From 0718de4acc18df39152fc55d6bd279af56d7e2af Mon Sep 17 00:00:00 2001
From: Justin Bedo <cu@cua0.org>
Date: Tue, 17 Jan 2023 09:12:18 +1100
Subject: add some strictness

---
 src/PPL/Internal.hs | 4 ++--
 src/PPL/Sampling.hs | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/PPL/Internal.hs b/src/PPL/Internal.hs
index 201a3aa..d927508 100644
--- a/src/PPL/Internal.hs
+++ b/src/PPL/Internal.hs
@@ -18,7 +18,7 @@ import Control.Monad.IO.Class
 
 -- Reimplementation of the LazyPPL monads to avoid some dependencies
 
-data Tree = Tree Double [Tree]
+data Tree = Tree !Double [Tree]
 
 split :: Tree -> (Tree, Tree)
 split (Tree r (t : ts)) = (t, Tree r ts)
@@ -61,7 +61,7 @@ newtype Meas a = Meas (WriterT (Product (Log Double)) Prob a)
 score :: Double -> Meas ()
 score = scoreLog . Exp . log . max eps
   where
-    eps = $(TH.lift (until ((== 1) . (1 +)) (/ 2) (1 :: Double))) -- machine epsilon, force compile time eval
+    eps = $(TH.lift (2 * until ((== 1) . (1 +)) (/ 2) (1 :: Double))) -- machine epsilon, force compile time eval
 
 {-# INLINE scoreLog #-}
 scoreLog :: Log Double -> Meas ()
diff --git a/src/PPL/Sampling.hs b/src/PPL/Sampling.hs
index a3f38db..1d20838 100644
--- a/src/PPL/Sampling.hs
+++ b/src/PPL/Sampling.hs
@@ -42,7 +42,7 @@ mh p m = do
           ratio = w' / w
           (Exp . log -> r, g3) = random g2
       put g3
-      pure $
+      pure $!
         if r < ratio
           then (t', x', w')
           else (t, x, w)
-- 
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