title: Where does anaconda install cudatoolkit and cudnn?
body: <p>I'm accustomed to installing the Cuda toolkit and cudnn from the Nvidia source, but have just tried installing via conda with the following:</p>
  
  <pre><code>conda install cudatoolkit=10.0
  conda install -c anaconda cudnn
  </code></pre>
  
  <p>I'm now trying to compile <a href="https://github.com/facebookresearch/faiss/blob/master/INSTALL.md#step-1-compiling-the-c-faiss" rel="nofollow noreferrer">FAISS</a> with cuda support, which requires me to pass the path to the cuda installation when compiling. </p>
  
  <p>Does anyone know where Anaconda installs the cuda toolkit? I'd also like to find where anaconda installs cudnn, in case that becomes relevant in the future. Any help others can offer with this question would be hugely helpful!</p>
  
  <p>OS: Ubuntu 18.04</p>
  
  <p>First I tried searching for the cuda toolkit with:</p>
  
  <pre><code>nvcc --version
  </code></pre>
  
  <p>but this returned:</p>
  
  <pre><code>Cuda compilation tools, release 9.1, V9.1.85
  </code></pre>
  
  <p>version 9.1, not 10.0! So then I tried:</p>
  
  <pre><code>locate cuda | grep /cuda$
  </code></pre>
  
  <p>This returned several things:</p>
  
  <pre><code>(3.6) user$ locate cuda | grep /cuda$
  /home/dhlab/anaconda3/envs/3.6/include/boost/fiber/cuda
  /home/dhlab/anaconda3/envs/3.6/lib/python3.6/site-packages/cupy/cuda
  /home/dhlab/anaconda3/envs/3.6/lib/python3.6/site-packages/numba/cuda
  /home/dhlab/anaconda3/envs/pixplot/lib/python3.6/site-packages/numba/cuda
  /home/dhlab/anaconda3/envs/pixplot/lib/python3.6/site-packages/tensorflow_core/include/external/local_config_cuda/cuda
  /home/dhlab/anaconda3/envs/pixplot/lib/python3.6/site-packages/tensorflow_core/include/external/local_config_cuda/cuda/cuda
  /home/dhlab/anaconda3/envs/pixplot/lib/python3.6/site-packages/tensorflow_core/include/tensorflow/stream_executor/cuda
  /home/dhlab/anaconda3/envs/stylegan/lib/python3.6/site-packages/tensorflow_core/include/external/local_config_cuda/cuda
  /home/dhlab/anaconda3/envs/stylegan/lib/python3.6/site-packages/tensorflow_core/include/external/local_config_cuda/cuda/cuda
  /home/dhlab/anaconda3/envs/stylegan/lib/python3.6/site-packages/tensorflow_core/include/tensorflow/stream_executor/cuda
  /home/dhlab/anaconda3/lib/python3.7/site-packages/numba/cuda
  /home/dhlab/anaconda3/pkgs/boost-cpp-1.70.0-h8e57a91_2/include/boost/fiber/cuda
  /home/dhlab/anaconda3/pkgs/cupy-7.3.0-py36h273e724_0/lib/python3.6/site-packages/cupy/cuda
  /home/dhlab/anaconda3/pkgs/numba-0.45.1-py37h962f231_0/lib/python3.7/site-packages/numba/cuda
  /home/dhlab/anaconda3/pkgs/numba-0.49.0rc1-np1.11py3.6h04863e7_gdc1c08865_0/lib/python3.6/site-packages/numba/cuda
  /usr/include/thrust/system/cuda
  /usr/lib/cuda
  </code></pre>
  
  <p>I thought <code>/usr/lib/cuda</code> looked inviting, so I looked at its contents, but it's empty! Then I thought the <code>local_config_cuda</code> inside <code>tensorflow_core</code> might have a clue, so I looked in there, where I found a single header file that contained:</p>
  
  <pre><code>#define TF_CUDA_VERSION "10.0"
  #define TF_CUDA_LIB_VERSION "10.0"
  #define TF_CUDNN_VERSION "7"
  
  #define TF_CUDA_TOOLKIT_PATH "/usr/local/cuda"
  </code></pre>
  
  <p>That sounds like the version of the cuda toolkit I installed with conda, but /usr/local/cuda does not exist!</p>
  
  <p>I'm clearly missing something. If someone with more experience with Conda-installed Cuda could help me find the Cuda toolkit so I can tell FAISS where to find it, I'd be very grateful.</p>