PReLU module — nn_prelu • torch

Applies the element-wise function: $$ \mbox{PReLU}(x) = \max(0,x) + a * \min(0,x) $$ or $$ \mbox{PReLU}(x) = \left\{ \begin{array}{ll} x, & \mbox{ if } x \geq 0 \\ ax, & \mbox{ otherwise } \end{array} \right. $$

Usage

nn_prelu(num_parameters = 1, init = 0.25)

Arguments

num_parameters: (int): number of $a$ to learn. Although it takes an int as input, there is only two values are legitimate: 1, or the number of channels at input. Default: 1
init: (float): the initial value of $a$. Default: 0.25

Details

Here $a$ is a learnable parameter. When called without arguments, nn.prelu() uses a single parameter $a$ across all input channels. If called with nn_prelu(nChannels), a separate $a$ is used for each input channel.

Note

weight decay should not be used when learning $a$ for good performance.

Channel dim is the 2nd dim of input. When input has dims < 2, then there is no channel dim and the number of channels = 1.

Shape

Input: $(N, *)$ where * means, any number of additional dimensions
Output: $(N, *)$, same shape as the input

Attributes

weight (Tensor): the learnable weights of shape (num_parameters).

Examples

if (torch_is_installed()) {
m <- nn_prelu()
input <- torch_randn(2)
output <- m(input)
}