add decay to hit-rate estimation

IntersectMBO · Oct 23, 2020 · d721a9d · d721a9d
1 parent ceb5d0e
commit d721a9d
Showing 1 changed file with 12 additions and 2 deletions.
diff --git a/shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/LedgerState.hs b/shelley/chain-and-ledger/executable-spec/src/Shelley/Spec/Ledger/LedgerState.hs
@@ -183,7 +183,8 @@ import Shelley.Spec.Ledger.PParams
     emptyPParams,
   )
 import Shelley.Spec.Ledger.Rewards
-  ( Likelihood,
+  ( Likelihood (..),
+    LogWeight (..),
     NonMyopic (..),
     emptyNonMyopic,
     reward,
@@ -1047,9 +1048,18 @@ updateNonMypopic nm rPot newLikelihoods =
     }
   where
     history = likelihoodsNM nm
-    performance kh newPerf = fromMaybe mempty (Map.lookup kh history) <> newPerf
+    performance kh newPerf =
+      fromMaybe
+        mempty
+        (applyDecay 0.9 <$> Map.lookup kh history)
+        <> newPerf
     updatedLikelihoods = Map.mapWithKey performance newLikelihoods
 
+applyDecay :: Float -> Likelihood -> Likelihood
+applyDecay decay (Likelihood logWeights) = Likelihood $ mul decay <$> logWeights
+  where
+    mul x (LogWeight f) = LogWeight (x * f)
+
 -- | Create a reward update
 createRUpd ::
   EpochSize ->