1.6 KiB
1.6 KiB
LogSoftMax
@sphinxdirective
Versioned name: LogSoftmax-5
Category: Activation function
Short description: LogSoftmax computes the natural logarithm of softmax values for the given input.
.. note::
This is recommended to not compute LogSoftmax directly as Log(Softmax(x, axis)), more numeric stable is to compute LogSoftmax as:
.. math::
t = (x - ReduceMax(x,\ axis)) \ LogSoftmax(x, axis) = t - Log(ReduceSum(Exp(t),\ axis))
Attributes
-
axis
- Description: axis represents the axis of which the LogSoftmax is calculated. Negative value means counting dimensions from the back.
- Range of values: any integer value
- Type: int
- Default value: 1
- Required: no
Inputs:
- 1: Input tensor x of type T with enough number of dimension to be compatible with axis attribute. Required.
Outputs:
- 1: The resulting tensor of the same shape and of type T.
Types
- T: any floating-point type.
Mathematical Formulation
.. math::
y_{c} = ln\left(\frac{e^{Z_{c}}}{\sum_{d=1}^{C}e^{Z_{d}}}\right)
where :math:C is a size of tensor along axis dimension.
Example
.. code-block:: cpp
<layer ... type="LogSoftmax" ... > 256 56 256 56
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