liveBook · Manning

Max pooling

As explained in Sutskever's List

A downsampling operation that retains the largest activation within each local spatial window.

Max pooling downsamples a feature map by keeping the strongest activation in each local spatial window. In AlexNet, this reduces computation and makes representations more robust to small positional changes and input distortions. section 2.5.1

AlexNet

AlexNet uses 3 × 3 max-pooling windows with stride 2 after its initial convolutional downsampling, reducing spatial dimensions further. section 2.5.1

Figure 2.3 The AlexNet architecture (cropped in the original paper). The numbers indicate spatial dimensions and channel depth at each stage. The input image (224 × 224 × 3 RGB) passes through a series of convolutional and pooling layers that progressively reduce spatial resolution (224→55→27→13) while increasing channel depth. Early downsampling is driven by the first convolutional layer (11 × 11 filters with a stride of 4), followed by max pooling layers (3 × 3 windows with a stride of 2) that further reduce spatial dimensions. The stride determines how far a filter moves across the input at each step, controlling how densely the image is sampled and how quickly spatial resolution is reduced. Filter sizes (11, 5, 3) are depicted as cubes and define the local receptive field of each convolution. The two horizontal streams reflect the model’s original two-GPU training setup, where feature maps were split across devices (e.g., 48 + 48 = 96 channels). The fully connected layers (4096 neurons, implemented as 2048 + 2048 across GPUs) feed into a 1000-way output for ImageNet classification. Used with permission granted by the lead author (Alex Krizhevsky).
figure

Trace how pooling layers reduce spatial resolution through AlexNet’s architecture. section 2.5.1

How Sutskever's List covers it

How deep it goes
Defines local maximum selection and explains its computational and positional-robustness effects, without detailing pooling variants.
Examples
Uses AlexNet’s 3 × 3 windows, stride 2, and progressively reduced spatial dimensions as concrete examples.
What you can do after
Understand how max pooling preserves strong local activations while reducing spatial dimensions and computation.
How it connects
Connects max pooling to convolutional layers, feature maps, and spatial downsampling.

Also explained in

Compare how 10 books explain max pooling →

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Sutskever's List. The section links point to the parts of the book it draws on.