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LogSoftmax

class torch.nn.LogSoftmax(dim=None) [source]

Applies the log⁡(Softmax(x))\log(\text{Softmax}(x)) function to an n-dimensional input Tensor.

The LogSoftmax formulation can be simplified as:

LogSoftmax(xi)=log⁡(exp⁡(xi)∑jexp⁡(xj))\text{LogSoftmax}(x_{i}) = \log\left(\frac{\exp(x_i) }{ \sum_j \exp(x_j)} \right)
Shape:
  • Input: (∗)(*) where * means, any number of additional dimensions
  • Output: (∗)(*), same shape as the input
Parameters

dim (int) – A dimension along which LogSoftmax will be computed.

Returns

a Tensor of the same dimension and shape as the input with values in the range [-inf, 0)

Return type

None

Examples:

>>> m = nn.LogSoftmax(dim=1)
>>> input = torch.randn(2, 3)
>>> output = m(input)
extra_repr() [source]

Return the extra representation of the module.

Return type

str

forward(input) [source]

Runs the forward pass.

Return type

Tensor

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https://docs.pytorch.org/docs/2.9/generated/torch.nn.LogSoftmax.html