title: WARNING (theano.sandbox.cuda): CUDA is installed, but device gpu is not available (error: cuda unavailable)
body: <p>in Ubuntu MATE 16.04 I'm trying to run the deep-learning python examples here using the GPU:</p>
  
  <p><a href="http://deeplearning.net/software/theano/tutorial/using_gpu.html" rel="noreferrer">testing Theano with GPU</a></p>
  
  <p>I did run the example code, </p>
  
  <pre><code>THEANO_FLAGS=mode=FAST_RUN,device=gpu,floatX=float32 python check1.py
  </code></pre>
  
  <p>but it seems that it is used the CPU and not the GPU. Here is the last part of terminal output:</p>
  
  <pre><code>WARNING (theano.sandbox.cuda): CUDA is installed, but device gpu0 is not  available  (error: cuda unavailable)
  ...
  Used the cpu
  </code></pre>
  
  <p>I tried to run this code too:</p>
  
  <pre><code>THEANO_FLAGS=device=cuda0 python check1.py
  </code></pre>
  
  <p>but the output is:</p>
  
  <pre><code>ERROR (theano.sandbox.gpuarray): pygpu was configured but could not be imported
  Traceback (most recent call last):
    File "/usr/local/lib/python2.7/dist-packages/theano/sandbox/gpuarray/__init__.py", line 20, in &lt;module&gt;
      import pygpu
  ImportError: No module named pygpu
  ...
  used cpu
  </code></pre>
  
  <p>I installed the cuda toolkit from apt.
  Here there are (hopefully) useful data:</p>
  
  <pre><code>python --version
  Python 2.7.12
  
  g++ -v
  gcc version 5.4.0
  
  nvcc --version
  Cuda compilation tools, release 7.5, V7.5.17
  
  lspci
  NVIDIA Corporation GM107 [GeForce GTX 750 Ti] (rev a2)
  
  nvidia-smi
  
  +------------------------------------------------------+                       
  | NVIDIA-SMI 361.42     Driver Version: 361.42         |                       
  |-------------------------------+----------------------+----------------------+
  | GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
  | Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
  |===============================+======================+======================|
  |   0  GeForce GTX 750 Ti  Off  | 0000:01:00.0      On |                  N/A |
  | 29%   35C    P8     1W /  38W |    100MiB /  2044MiB |      0%      Default |
  +-------------------------------+----------------------+----------------------+
  
  +-----------------------------------------------------------------------------+
  | Processes:                                                       GPU Memory |
  |  GPU       PID  Type  Process name                               Usage      |
  |=============================================================================|
  |    0      2861    G   /usr/lib/xorg/Xorg                              90MiB |
  +-----------------------------------------------------------------------------+
  </code></pre>