Why does Anaconda install pytorch cpuonly when I install cuda?
I have created a Python 3.7 conda virtual environment and installed the following packages using this command:
conda install pytorch torchvision torchaudio cudatoolkit=11.3 matplotlib scipy opencv -c pytorch
They install fine, but then when I come to run my program I get the following error which suggests that a CUDA enabled device is not found:
    raise RuntimeError('Attempting to deserialize object on a CUDA '
RuntimeError: Attempting to deserialize object on a CUDA device but torch.cuda.is_available() is False. If you are running on a CPU-only machine, please use torch.load with map_location=torch.device('cpu') to map your storages to the CPU.

I have an NVIDIA RTX 3060ti GPU, which as far as I am aware is cuda enabled, but whenever I go into the Python interactive shell within my conda environment I get False when evaluating torch.cuda.is_available() suggesting that perhaps CUDA is not installed properly or is not found.
When I then perform a conda list to view my installed packages:
# packages in environment at /home/user/anaconda3/envs/FGVC:
#
# Name                    Version                   Build  Channel
_libgcc_mutex             0.1                        main  
_openmp_mutex             4.5                       1_gnu  
blas                      1.0                         mkl  
brotli                    1.0.9                he6710b0_2  
bzip2                     1.0.8                h7b6447c_0  
ca-certificates           2021.10.26           h06a4308_2  
cairo                     1.16.0               hf32fb01_1  
certifi                   2021.10.8        py37h06a4308_2  
cpuonly                   1.0                           0    pytorch
cudatoolkit               11.3.1               h2bc3f7f_2  
cycler                    0.11.0             pyhd3eb1b0_0  
dbus                      1.13.18              hb2f20db_0  
expat                     2.4.4                h295c915_0  
ffmpeg                    4.0                  hcdf2ecd_0  
fontconfig                2.13.1               h6c09931_0  
fonttools                 4.25.0             pyhd3eb1b0_0  
freeglut                  3.0.0                hf484d3e_5  
freetype                  2.11.0               h70c0345_0  
giflib                    5.2.1                h7b6447c_0  
glib                      2.69.1               h4ff587b_1  
graphite2                 1.3.14               h23475e2_0  
gst-plugins-base          1.14.0               h8213a91_2  
gstreamer                 1.14.0               h28cd5cc_2  
harfbuzz                  1.8.8                hffaf4a1_0  
hdf5                      1.10.2               hba1933b_1  
icu                       58.2                 he6710b0_3  
imageio                   2.16.0                   pypi_0    pypi
imageio-ffmpeg            0.4.5                    pypi_0    pypi
imutils                   0.5.4                    pypi_0    pypi
intel-openmp              2021.4.0          h06a4308_3561  
jasper                    2.0.14               hd8c5072_2  
jpeg                      9d                   h7f8727e_0  
kiwisolver                1.3.2            py37h295c915_0  
lcms2                     2.12                 h3be6417_0  
ld_impl_linux-64          2.35.1               h7274673_9  
libffi                    3.3                  he6710b0_2  
libgcc-ng                 9.3.0               h5101ec6_17  
libgfortran-ng            7.5.0               ha8ba4b0_17  
libgfortran4              7.5.0               ha8ba4b0_17  
libglu                    9.0.0                hf484d3e_1  
libgomp                   9.3.0               h5101ec6_17  
libopencv                 3.4.2                hb342d67_1  
libopus                   1.3.1                h7b6447c_0  
libpng                    1.6.37               hbc83047_0  
libstdcxx-ng              9.3.0               hd4cf53a_17  
libtiff                   4.2.0                h85742a9_0  
libuuid                   1.0.3                h7f8727e_2  
libuv                     1.40.0               h7b6447c_0  
libvpx                    1.7.0                h439df22_0  
libwebp                   1.2.0                h89dd481_0  
libwebp-base              1.2.0                h27cfd23_0  
libxcb                    1.14                 h7b6447c_0  
libxml2                   2.9.12               h03d6c58_0  
lz4-c                     1.9.3                h295c915_1  
matplotlib                3.5.0            py37h06a4308_0  
matplotlib-base           3.5.0            py37h3ed280b_0  
mkl                       2021.4.0           h06a4308_640  
mkl-service               2.4.0            py37h7f8727e_0  
mkl_fft                   1.3.1            py37hd3c417c_0  
mkl_random                1.2.2            py37h51133e4_0  
munkres                   1.1.4                      py_0  
ncurses                   6.3                  h7f8727e_2  
networkx                  2.6.3                    pypi_0    pypi
ninja                     1.10.2           py37hd09550d_3  
numpy                     1.21.2           py37h20f2e39_0  
numpy-base                1.21.2           py37h79a1101_0  
olefile                   0.46                     py37_0  
opencv                    3.4.2            py37h6fd60c2_1  
openssl                   1.1.1m               h7f8727e_0  
packaging                 21.3               pyhd3eb1b0_0  
pcre                      8.45                 h295c915_0  
pillow                    8.4.0            py37h5aabda8_0  
pip                       21.2.2           py37h06a4308_0  
pixman                    0.40.0               h7f8727e_1  
py-opencv                 3.4.2            py37hb342d67_1  
pyparsing                 3.0.4              pyhd3eb1b0_0  
pyqt                      5.9.2            py37h05f1152_2  
python                    3.7.11               h12debd9_0  
python-dateutil           2.8.2              pyhd3eb1b0_0  
pytorch                   1.7.0               py3.7_cpu_0  [cpuonly]  pytorch
pywavelets                1.2.0                    pypi_0    pypi
qt                        5.9.7                h5867ecd_1  
readline                  8.1.2                h7f8727e_1  
scikit-image              0.19.1                   pypi_0    pypi
scipy                     1.7.3            py37hc147768_0  
setuptools                58.0.4           py37h06a4308_0  
sip                       4.19.8           py37hf484d3e_0  
six                       1.16.0             pyhd3eb1b0_1  
sqlite                    3.37.2               hc218d9a_0  
tifffile                  2021.11.2                pypi_0    pypi
tk                        8.6.11               h1ccaba5_0  
torchaudio                0.7.0                      py37    pytorch
torchvision               0.8.1                  py37_cpu  [cpuonly]  pytorch
tornado                   6.1              py37h27cfd23_0  
typing_extensions         3.10.0.2           pyh06a4308_0  
wheel                     0.37.1             pyhd3eb1b0_0  
xz                        5.2.5                h7b6447c_0  
zlib                      1.2.11               h7f8727e_4  
zstd                      1.4.9                haebb681_0  

There seems to be a lot of things saying cpuonly, but I am not sure how they came about, since I did not install them.
I am running Ubuntu version 20.04.4 LTS

I believe I had the following things wrong that prevented me from using Cuda. Despite having cuda installed the nvcc --version command indicated that Cuda was not installed and so what I did was add it to the path using this answer.
Despite doing that and deleting my original conda environment and using the conda install pytorch torchvision torchaudio cudatoolkit=11.3 matplotlib scipy opencv -c pytorch command again I still got False when evaluating torch.cuda.is_available().
I then used this command conda install pytorch torchvision torchaudio cudatoolkit=10.2 matplotlib scipy opencv -c pytorch changing cudatoolkit from verison 11.3 to version 10.2 and then it worked!
Now torch.cuda.is_available() evaluates to True
Unfortunately, Cuda version 10.2 was incompatible with my RTX 3060 gpu (and I'm assuming it is not compatible with all RTX 3000 cards). Cuda version 11.0 was giving me errors and Cuda version 11.3 only installs the CPU only versions for some reason. Cuda version 11.1 worked perfectly though!
This is the command I used to get it to work in the end:
pip install torch==1.9.0+cu111 torchvision==0.10.0+cu111 torchaudio==0.9.0 -f https://download.pytorch.org/whl/torch_stable.html
