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Pretrained model

As explained in Grokking AI Applications

A pretrained model is a model whose parameters have already been learned from an initial training corpus before later application or specialization.

A pretrained model has parameters learned during an initial training stage before those parameters are applied to new prompts during inference. Training starts with random parameters, then repeatedly adjusts them to reduce prediction errors. section 1.6

Its lifecycle has two practical stages:

  • Training learns parameters from many examples, such as human-readable text covering varied subjects and contexts. section 1.6
  • Inference applies the learned parameters to a prompt to generate a completion, rather than relearning the model each time. section 1.6
Figure 1.13 Enhancing a pretrained model through fine-tuning

Use the fine-tuning diagram to see how an already trained model can be enhanced for a later specialized use. section 1.6

How Grokking AI Applications covers it

How deep it goes
Explains parameter adjustment, backpropagation, training data, and inference, but stops short of detailed neural-network mathematics.
Examples
Uses GPT, GPT-3, sentence completion, a Rome prediction, and a 45-terabyte text dataset as concrete examples.
What it assumes
Assumes basic familiarity with prompts and completions while introducing neural-network training from random parameters.
What you can do after
Evaluate/understand how learned parameters support inference and why later specialization can begin from an existing model.
How it connects
Connects model training with inference, neural networks, parameters, backpropagation, and fine-tuning.

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