AI Grimoire
Tree — 03
sft/1peft/4

Fine-tuning

Adapting a pretrained model without paying to pretrain it. Mostly a study in which parameters you are allowed to leave frozen, and what the frozen ones cost you in precision.

Five entries across two branches. One is a stub and is marked as such — read them as open questions rather than answers.

Supervised fine-tuning

sft/ ›

the baseline every other method is measured against

03.1
Supervised Fine-Tuningstandard
Cross-entropy on completion tokens only; the step that makes a base model answer.
O(n·d²)

Parameter-efficient methods

peft/ ›

low-rank updates and the arithmetic of merging them

03.2
Adapter Mergingstubcommon
Task arithmetic, TIES and DARE over independently trained deltas.
O(d)
03.3
DoRAcommon
Low-rank adaptation split into a magnitude and a direction.
O(r·d)
03.4
LoRAstandard
Low-rank additive update to frozen weight matrices during adaptation.
O(r·d)
03.5
QLoRAstandard
4-bit NF4 base weights with paged optimiser state and LoRA adapters.
O(r·d)