FSRS vs SM2: How Spaced Repetition Algorithms Work

A technical deep dive into the SM2 and FSRS algorithms that power spaced repetition in tools like Anki. Whether you're curious about how your flashcards are scheduled or exploring alternatives to SM2, this video breaks down how these algorithms work, how they compare, and why FSRS is generally considered superior.

00:00 Intro - Why is FSRS so complicated?
03:02 SM2 Algorithm
08:23 FSRS and Forgetting Curves
12:14 DSR and DHP models
16:17 FSRS equations
21:25 Scheduling Simulator
23:59 Optimization and training weights
26:00 Stochastic Shortest Path Algorithm for Optimizing Spaced Repetition Scheduling
https://borretti.me/article/implementing-fsrs-in-100-lines
https://borretti.me/article/implementing-sm2-in-rust
https://expertium.github.io/Algorithm.html
https://www.desmos.com/calculator/au54ecrpiz
https://open-spaced-repetition.github.io/anki_fsrs_visualizer/
https://dl.acm.org/doi/10.1145/3534678.3539081

Видео FSRS vs SM2: How Spaced Repetition Algorithms Work канала StackWild