# LoRA Injection Reading

This starter is annotated reading material and the source of truth for the lab preview. Running anything is optional; the reading goal is to explain the mechanism without hiding behind a framework call.

## Reading focus

Read LoRA as a small trainable delta on selected weight matrices.

## Annotated sketch

```text
## LoRA mental model

```text
output = x @ base_weight
adapter_delta = scale * (x @ A @ B)
output = output + adapter_delta
```

Read the adapter as a small learned correction to an existing layer.
```

## What to explain

- base_weight remains the pretrained matrix.
- A and B form a low-rank update.
- scale controls how strongly the adapter changes the layer.

## Common trap

- LoRA is not a new scheduler.
- LoRA is not the same mechanism as ControlNet.