title: How to change CUDA version
body: <p>I met this error when compiling a modified caffe version.</p>
  
  <p><code>OpenCV static library was compiled with CUDA 7.5 support. Please, use the same version or rebuild OpenCV with CUDA 8.0</code></p>
  
  <p>I have some old code may not compatible with CUDA8.0, so I want to change my cuda version for this error.</p>
  
  <p>I modified my ~/.bash_profile like this</p>
  
  <pre><code># export PYTHONPATH=$PYTHONPATH:/usr/local/cuda-8.0/lib64/
  # export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda-8.0/lib64
  export PYTHONPATH=$PYTHONPATH:/usr/local/cuda-7.5/targets/x86_64-linux/lib/
  export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda-7.5/targets/x86_64-linux/lib/
  </code></pre>
  
  <p>But it did't work. Still the same error. What should I do? Thanks.</p>