✨ A modern Anki custom scheduling based on Free Spaced Repetition Scheduler algorithm ✨
FSRS4Anki consists of two main parts: scheduler and optimizer.
The scheduler is based on a variant of the DSR (Difficulty, Stability, Retrievability) model, which is used to predict memory states. The scheduler aims to achieve the requested retention for each card and each review.
The optimizer applies Maximum Likelihood Estimation and Backpropagation Through Time to estimate the stability of memory and learn the laws of memory from time-series review logs. Then, it can find the optimal retention to minimize the repetitions via the stochastic shortest path algorithm.
For more detail on the mechanism of the FSRS algorithm, please see my papers: A Stochastic Shortest Path Algorithm for Optimizing Spaced Repetition Scheduling and Optimizing Spaced Repetition Schedule by Capturing the Dynamics of Memory.
FSRS4Anki Helper is an Anki add-on that supports the FSRS4Anki Scheduler. It has six features:
- Reschedule cards based on their entire review histories.
- Postpone due cards whose retention is higher than your target.
- Advance undue cards whose retention is lower than your target.
- Balance the load during rescheduling.
- No Anki on Free Days (such as weekends).
- Disperse Siblings (cards with the same note) to avoid interference & reminder.
中文版请见：FSRS4Anki 使用指北
Preferences > Review > Enable V3 Scheduler
In the deck options, find the Advanced Settings column, and paste the code in fsrs4anki_scheduler.js into the Custom Scheduling field:
Idealy, you've now started using the FSRS4Anki Scheduler. If you're unsure, you can change this part of the code:
const display_memory_state = false;to:
const display_memory_state = true;Then open any deck for review and you'll see:
This shows that your FSRS is running normally. You can then change the code back and the message will no longer display.
Open the optimizer's notebook and click on Open in Colab to run the optimizer on Google Colab. You don't need to configure the coding environment yourself and you can use Google's machines for free (you'll need to register a Google account):
After opening it in Colab, switch to the folder tab. Once the Optimizer connects to Google's machine, you can right-click to upload your deck file/collection file. When exporting these files, make sure to tick "Include scheduling information" and "Support older Anki versions".
After it's uploaded, change the filename in the notebook to the name of your uploaded file. And set your timezone and next_day_starts_at.
Then click "Run All".
Wait for the code to finish in section 2.3, then copy the personalized parameters that were output.
Replace the parameters in the FSRS code you copied earlier.
You can also generate different parameters for different decks and configure them separately in the code. In the default configuration, deckParams already contains three groups of parameters.
The group "global config for FSRS4Anki" is global parameters.
The group "ALL::Learning::English::Reading" are the parameters applied to the deck "ALL::Learning::English::Reading" and its sub-decks.
Similarly, the third group is the parameters applied to the deck "ALL::Archive" and its sub-decks. You can replace these with the decks you want to configure. If you need more, feel free to copy and add them.
const deckParams = [
{
// Default parameters of FSRS4Anki for global
"deckName": "global config for FSRS4Anki",
"w": [1, 1, 5, -0.5, -0.5, 0.2, 1.4, -0.12, 0.8, 2, -0.2, 0.2, 1],
// The above parameters can be optimized via FSRS4Anki optimizer.
// For details about the parameters, please see: https://github.com/open-spaced-repetition/fsrs4anki/wiki/Free-Spaced-Repetition-Scheduler
// User's custom parameters for global
"requestRetention": 0.9, // recommended setting: 0.8 ~ 0.9
"maximumInterval": 36500,
"easyBonus": 1.3,
"hardInterval": 1.2,
// FSRS only modifies the long-term scheduling. So (re)learning steps in deck options work as usual.
// I recommend setting steps shorter than 1 day.
},
{
// Example 1: User's custom parameters for this deck and its sub-decks.
// Need to add <div id=deck deck_name="{{Deck}}"></div> to your card's front template's first line.
"deckName": "ALL::Learning::English::Reading",
"w": [1.1475, 1.401, 5.1483, -1.4221, -1.2282, 0.035, 1.4668, -0.1286, 0.7539, 1.9671, -0.2307, 0.32, 0.9451],
"requestRetention": 0.9,
"maximumInterval": 36500,
"easyBonus": 1.3,
"hardInterval": 1.2,
},
{
// Example 2: User's custom parameters for this deck and its sub-decks.
// Don't omit any keys.
"deckName": "ALL::Archive",
"w": [1.2879, 0.5135, 4.9532, -1.502, -1.0922, 0.0081, 1.3771, -0.0294, 0.6718, 1.8335, -0.4066, 0.7291, 0.5517],
"requestRetention": 0.9,
"maximumInterval": 36500,
"easyBonus": 1.3,
"hardInterval": 1.2,
}
];If there are some decks you don't want to use FSRS with, you can add their names to the skip_decks list.
const skip_decks = ["ALL::Learning::ML::NNDL", "ALL::Learning::English"];Please see: FSRS4Anki Helper
Here collect some questions from issues, forums, and others: FAQ
Some add-ons modify the scheduling of Anki, which would cause conflict with FSRS4Anki scheduler.
| Add-on | Compatible? | Comment |
|---|---|---|
| Advanced Review Bottom Bar | Yes✅ | Please use the latest version. |
| Incremental Reading v4.11.3 (unofficial clone) | No❌ | It shows the interval given by Anki's built-in scheduler, not the custom scheduler. |
| Auto Ease Factor | Yes✅ | Ease Factor doesn't affect the interval given by FSRS. |
| Delay siblings | Yes✅ | Delay siblings will modify the interval give by FSRS. |
| autoLapseNewInterval | Yes✅ | New Interval doesn't affect the interval given by FSRS. |
| Straight Reward | Yes✅ | Ease Factor doesn't affect the interval given by FSRS. |
| Pass/Fail | Yes✅ | Pass is the equivalent of Good. |
Let me know via issues if I miss any add-ons.
You can contribute to FSRS4Anki by beta testing, submitting code, or sharing your data. If you want to share your data with me, please fill this form: https://forms.gle/KaojsBbhMCytaA7h8