nn_lp_pool2d function

Applies a 2D power-average pooling over an input signal composed of several input planes.

Applies a 2D power-average pooling over an input signal composed of several input planes.

On each window, the function computed is:

nn_lp_pool2d(norm_type, kernel_size, stride = NULL, ceil_mode = FALSE)

Arguments

  • norm_type: if inf than one gets max pooling if 0 you get sum pooling ( proportional to the avg pooling)
  • kernel_size: the size of the window
  • stride: the stride of the window. Default value is kernel_size
  • ceil_mode: when TRUE, will use ceil instead of floor to compute the output shape

Details

f(X)=xXxpp f(X) = \sqrt[p]{\sum_{x \in X} x^{p}}
  • At p = \infty, one gets Max Pooling
  • At p = 1, one gets Sum Pooling (which is proportional to average pooling)

The parameters kernel_size, stride can either be:

  • a single int -- in which case the same value is used for the height and width dimension
  • a tuple of two ints -- in which case, the first int is used for the height dimension, and the second int for the width dimension

Note

If the sum to the power of p is zero, the gradient of this function is not defined. This implementation will set the gradient to zero in this case.

Shape

  • Input: (N,C,Hin,Win)(N, C, H_{in}, W_{in})
  • Output: (N,C,Hout,Wout)(N, C, H_{out}, W_{out}), where
Hout=Hin\mboxkernel_size[0]\mboxstride[0]+1 H_{out} = \left\lfloor\frac{H_{in} - \mbox{kernel\_size}[0]}{\mbox{stride}[0]} + 1\right\rfloor Wout=Win\mboxkernel_size[1]\mboxstride[1]+1 W_{out} = \left\lfloor\frac{W_{in} - \mbox{kernel\_size}[1]}{\mbox{stride}[1]} + 1\right\rfloor

Examples

if (torch_is_installed()) { # power-2 pool of square window of size=3, stride=2 m <- nn_lp_pool2d(2, 3, stride = 2) # pool of non-square window of power 1.2 m <- nn_lp_pool2d(1.2, c(3, 2), stride = c(2, 1)) input <- torch_randn(20, 16, 50, 32) output <- m(input) }
  • Maintainer: Daniel Falbel
  • License: MIT + file LICENSE
  • Last published: 2025-02-14