number generator for sampling
  * **out** (*Tensor**, **optional*) -- the output tensor.

Example:
  >>> a = torch.empty(3, 3).uniform_(0, 1)  # generate a uniform random matrix with range [0, 1]
  >>> a
  tensor([[ 0.1737,  0.0950,  0.3609],
          [ 0.7148,  0.0289,  0.2676],
          [ 0.9456,  0.8937,  0.7202]])
  >>> torch.bernoulli(a)
  tensor([[ 1.,  0.,  0.],
          [ 0.,  0.,  0.],
          [ 1.,  1.,  1.]])

  >>> a = torch.ones(3, 3) # probability of drawing "1" is 1
  >>> torch.bernoulli(a)
  tensor([[ 1.,  1.,  1.],
          [ 1.,  1.,  1.],
          [ 1.,  1.,  1.]])
  >>> a = torch.zeros(3, 3) # probability of drawing "1" is 0
  >>> torch.bernoulli(a)
  tensor([[ 0.,  0.,  0.],
          [ 0.,  0.,  0.],
          [ 0.,  0.,  0.]])
