreads Trace: YES (with Intel ITT) Other third-party libraries: Lapack: YES (/usr/lib/aarch64-linux-gnu/liblapack.so /usr/lib/aarch64-linux-gnu/libcblas.so /usr/lib/aarch64-linux-gnu/libatlas.so) Eigen: YES (ver 3.3.7) Custom HAL: YES (carotene (ver 0.0.1)) Protobuf: build (3.19.1) NVIDIA CUDA: YES (ver 11.4, CUFFT CUBLAS FAST_MATH) NVIDIA GPU arch: 72 NVIDIA PTX archs: cuDNN: YES (ver 8.4.1) OpenCL: YES (no extra features) Include path: /home/seo/opencv-4.6.0/3rdparty/include/opencl/1.2 Link libraries: Dynamic load Python 2: Interpreter: /usr/bin/python2.7 (ver 2.7.18) Libraries: /usr/lib/aarch64-linux-gnu/libpython2.7.so (ver 2.7.18) numpy: /usr/lib/python2.7/dist-packages/numpy/core/include (ver 1.16.5) install path: lib/python2.7/dist-packages/cv2/python-2.7 Python 3: Interpreter: /usr/bin/python3.8 (ver 3.8.10) Libraries: /usr/lib/aarch64-linux-gnu/libpython3.8.so (ver 3.8.10) numpy: /home/seo/.local/lib/python3.8/site-packages/numpy/core/include (ver 1.24.4) install path: /home/seo/.pyenv/versions/3.8.10/lib/python3.8/site-packages/cv2/python-3.8 Python (for build): /usr/bin/python2.7 Java: ant: NO JNI: NO Java wrappers: NO Java tests: NO Install to: /usr/local ----------------------------------------------------------------- >>> cv2.cuda.getCudaEnabledDeviceCount() 0 >>> torch.cuda.is_available() False >>> exit() ``` I think this is the main reason because when I try to `import torch` in python 2.7, it returns > ‘no module named torch’ but same action works in python3.8… but still, `cv2.cuda.getCudaEnabledDeviceCount()` returns 0. Can anybody answer my question? Is REALLY version of python used for building openCV cause this problem? How can I end this issue? I am struggling with this problem for about 2 weeks so would be very appriciate with your help In addition, I changed default python version of bash shell to 3.8 but it didn’t change anything, failed to build opencv with python 3.8 . Do you know how to force this? IF this is not the main reason, **installed CUDA itself** has problem? This is output of `nvcc --version` ```auto nvcc: NVIDIA (R) Cuda compiler driver Copyright (c) 2005-2022 NVIDIA Corporation Built on Wed_May__4_00:02:26_PDT_2022 Cuda compilation tools, release 11.4, V11.4.239 Build cuda_11.4.r11.4/compiler.31294910_0 ``` ---
**Author:** ![AastaLLL](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/aastalll/32/14043_2.png) [@AastaLLL](https://forums.developer.nvidia.com/u/AastaLLL)\ **Post date:** [November 1, 2023, 8:48am UTC](https://forums.developer.nvidia.com/t/opencv-4-6-0-with-cuda-support-were-successfully-built-for-both-python2-7-and-python3-8-but-cuda-unavailable/271391/3 "2023-11-01T08:48:11Z")
Hi, Do you run the test within a container? If yes, please add `--system-site-packages` to access the host package. Or you can check our container below which has both OpenCV and PyTorch installed. > **[NVIDIA L4T ML | NVIDIA NGC](https://catalog.ngc.nvidia.com/orgs/nvidia/containers/l4t-ml)** > > Get started on your AI journey quickly on Jetson. The Machine learning container contains TensorFlow, PyTorch, JupyterLab, and other popular ML and data science frameworks such as scikit-learn, scipy, and Pandas pre-installed in a Python 3.6... Thanks. ---
**Author:** ![iris980125](https://developer.download.nvidia.com/images/forums/profile-default-devtalk-84.png) [@iris980125](https://forums.developer.nvidia.com/u/iris980125)\ **Post date:** [November 2, 2023, 12:32am UTC](https://forums.developer.nvidia.com/t/opencv-4-6-0-with-cuda-support-were-successfully-built-for-both-python2-7-and-python3-8-but-cuda-unavailable/271391/4 "2023-11-02T00:32:51Z")
@AastaLLL No, I’m not familiar with L4T so I didn’t tried container yet Is it better than creating virtual environment by conda? ---
**Author:** ![AastaLLL](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/aastalll/32/14043_2.png) [@AastaLLL](https://forums.developer.nvidia.com/u/AastaLLL)\ **Post date:** [November 2, 2023, 4:20am UTC](https://forums.developer.nvidia.com/t/opencv-4-6-0-with-cuda-support-were-successfully-built-for-both-python2-7-and-python3-8-but-cuda-unavailable/271391/5 "2023-11-02T04:20:32Z")
Hi, No, just in case you are facing the error due to the virtual environment setting. For OpenCV, could you try the below script instead? [https://github.com/AastaNV/JEP/blob/master/script/install\_opencv4.6.0\_Jetson.sh](https://github.com/AastaNV/JEP/blob/master/script/install_opencv4.6.0_Jetson.sh) For PyTorch, we now only provide the package for Python3. Please try it with Python3 instead. Thanks. ---
**Author:** ![system](https://sea2.discourse-cdn.com/nvidia/user_avatar/forums.developer.nvidia.com/system/32/68080_2.png) [@system](https://forums.developer.nvidia.com/u/system)\ **Post date:** [November 21, 2023, 5:29am UTC](https://forums.developer.nvidia.com/t/opencv-4-6-0-with-cuda-support-were-successfully-built-for-both-python2-7-and-python3-8-but-cuda-unavailable/271391/7 "2023-11-21T05:29:12Z")
Closed on November 21, 2023, 5:29am UTC This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.