torch.bernoulli

torch.bernoulli(input, *, generator=None, out=None) → Tensor

Draws binary random numbers (0 or 1) from a Bernoulli distribution.

The input tensor should be a tensor containing probabilities to be used for drawing the binary random number. Hence, all values in input have to be in the range: \(0 \leq \text{input}_i \leq 1\).

The \(\text{i}^{th}\) element of the output tensor will draw a value \(1\) according to the \(\text{i}^{th}\) probability value given in input.

\[\text{out}_{i} \sim \mathrm{Bernoulli}(p = \text{input}_{i}) \]

The returned out tensor only has values 0 or 1 and is of the same shape as input.

out can have integral dtype, but input must have floating point dtype.

Parameters:

input (Tensor) – the input tensor of probability values for the Bernoulli distribution

Keyword Arguments:

• generator (torch.Generator, optional) – a pseudorandom 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.]])