Protected Optional_seedProtectedintervalProtectedparamGet the parameters of the algorithm.
-Set the parameters of the algorithm.
+Protected Optional_seedProtectedintervalProtectedparamGet the parameters of the algorithm.
+Set the parameters of the algorithm.
Partial
If fuzzing is disabled or ivl is less than 2.5, it returns the original interval.
+If fuzzing is disabled or ivl is less than 2.5, it returns the original interval.
The interval to be fuzzed.
t days since the last review
Optionalenable_fuzz: booleanThis adds a small random delay to the new interval time to prevent cards from sticking together and always being reviewed on the same day.
0<request_retention<=1,Requested retention rate
+0<request_retention<=1,Requested retention rate
https://github.com/open-spaced-repetition/fsrs4anki/wiki/The-Algorithm#fsrs-45
The formula used is: $$I(r,s) = (r^{\frac{1}{DECAY}} - 1) / FACTOR \times s$$
Requested retention rate should be in the range (0,1]
-Card to be processed
Current time or scheduled time
Should the review count information(reps,lapses) be reset. (Optional)
OptionalafterHandler: ((recordLogItem: RecordLogItem) => R)Convert the result to another type. (Optional)
@@ -55,33 +55,33 @@interface RepeatRecordLog {
card: CardUnChecked; //see method: createEmptyCard
log: RevLogUnchecked; //see method: fsrs.repeat()
}
function forgetAfterHandler(recordLogItem: RecordLogItem): RepeatRecordLog {
return {
card: {
...(recordLogItem.card as Card & { cid: string }),
due: recordLogItem.card.due.getTime(),
state: State[recordLogItem.card.state] as StateType,
last_review: recordLogItem.card.last_review
? recordLogItem.card.last_review!.getTime()
: null,
},
log: {
...recordLogItem.log,
cid: (recordLogItem.card as Card & { cid: string }).cid,
due: recordLogItem.log.due.getTime(),
review: recordLogItem.log.review.getTime(),
state: State[recordLogItem.log.state] as StateType,
rating: Rating[recordLogItem.log.rating] as RatingType,
},
};
}
const now = new Date();
const f = fsrs();
const emptyCardFormAfterHandler = createEmptyCard(now, cardAfterHandler); //see method: createEmptyCard
const repeatFormAfterHandler = f.repeat(emptyCardFormAfterHandler, now, repeatAfterHandler); //see method: fsrs.repeat()
const { card } = repeatFormAfterHandler[Rating.Hard];
const forgetFromAfterHandler = f.forget(card, date_scheduler(now, 1, true), false, forgetAfterHandler);
The formula used is : $$R(t,S) = (1 + \text{FACTOR} \times \frac{t}{9 \cdot S})^{\text{DECAY}}$$
t days since the last review
Stability (interval when R=90%)
r Retrievability (probability of recall)
-Get the retrievability of the card
+The retrievability of the card,if format is true, the result is a string, otherwise it is a number
+The formula used is : $$D_0(G) = w_4 - e^{(G-1) \cdot w_5} + 1 $$ $$D_0 = \min \lbrace \max \lbrace D_0(G),1 \rbrace,10 \rbrace$$ where the $$D_0(1)=w_4$$ when the first rating is good.
Grade (rating at Anki) [1.again,2.hard,3.good,4.easy]
Difficulty $$D \in [1,10]$$
-The formula used is : +
The formula used is : $$ S_0(G) = w_{G-1}$$ $$S_0 = \max \lbrace S_0,0.1\rbrace $$
Grade (rating at Anki) [1.again,2.hard,3.good,4.easy]
Stability (interval when R=90%)
-The formula used is : +
Display the collection of cards and logs for the card scheduled at the current time, after applying a specific grade rating.
+Display the collection of cards and logs for the card scheduled at the current time, after applying a specific grade rating.
Card to be processed
Current time or scheduled time
Rating of the review (Again, Hard, Good, Easy)
@@ -92,34 +92,34 @@interface RevLogUnchecked
extends Omit<ReviewLog, "due" | "review" | "state" | "rating"> {
cid: string;
due: Date | number;
state: StateType;
review: Date | number;
rating: RatingType;
}
interface NextRecordLog {
card: CardUnChecked; //see method: createEmptyCard
log: RevLogUnchecked;
}
function nextAfterHandler(recordLogItem: RecordLogItem) {
const recordItem = {
card: {
...(recordLogItem.card as Card & { cid: string }),
due: recordLogItem.card.due.getTime(),
state: State[recordLogItem.card.state] as StateType,
last_review: recordLogItem.card.last_review
? recordLogItem.card.last_review!.getTime()
: null,
},
log: {
...recordLogItem.log,
cid: (recordLogItem.card as Card & { cid: string }).cid,
due: recordLogItem.log.due.getTime(),
review: recordLogItem.log.review.getTime(),
state: State[recordLogItem.log.state] as StateType,
rating: Rating[recordLogItem.log.rating] as RatingType,
},
};
return recordItem
}
const card: Card = createEmptyCard(new Date(), cardAfterHandler); //see method: createEmptyCard
const f = fsrs();
const recordLogItem = f.repeat(card, new Date(), Rating.Again, nextAfterHandler);
The formula used is : $$\text{next}_d = D - w_6 \cdot (g - 3)$$ $$D^\prime(D,R) = w_7 \cdot D_0(4) +(1 - w_7) \cdot \text{next}_d$$
Difficulty $$D \in [1,10]$$
Grade (rating at Anki) [1.again,2.hard,3.good,4.easy]
$$\text{next}_D$$
-The formula used is : +
The formula used is : $$S^\prime_f(D,S,R) = w_{11}\cdot D^{-w_{12}}\cdot ((S+1)^{w_{13}}-1) \cdot e^{w_{14}\cdot(1-R)}$$
Difficulty D \in [1,10]
Stability (interval when R=90%)
Retrievability (probability of recall)
S^\prime_f new stability after forgetting
-Stability (interval when R=90%)
+Stability (interval when R=90%)
t days since the last review
This adds a small random delay to the new interval time to prevent cards from sticking together and always being reviewed on the same day.
The formula used is : FSRSAlgorithm.calculate_interval_modifier
-The formula used is : $$S^\prime_r(D,S,R,G) = S\cdot(e^{w_8}\cdot (11-D)\cdot S^{-w_9}\cdot(e^{w_{10}\cdot(1-R)}-1)\cdot w_{15}(\text{if} G=2) \cdot w_{16}(\text{if} G=4)+1)$$
Difficulty D \in [1,10]
Stability (interval when R=90%)
Retrievability (probability of recall)
Grade (Rating[0.again,1.hard,2.good,3.easy])
S^\prime_r new stability after recall
-The formula used is : +
The formula used is : $$S^\prime_s(S,G) = S \cdot e^{w_{17} \cdot (G-3+w_{18})}$$
Stability (interval when R=90%)
Grade (Rating[0.again,1.hard,2.good,3.easy])
-Protectedparams_Protectedparams_Display the collection of cards and logs for the four scenarios after scheduling the card at the current time.
Card to be processed
Current time or scheduled time
OptionalafterHandler: ((recordLog: IPreview) => R)Convert the result to another type. (Optional)
@@ -129,12 +129,12 @@interface RevLogUnchecked
extends Omit<ReviewLog, "due" | "review" | "state" | "rating"> {
cid: string;
due: Date | number;
state: StateType;
review: Date | number;
rating: RatingType;
}
interface RepeatRecordLog {
card: CardUnChecked; //see method: createEmptyCard
log: RevLogUnchecked;
}
function repeatAfterHandler(recordLog: RecordLog) {
const record: { [key in Grade]: RepeatRecordLog } = {} as {
[key in Grade]: RepeatRecordLog;
};
for (const grade of Grades) {
record[grade] = {
card: {
...(recordLog[grade].card as Card & { cid: string }),
due: recordLog[grade].card.due.getTime(),
state: State[recordLog[grade].card.state] as StateType,
last_review: recordLog[grade].card.last_review
? recordLog[grade].card.last_review!.getTime()
: null,
},
log: {
...recordLog[grade].log,
cid: (recordLog[grade].card as Card & { cid: string }).cid,
due: recordLog[grade].log.due.getTime(),
review: recordLog[grade].log.review.getTime(),
state: State[recordLog[grade].log.state] as StateType,
rating: Rating[recordLog[grade].log.rating] as RatingType,
},
};
}
return record;
}
const card: Card = createEmptyCard(new Date(), cardAfterHandler); //see method: createEmptyCard
const f = fsrs();
const recordLog = f.repeat(card, new Date(), repeatAfterHandler);
scheduled card collection
+scheduled card collection
Reschedule options,fuzz is enabled by default.If the type of due is not Date, please implement dataHandler.
type CardType = Card & {
cid: number;
};
const reviewCard: CardType = {
cid: 1,
due: new Date("2024-03-17 04:43:02"),
stability: 48.26139059062234,
difficulty: 5.67,
elapsed_days: 18,
scheduled_days: 51,
reps: 8,
lapses: 1,
state: State.Review,
last_review: new Date("2024-01-26 04:43:02"),
};
const f = fsrs();
const reschedule_cards = f.reschedule([reviewCard]);
const now = new Date();
const f = fsrs();
const emptyCardFormAfterHandler = createEmptyCard(now);
const repeatFormAfterHandler = f.repeat(emptyCardFormAfterHandler, now);
const { card, log } = repeatFormAfterHandler[Rating.Hard];
const rollbackFromAfterHandler = f.rollback(card, log);
@@ -143,4 +143,4 @@ ExampleExample
const now = new Date();
const f = fsrs();
const emptyCardFormAfterHandler = createEmptyCard(now, cardAfterHandler); //see method: createEmptyCard
const repeatFormAfterHandler = f.repeat(emptyCardFormAfterHandler, now, repeatAfterHandler); //see method: fsrs.repeat()
const { card, log } = repeatFormAfterHandler[Rating.Hard];
const rollbackFromAfterHandler = f.rollback(card, log, cardAfterHandler);
-
See
https://github.com/open-spaced-repetition/fsrs4anki/wiki/The-Algorithm#fsrs-45
-