consider rating regulator orthogonal, make conversions more explicit

niklasf · Nov 2, 2024 · 08dab0a · 08dab0a
1 parent f6b67bd
commit 08dab0a
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Showing 4 changed files with 13 additions and 46 deletions.
diff --git a/research/src/bin/replay_encounters.rs b/research/src/bin/replay_encounters.rs
@@ -479,7 +479,6 @@ fn main() -> Result<(), Box<dyn StdError>> {
                         for &rating_periods_per_day in &opt.rating_periods_per_day {
                             experiments.push(Experiment {
                                 rating_system: RatingSystem::builder()
-                                    .rating_regulator_factor(1.0)
                                     .min_rating(RatingScalar(-f64::INFINITY))
                                     .max_rating(RatingScalar(f64::INFINITY))
                                     .min_deviation(RatingDifference(min_deviation))

diff --git a/src/internal_rating.rs b/src/internal_rating.rs
@@ -3,24 +3,15 @@ use crate::rating::RatingDifference;
 #[derive(Debug, Clone, Copy)]
 pub(crate) struct InternalRatingDifference(pub f64);
 
-impl From<InternalRatingDifference> for f64 {
-    #[inline]
-    fn from(InternalRatingDifference(difference): InternalRatingDifference) -> f64 {
-        difference
-    }
-}
-
-impl From<RatingDifference> for InternalRatingDifference {
-    #[inline]
-    fn from(RatingDifference(difference): RatingDifference) -> InternalRatingDifference {
+impl InternalRatingDifference {
+    pub fn from_external(
+        RatingDifference(difference): RatingDifference,
+    ) -> InternalRatingDifference {
         InternalRatingDifference(difference / INTERNAL_RATING_SCALE)
     }
-}
 
-impl From<InternalRatingDifference> for RatingDifference {
-    #[inline]
-    fn from(InternalRatingDifference(difference): InternalRatingDifference) -> RatingDifference {
-        RatingDifference(difference * INTERNAL_RATING_SCALE)
+    pub fn to_external(self) -> RatingDifference {
+        RatingDifference(self.0 * INTERNAL_RATING_SCALE)
     }
 }
 

diff --git a/src/rating.rs b/src/rating.rs
@@ -102,7 +102,7 @@ impl RatingDifference {
 
     #[inline]
     pub(crate) fn to_internal(self) -> InternalRatingDifference {
-        InternalRatingDifference::from(self)
+        InternalRatingDifference::from_external(self)
     }
 }
 

diff --git a/src/rating_system.rs b/src/rating_system.rs
@@ -40,7 +40,6 @@ pub struct RatingSystemBuilder {
     max_convergence_iterations: u32,
 
     max_rating_delta: RatingDifference,
-    rating_regulator_factor: f64,
 }
 
 impl RatingSystemBuilder {
@@ -137,14 +136,6 @@ impl RatingSystemBuilder {
         self
     }
 
-    /// Set the factor by which rating gains (but not losses) are multiplied.
-    /// The default is `1.015`.
-    pub fn rating_regulator_factor(&mut self, rating_regulator_factor: f64) -> &mut Self {
-        assert!(rating_regulator_factor >= 0.0);
-        self.rating_regulator_factor = rating_regulator_factor;
-        self
-    }
-
     pub fn build(&self) -> RatingSystem {
         assert!(self.min_rating <= self.max_rating);
         assert!(self.min_deviation <= self.max_deviation);
@@ -170,7 +161,6 @@ impl RatingSystemBuilder {
             max_convergence_iterations: self.max_convergence_iterations,
 
             max_rating_delta: self.max_rating_delta,
-            rating_regulator_factor: self.rating_regulator_factor,
         }
     }
 }
@@ -202,7 +192,6 @@ pub struct RatingSystem {
     max_convergence_iterations: u32,
 
     max_rating_delta: RatingDifference,
-    rating_regulator_factor: f64,
 }
 
 impl Default for RatingSystem {
@@ -238,7 +227,6 @@ impl RatingSystem {
             max_convergence_iterations: 1000,
 
             max_rating_delta: RatingDifference(700.0),
-            rating_regulator_factor: 1.015,
         }
     }
 
@@ -298,10 +286,6 @@ impl RatingSystem {
         self.max_rating_delta
     }
 
-    pub fn rating_regulator_factor(&self) -> f64 {
-        self.rating_regulator_factor
-    }
-
     /// Construct an initial rating for a new player.
     pub fn new_rating(&self) -> Rating {
         Rating {
@@ -319,11 +303,12 @@ impl RatingSystem {
     pub fn preview_deviation(&self, rating: &Rating, at: Instant) -> RatingDifference {
         let rating = self.clamp_rating(rating);
 
-        RatingDifference::from(new_deviation(
+        new_deviation(
             rating.deviation.to_internal(),
             rating.volatility,
             at.elapsed_since(rating.at),
-        ))
+        )
+        .to_external()
         .clamp(self.min_deviation, self.max_deviation)
     }
 
@@ -460,23 +445,15 @@ impl RatingSystem {
         // Step 8
         Ok(self.clamp_rating(&Rating {
             rating: us.rating
-                + self
-                    .regulate(RatingDifference::from(mu_prime_diff))
+                + mu_prime_diff
+                    .to_external()
                     .clamp(-self.max_rating_delta, self.max_rating_delta),
-            deviation: RatingDifference::from(phi_prime),
+            deviation: phi_prime.to_external(),
             volatility: sigma_prime,
             at: now,
         }))
     }
 
-    fn regulate(&self, diff: RatingDifference) -> RatingDifference {
-        if diff > RatingDifference(0.0) {
-            self.rating_regulator_factor * diff
-        } else {
-            diff
-        }
-    }
-
     fn clamp_rating(&self, rating: &Rating) -> Rating {
         Rating {
             rating: rating.rating.clamp(self.min_rating, self.max_rating),