AI Glossary Term

What does “LoRA (Low-Rank Adaptation)” mean?

Definition

A parameter-efficient fine-tuning method that adds low-rank adapter matrices.

How LoRA (Low-Rank Adaptation) works

Diagram for LoRA (Low-Rank Adaptation), layers from top to bottom: Frozen pre-trained weights, unchanged; Small trainable adapter matrices, only these learn; Combined at run time: adapted model.Frozen pre-trained weights, unchangedSmall trainable adapter matrices, onlythese learnCombined at run time: adapted model

Example

Instead of updating all billions of weights in a language model, a team trains small adapter matrices for a customer-service style. The adapter file is small, and the same base model can swap different adapters for different clients.

Why it matters

LoRA makes fine-tuning possible on modest hardware and makes adapters easy to store and share.

Common questions

What does low-rank mean?

The weight changes are represented by two thin matrices multiplied together, which needs far fewer numbers than a full update.

Does LoRA match full fine-tuning?

Often close on many tasks, though full fine-tuning may do better on some.

Can adapters be combined?

Sometimes, with care. They can be merged into the base weights or swapped depending on the task.

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