title: Error libtorch_python.so: cannot open shared object file: No such file or directory
body: <p>I'm trying to implement fastai pretrain language model and it requires torch to work. After run the code, I got some problem about the import torch._C </p>
  
  <p>I run it on my linux, python 3.7.1, via pip: torch 1.0.1.post2, cuda V7.5.17. I'm getting this error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "pretrain_lm.py", line 7, in &lt;module&gt;
      import fastai
    File "/home/andira/anaconda3/lib/python3.7/site-packages/fastai/__init__.py", line 1, in &lt;module&gt;
      from .basic_train import *
    File "/home/andira/anaconda3/lib/python3.7/site-packages/fastai/basic_train.py", line 2, in &lt;module&gt;
      from .torch_core import *
    File "/home/andira/anaconda3/lib/python3.7/site-packages/fastai/torch_core.py", line 2, in &lt;module&gt;
      from .imports.torch import *
    File "/home/andira/anaconda3/lib/python3.7/site-packages/fastai/imports/__init__.py", line 2, in &lt;module&gt;
      from .torch import *
    File "/home/andira/anaconda3/lib/python3.7/site-packages/fastai/imports/torch.py", line 1, in &lt;module&gt;
      import torch, torch.nn.functional as F
    File "/home/andira/anaconda3/lib/python3.7/site-packages/torch/__init__.py", line 84, in &lt;module&gt;
      from torch._C import *
  ImportError: libtorch_python.so: cannot open shared object file: No such file or directory
  </code></pre>
  
  <p>So I tried to run this line:</p>
  
  <pre><code>from torch._C import *
  </code></pre>
  
  <p>and got same result</p>
  
  <pre><code>ImportError: libtorch_python.so: cannot open shared object file: No such file or directory
  </code></pre>
  
  <p>I checked <code>/home/andira/anaconda3/lib/python3.7/site-packages/torch/lib</code> and there are only <code>libcaffe2_gpu.so</code> and <code>libshm.so</code> file, and I can't find libtorch_python.so either. My question is, what is actually libtorch_python.so? I've read some of article and like most of it talked about <em>undefined symbol</em>, not <em>cannot open shared object file: No such file or directory</em> like mine. I'm new at python and torch so I really appreciate your answer.</p>