Use sm2 retention when deriving memory state

Closes #2702

Cargo.lock

@@ -1477,7 +1477,7 @@ dependencies = [
 [[package]]
 name = "fsrs"
 version = "0.1.0"
-source = "git+https://github.com/open-spaced-repetition/fsrs-rs.git?rev=c34ac397635b6d04fdee07ace9401047f37a5f3e#c34ac397635b6d04fdee07ace9401047f37a5f3e"
+source = "git+https://github.com/open-spaced-repetition/fsrs-rs.git?rev=5089470af3944f7efbf386be09f3858342d4d5af#5089470af3944f7efbf386be09f3858342d4d5af"
 dependencies = [
  "burn",
  "itertools 0.11.0",

Cargo.toml

@@ -36,7 +36,7 @@ rev = "184b2ca50ed39ca43da13f0b830a463861adb9ca"
 
 [workspace.dependencies.fsrs]
 git = "https://github.com/open-spaced-repetition/fsrs-rs.git"
-rev = "c34ac397635b6d04fdee07ace9401047f37a5f3e"
+rev = "5089470af3944f7efbf386be09f3858342d4d5af"
 # path = "../../../fsrs-rs"
 
 [workspace.dependencies]

ftl/core/deck-config.ftl

@@ -331,6 +331,7 @@ deck-config-optimize-button = Optimize
 deck-config-compute-button = Compute
 deck-config-analyze-button = Analyze
 deck-config-desired-retention = Desired retention
+deck-config-sm2-retention = SM2 retention
 deck-config-smaller-is-better = Smaller numbers indicate a better fit to your review history.
 deck-config-steps-too-large-for-fsrs = When FSRS is enabled, learning steps over 1 day are not recommended.
 deck-config-get-params = Get Params

proto/anki/deck_config.proto

@@ -142,6 +142,7 @@ message DeckConfig {
     // for fsrs
     float desired_retention = 37;
     bool reschedule_fsrs_cards = 39;
+    float sm2_retention = 40;
 
     bytes other = 255;
   }

rslib/src/deckconfig/mod.rs

@@ -71,6 +71,7 @@ const DEFAULT_DECK_CONFIG_INNER: DeckConfigInner = DeckConfigInner {
     desired_retention: 0.9,
     other: Vec::new(),
     reschedule_fsrs_cards: false,
+    sm2_retention: 0.9,
 };
 
 impl Default for DeckConfig {
@@ -275,6 +276,7 @@ pub(crate) fn ensure_deck_config_values_valid(config: &mut DeckConfigInner) {
         0.7,
         0.97,
     );
+    ensure_f32_valid(&mut config.sm2_retention, default.sm2_retention, 0.7, 0.97)
 }
 
 fn ensure_f32_valid(val: &mut f32, default: f32, min: f32, max: f32) {

rslib/src/deckconfig/schema11.rs

@@ -73,6 +73,8 @@ pub struct DeckConfSchema11 {
     stop_timer_on_answer: bool,
     #[serde(default)]
     reschedule_fsrs_cards: bool,
+    #[serde(default)]
+    sm2_retention: f32,
 
     #[serde(flatten)]
     other: HashMap<String, Value>,
@@ -263,6 +265,7 @@ impl Default for DeckConfSchema11 {
             fsrs_weights: vec![],
             desired_retention: 0.9,
             reschedule_fsrs_cards: false,
+            sm2_retention: 0.9,
         }
     }
 }
@@ -335,6 +338,7 @@ impl From<DeckConfSchema11> for DeckConfig {
                 fsrs_weights: c.fsrs_weights,
                 desired_retention: c.desired_retention,
                 reschedule_fsrs_cards: c.reschedule_fsrs_cards,
+                sm2_retention: c.sm2_retention,
                 other: other_bytes,
             },
         }
@@ -430,6 +434,7 @@ impl From<DeckConfig> for DeckConfSchema11 {
             fsrs_weights: i.fsrs_weights,
             desired_retention: i.desired_retention,
             reschedule_fsrs_cards: i.reschedule_fsrs_cards,
+            sm2_retention: 0.9,
         }
     }
 }
@@ -454,7 +459,8 @@ static RESERVED_DECKCONF_KEYS: Set<&'static str> = phf_set! {
     "fsrsWeights",
     "desiredRetention",
     "stopTimerOnAnswer",
-    "rescheduleFsrsCards"
+    "rescheduleFsrsCards",
+    "sm2Retention",
 };
 
 static RESERVED_DECKCONF_NEW_KEYS: Set<&'static str> = phf_set! {

rslib/src/deckconfig/update.rs

@@ -236,6 +236,7 @@ impl Collection {
                                     desired_retention: c.inner.desired_retention,
                                     max_interval: c.inner.maximum_review_interval,
                                     reschedule: c.inner.reschedule_fsrs_cards,
+                                    sm2_retention: c.inner.sm2_retention,
                                 })
                             } else {
                                 None

rslib/src/scheduler/answering/mod.rs

@@ -361,8 +361,13 @@ impl Collection {
                 // and will need its initial memory state to be calculated based on review
                 // history.
                 let revlog = self.revlog_for_srs(SearchNode::CardIds(card.id.to_string()))?;
-                let item = single_card_revlog_to_item(&fsrs, revlog, timing.next_day_at);
+                let item = single_card_revlog_to_item(
-                card.set_memory_state(&fsrs, item);
+                    &fsrs,
+                    revlog,
+                    timing.next_day_at,
+                    config.inner.sm2_retention,
+                );
+                card.set_memory_state(&fsrs, item, config.inner.sm2_retention);
             }
             let days_elapsed = self
                 .storage

rslib/src/scheduler/fsrs/memory_state.rs

@@ -30,6 +30,7 @@ pub struct ComputeMemoryProgress {
 pub(crate) struct UpdateMemoryStateRequest {
     pub weights: Weights,
     pub desired_retention: f32,
+    pub sm2_retention: f32,
     pub max_interval: u32,
     pub reschedule: bool,
 }
@@ -57,7 +58,13 @@ impl Collection {
                 None
             };
             let fsrs = FSRS::new(req.as_ref().map(|w| &w.weights[..]).or(Some([].as_slice())))?;
-            let items = fsrs_items_for_memory_state(&fsrs, revlog, timing.next_day_at);
+            let sm2_retention = req.as_ref().map(|w| w.sm2_retention);
+            let items = fsrs_items_for_memory_state(
+                &fsrs,
+                revlog,
+                timing.next_day_at,
+                sm2_retention.unwrap_or(0.9),
+            );
             let desired_retention = req.as_ref().map(|w| w.desired_retention);
             let mut progress = self.new_progress_handler::<ComputeMemoryProgress>();
             progress.update(false, |s| s.total_cards = items.len() as u32)?;
@@ -66,7 +73,7 @@ impl Collection {
                 let mut card = self.storage.get_card(card_id)?.or_not_found(card_id)?;
                 let original = card.clone();
                 if let Some(req) = &req {
-                    card.set_memory_state(&fsrs, item);
+                    card.set_memory_state(&fsrs, item, sm2_retention.unwrap());
                     card.desired_retention = desired_retention;
                     // if rescheduling
                     if let Some(reviews) = &last_reviews {
@@ -127,10 +134,16 @@ impl Collection {
             .get_deck_config(conf_id)?
             .or_not_found(conf_id)?;
         let desired_retention = config.inner.desired_retention;
+        let sm2_retention = config.inner.sm2_retention;
         let fsrs = FSRS::new(Some(&config.inner.fsrs_weights))?;
         let revlog = self.revlog_for_srs(SearchNode::CardIds(card.id.to_string()))?;
-        let item = single_card_revlog_to_item(&fsrs, revlog, self.timing_today()?.next_day_at);
+        let item = single_card_revlog_to_item(
-        card.set_memory_state(&fsrs, item);
+            &fsrs,
+            revlog,
+            self.timing_today()?.next_day_at,
+            sm2_retention,
+        );
+        card.set_memory_state(&fsrs, item, sm2_retention);
         Ok(ComputeMemoryStateResponse {
             state: card.memory_state.map(Into::into),
             desired_retention,
@@ -143,6 +156,7 @@ impl Card {
         &mut self,
         fsrs: &FSRS,
         item: Option<FsrsItemWithStartingState>,
+        sm2_retention: f32,
     ) {
         self.memory_state = item
             .map(|i| fsrs.memory_state(i.item, i.starting_state))
@@ -151,7 +165,11 @@ impl Card {
                     None
                 } else {
                     // no valid revlog entries; infer state from current card state
-                    Some(fsrs.memory_state_from_sm2(self.ease_factor(), self.interval as f32))
+                    Some(fsrs.memory_state_from_sm2(
+                        self.ease_factor(),
+                        self.interval as f32,
+                        sm2_retention,
+                    ))
                 }
             })
             .map(Into::into);
@@ -172,6 +190,7 @@ pub(crate) fn fsrs_items_for_memory_state(
     fsrs: &FSRS,
     revlogs: Vec<RevlogEntry>,
     next_day_at: TimestampSecs,
+    sm2_retention: f32,
 ) -> Vec<(CardId, Option<FsrsItemWithStartingState>)> {
     revlogs
         .into_iter()
@@ -180,7 +199,7 @@ pub(crate) fn fsrs_items_for_memory_state(
         .map(|(card_id, group)| {
             (
                 card_id,
-                single_card_revlog_to_item(fsrs, group.collect(), next_day_at),
+                single_card_revlog_to_item(fsrs, group.collect(), next_day_at, sm2_retention),
             )
         })
         .collect()
@@ -214,6 +233,7 @@ pub(crate) fn single_card_revlog_to_item(
     fsrs: &FSRS,
     entries: Vec<RevlogEntry>,
     next_day_at: TimestampSecs,
+    sm2_retention: f32,
 ) -> Option<FsrsItemWithStartingState> {
     let have_learning = entries
         .iter()
@@ -232,7 +252,7 @@ pub(crate) fn single_card_revlog_to_item(
         };
         let interval = first_review.interval.max(1);
         let starting_state =
-            fsrs.memory_state_from_sm2(ease_factor as f32 / 1000.0, interval as f32);
+            fsrs.memory_state_from_sm2(ease_factor as f32 / 1000.0, interval as f32, sm2_retention);
         let items = single_card_revlog_to_items(entries, next_day_at, false);
         items.and_then(|mut items| {
             let mut item = items.pop().unwrap();
@@ -277,6 +297,7 @@ mod tests {
                 revlog(RevlogReviewKind::Review, 1),
             ],
             TimestampSecs::now(),
+            0.9,
         )
         .unwrap();
         assert_eq!(
@@ -287,7 +308,7 @@ mod tests {
             })
         );
         let mut card = Card::default();
-        card.set_memory_state(&fsrs, Some(item));
+        card.set_memory_state(&fsrs, Some(item), 0.9);
         assert_eq!(
             card.memory_state,
             Some(FsrsMemoryState {
@@ -305,12 +326,13 @@ mod tests {
                 ..revlog(RevlogReviewKind::Review, 100)
             }],
             TimestampSecs::now(),
+            0.9,
         );
         assert!(item.is_none());
         card.interval = 123;
         card.ease_factor = 2000;
         card.ctype = CardType::Review;
-        card.set_memory_state(&fsrs, item);
+        card.set_memory_state(&fsrs, item, 0.9);
         assert_eq!(
             card.memory_state,
             Some(FsrsMemoryState {
@@ -331,7 +353,7 @@ mod tests {
             ease_factor: 1300,
             ..Default::default()
         };
-        card.set_memory_state(&FSRS::new(Some(&[])).unwrap(), None);
+        card.set_memory_state(&FSRS::new(Some(&[])).unwrap(), None, 0.9);
         assert_eq!(
             card.memory_state,
             Some(

ts/deck-options/FsrsOptions.svelte

@@ -214,6 +214,17 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     </SettingTitle>
 </SpinBoxFloatRow>
 
+<SpinBoxFloatRow
+    bind:value={$config.sm2Retention}
+    defaultValue={defaults.sm2Retention}
+    min={0.7}
+    max={0.97}
+>
+    <SettingTitle>
+        {tr.deckConfigSm2Retention()}
+    </SettingTitle>
+</SpinBoxFloatRow>
+
 <div class="ms-1 me-1">
     <WeightsInputRow
         bind:value={$config.fsrsWeights}