Neural Network Field Guide

42 architectures and training schemes, from the perceptron (1958) to diffusion LLMs (2025).

Each diagram draws a network in miniature, from input at the bottom to output at the top. In most panels, a circle is one neuron; in sequence models, where each column is a token, it is that token's whole vector at one layer. A square is larger: an image patch, an expert network, a matrix-valued state. A cell's color and mark both show its role, so the diagrams read with or without color. Faded cells and links take little or no part in the step shown. Links show which tokens can read which. Wherever a part repeats, across positions, windows, copies, or passes, it uses the same weights. Each panel gives a year and the objective or learning rule of its original paper; many can be trained other ways. Select a diagram for its explanation, key, and papers.

How to read the diagrams

Input

  • Input
  • Image patch
  • Noisy input
  • Random noise
  • Visible unit (in and out)
  • Masked token

Hidden

  • Hidden
  • Probabilistic hidden
  • Capsule (vector output)
  • Expert (a whole network)
  • Router

State

  • Recurrent
  • Memory cell
  • Gated recurrent
  • Selective state (SSM)
  • Matrix-valued state

Mixing

  • Attention
  • Convolution or pooling

Output

  • Output
  • Reconstruction of input
  • Velocity

Links

  • Connection
  • Skip connection
  • Data passed on or fed back
  • Gate, acting at the dot
  • Cross-attention, comparison
  • Learnable function

Feed-forward and convolutional

Energy-based and self-organizing

Autoencoders and generative

Similarity

Flows and autoregressive models

Recurrent and memory

Attention

Linear-time sequence models

Routing and graphs

Key

Reading the diagram

Objective

Papers