From 0e0e3b923890103a24bd92dbdfbc1ffb40163993 Mon Sep 17 00:00:00 2001
From: Luc Mcgrady <lucmcgrady@gmail.com>
Date: Thu, 19 Jun 2025 23:56:03 +0100
Subject: [PATCH] Added: Loss aversion

---
 proto/anki/scheduler.proto            |  3 ++-
 rslib/src/scheduler/fsrs/retention.rs | 14 +++++++++++---
 ts/routes/deck-options/choices.ts     |  4 ++++
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/proto/anki/scheduler.proto b/proto/anki/scheduler.proto
index 2db0b937e..9d1bbdf37 100644
--- a/proto/anki/scheduler.proto
+++ b/proto/anki/scheduler.proto
@@ -391,7 +391,8 @@ message FsrsReview {
 
 enum CMRRTarget {
   memorized = 0;
-  stability = 1;
+  loss_aversion = 1;
+  stability = 2;
 };
 
 message SimulateFsrsReviewRequest {
diff --git a/rslib/src/scheduler/fsrs/retention.rs b/rslib/src/scheduler/fsrs/retention.rs
index d6bdf22bf..b16fa6578 100644
--- a/rslib/src/scheduler/fsrs/retention.rs
+++ b/rslib/src/scheduler/fsrs/retention.rs
@@ -25,7 +25,7 @@ impl Collection {
             };
         }
 
-        let target = req
+        let target_type = req
             .target
             .map(TryInto::try_into)
             .transpose()
@@ -33,8 +33,9 @@ impl Collection {
 
         let days_to_simulate = req.days_to_simulate as f32;
 
-        let target = match target {
+        let target = match target_type {
             Some(CmrrTarget::Memorized) => None,
+            Some(CmrrTarget::LossAversion) => None,
             Some(CmrrTarget::Stability) => {
                 wrap!(move |SimulationResult {
                                 cards,
@@ -57,7 +58,14 @@ impl Collection {
         if req.days_to_simulate == 0 {
             invalid_input!("no days to simulate")
         }
-        let (config, cards) = self.simulate_request_to_config(&req)?;
+        let (mut config, cards) = self.simulate_request_to_config(&req)?;
+
+        if target_type == Some(CmrrTarget::LossAversion) {
+            config.relearning_step_transitions[0][0] *= 2.;
+            config.relearning_step_transitions[1][0] *= 2.;
+            config.relearning_step_transitions[2][0] *= 2.;
+        }
+
         Ok(fsrs
             .optimal_retention(
                 &config,
diff --git a/ts/routes/deck-options/choices.ts b/ts/routes/deck-options/choices.ts
index 380906b44..c4ec7907d 100644
--- a/ts/routes/deck-options/choices.ts
+++ b/ts/routes/deck-options/choices.ts
@@ -206,6 +206,10 @@ export function CMRRTargetChoices(): Choice<CMRRTarget>[] {
             label: "Memorized (Default)",
             value: CMRRTarget.memorized,
         },
+        {
+            label: "Memorized (Double cost)",
+            values: CMRRTarget.loss_aversion,
+        },
         {
             label: "Stability (Experimental)",
             value: CMRRTarget.stability,