diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -5,6 +5,11 @@
 ## Unreleased changes
 
 
+## 0.8.3.0
+
+-   Fix auto tuning with MC3 algorithm.
+
+
 ## 0.8.1.0
 
 -   Automatic intermediate tuning for HMC and NUTS.
@@ -161,7 +166,7 @@
 ## 0.2.4
 
 -   **Change order of arguments for proposals**.
--   ’slideStem’ was renamed to ’slideBranch’.
+-   'slideStem' was renamed to 'slideBranch'.
 -   Change ProposalSimple from newtype to type.
 -   Contravariant instances of parameter and batch monitors. Use `(>$<)` instead
     of `(@.)` and `(@#)`.
diff --git a/bench/Bench.hs b/bench/Bench.hs
--- a/bench/Bench.hs
+++ b/bench/Bench.hs
@@ -21,7 +21,7 @@
 import Poisson
 import System.Random.Stateful
 
-gammaBenchG :: RealFloat a => (a -> a) -> [a] -> a
+gammaBenchG :: (RealFloat a) => (a -> a) -> [a] -> a
 gammaBenchG f = foldl' (\acc x -> acc + f x) 0
 {-# SPECIALIZE gammaBenchG :: (Double -> Double) -> [Double] -> Double #-}
 
diff --git a/mcmc.cabal b/mcmc.cabal
--- a/mcmc.cabal
+++ b/mcmc.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               mcmc
-version:            0.8.2.0
+version:            0.8.3.0
 synopsis:           Sample from a posterior using Markov chain Monte Carlo
 description:
   Please see the README on GitHub at <https://github.com/dschrempf/mcmc#readme>
diff --git a/src/Mcmc/Acceptance.hs b/src/Mcmc/Acceptance.hs
--- a/src/Mcmc/Acceptance.hs
+++ b/src/Mcmc/Acceptance.hs
@@ -78,7 +78,7 @@
 newtype Acceptances k = Acceptances {fromAcceptances :: M.Map k Acceptance}
   deriving (Eq, Show)
 
-instance ToJSONKey k => ToJSON (Acceptances k) where
+instance (ToJSONKey k) => ToJSON (Acceptances k) where
   toJSON (Acceptances m) = toJSON m
   toEncoding (Acceptances m) = toEncoding m
 
@@ -88,17 +88,17 @@
 -- | In the beginning there was the Word.
 --
 -- Initialize an empty storage of accepted/rejected values.
-emptyA :: Ord k => [k] -> Acceptances k
+emptyA :: (Ord k) => [k] -> Acceptances k
 emptyA ks = Acceptances $ M.fromList [(k, A noCounts Nothing) | k <- ks]
   where
     noCounts = AcceptanceCounts 0 0
 
 -- | For key @k@, add an accept.
-pushAccept :: Ord k => Maybe AcceptanceRates -> k -> Acceptances k -> Acceptances k
+pushAccept :: (Ord k) => Maybe AcceptanceRates -> k -> Acceptances k -> Acceptances k
 pushAccept mr k = Acceptances . M.adjust (addAccept mr) k . fromAcceptances
 
 -- | For key @k@, add a reject.
-pushReject :: Ord k => Maybe AcceptanceRates -> k -> Acceptances k -> Acceptances k
+pushReject :: (Ord k) => Maybe AcceptanceRates -> k -> Acceptances k -> Acceptances k
 pushReject mr k = Acceptances . M.adjust (addReject mr) k . fromAcceptances
 
 -- | Reset acceptance specification.
@@ -109,7 +109,7 @@
     ResetExpectedRatesOnly
 
 -- | Reset acceptance counts.
-resetA :: Ord k => ResetAcceptance -> Acceptances k -> Acceptances k
+resetA :: (Ord k) => ResetAcceptance -> Acceptances k -> Acceptances k
 resetA ResetEverything = emptyA . M.keys . fromAcceptances
 resetA ResetExpectedRatesOnly = Acceptances . M.map f . fromAcceptances
   where
@@ -133,7 +133,7 @@
 -- Return 'Nothing' if no proposals have been accepted or rejected (division by
 -- zero).
 acceptanceRate ::
-  Ord k =>
+  (Ord k) =>
   k ->
   Acceptances k ->
   -- | (nAccepts, nRejects, actualRate, expectedRate)
diff --git a/src/Mcmc/Algorithm/MC3.hs b/src/Mcmc/Algorithm/MC3.hs
--- a/src/Mcmc/Algorithm/MC3.hs
+++ b/src/Mcmc/Algorithm/MC3.hs
@@ -176,7 +176,7 @@
     mc3Generator :: IOGenM StdGen
   }
 
-instance ToJSON a => Algorithm (MC3 a) where
+instance (ToJSON a) => Algorithm (MC3 a) where
   aName = const "Metropolis-coupled Markov chain Monte Carlo (MC3)"
   aIteration = mc3Iteration
   aIsInvalidState = mc3IsInvalidState
@@ -311,7 +311,7 @@
 
 -- | Save an MC3 algorithm.
 mc3Save ::
-  ToJSON a =>
+  (ToJSON a) =>
   AnalysisName ->
   MC3 a ->
   IO ()
@@ -325,7 +325,7 @@
 --
 -- See 'Mcmc.Mcmc.mcmcContinue'.
 mc3Load ::
-  FromJSON a =>
+  (FromJSON a) =>
   PriorFunction a ->
   LikelihoodFunction a ->
   Cycle a ->
@@ -419,7 +419,7 @@
   where
     g = mc3Generator a
 
-mc3IsInvalidState :: ToJSON a => MC3 a -> Bool
+mc3IsInvalidState :: (ToJSON a) => MC3 a -> Bool
 mc3IsInvalidState a = V.any aIsInvalidState mhgs
   where
     mhgs = mc3MHGChains a
@@ -427,7 +427,7 @@
 -- NOTE: 'mc3Iterate' is actually not parallel, but concurrent because of the IO
 -- constraint of the mutable trace.
 mc3Iterate ::
-  ToJSON a =>
+  (ToJSON a) =>
   IterationMode ->
   ParallelizationMode ->
   MC3 a ->
@@ -477,7 +477,7 @@
     rNew = (brOld / blOld) ** xi
     brNew = blNew * rNew
 
-mc3AutoTune :: ToJSON a => TuningType -> Int -> MC3 a -> IO (MC3 a)
+mc3AutoTune :: (ToJSON a) => TuningType -> Int -> MC3 a -> IO (MC3 a)
 mc3AutoTune b l a = do
   -- 1. Auto tune all chains.
   mhgs' <- V.mapM (aAutoTune b l) $ mc3MHGChains a
@@ -510,9 +510,12 @@
             (setReciprocalTemperature coldPrF coldLhF)
             (V.convert $ U.tail bs')
             (V.tail mhgs')
-  return $ a {mc3MHGChains = mhgs'', mc3ReciprocalTemperatures = bs'}
+  return $
+    if b == NormalTuningFastProposalsOnly || b == NormalTuningAllProposals
+      then a {mc3MHGChains = mhgs'', mc3ReciprocalTemperatures = bs'}
+      else a {mc3MHGChains = mhgs''}
 
-mc3ResetAcceptance :: ToJSON a => ResetAcceptance -> MC3 a -> MC3 a
+mc3ResetAcceptance :: (ToJSON a) => ResetAcceptance -> MC3 a -> MC3 a
 mc3ResetAcceptance x a = a'
   where
     -- 1. Reset acceptance of all chains.
@@ -522,7 +525,7 @@
     --
     a' = a {mc3MHGChains = mhgs', mc3SwapAcceptances = ac'}
 
-mc3CleanAfterBurnIn :: ToJSON a => TraceLength -> MC3 a -> IO (MC3 a)
+mc3CleanAfterBurnIn :: (ToJSON a) => TraceLength -> MC3 a -> IO (MC3 a)
 mc3CleanAfterBurnIn tl a = do
   cs' <- V.mapM (aCleanAfterBurnIn tl) cs
   pure $ a {mc3MHGChains = cs'}
@@ -536,7 +539,7 @@
 -- - The combined acceptance rate of proposals within the hot chains.
 --
 -- - The temperatures of the chains and the acceptance rates of the state swaps.
-mc3SummarizeCycle :: ToJSON a => IterationMode -> MC3 a -> BL.ByteString
+mc3SummarizeCycle :: (ToJSON a) => IterationMode -> MC3 a -> BL.ByteString
 mc3SummarizeCycle m a =
   BL.intercalate "\n" $
     [ "MC3: Cycle of cold chain.",
@@ -585,7 +588,7 @@
     proposalHLine = BL.replicate (BL.length proposalHeader) '-'
 
 -- No extra monitors are opened.
-mc3OpenMonitors :: ToJSON a => AnalysisName -> ExecutionMode -> MC3 a -> IO (MC3 a)
+mc3OpenMonitors :: (ToJSON a) => AnalysisName -> ExecutionMode -> MC3 a -> IO (MC3 a)
 mc3OpenMonitors nm em a = do
   mhgs' <- V.imapM mhgOpenMonitors (mc3MHGChains a)
   return $ a {mc3MHGChains = mhgs'}
@@ -598,7 +601,7 @@
         suf = printf "%02d" i
 
 mc3ExecuteMonitors ::
-  ToJSON a =>
+  (ToJSON a) =>
   Verbosity ->
   -- Starting time.
   UTCTime ->
@@ -613,10 +616,10 @@
     -- All other chains are to be quiet.
     f _ = aExecuteMonitors Quiet t0 iTotal
 
-mc3StdMonitorHeader :: ToJSON a => MC3 a -> BL.ByteString
+mc3StdMonitorHeader :: (ToJSON a) => MC3 a -> BL.ByteString
 mc3StdMonitorHeader = aStdMonitorHeader . V.head . mc3MHGChains
 
-mc3CloseMonitors :: ToJSON a => MC3 a -> IO (MC3 a)
+mc3CloseMonitors :: (ToJSON a) => MC3 a -> IO (MC3 a)
 mc3CloseMonitors a = do
   mhgs' <- V.mapM aCloseMonitors $ mc3MHGChains a
   return $ a {mc3MHGChains = mhgs'}
diff --git a/src/Mcmc/Algorithm/MHG.hs b/src/Mcmc/Algorithm/MHG.hs
--- a/src/Mcmc/Algorithm/MHG.hs
+++ b/src/Mcmc/Algorithm/MHG.hs
@@ -57,7 +57,7 @@
 -- | The MHG algorithm.
 newtype MHG a = MHG {fromMHG :: Chain a}
 
-instance ToJSON a => Algorithm (MHG a) where
+instance (ToJSON a) => Algorithm (MHG a) where
   aName = const "Metropolis-Hastings-Green (MHG)"
   aIteration = iteration . fromMHG
   aIsInvalidState = mhgIsInvalidState
@@ -121,7 +121,7 @@
 
 -- | Save an MHG algorithm.
 mhgSave ::
-  ToJSON a =>
+  (ToJSON a) =>
   AnalysisName ->
   MHG a ->
   IO ()
@@ -135,7 +135,7 @@
 --
 -- See 'Mcmc.Mcmc.mcmcContinue'.
 mhgLoad ::
-  FromJSON a =>
+  (FromJSON a) =>
   PriorFunction a ->
   LikelihoodFunction a ->
   Cycle a ->
@@ -151,7 +151,7 @@
 -- Useful when restarting a run with changed prior function, likelihood function
 -- or proposals. Use with care!
 mhgLoadUnsafe ::
-  FromJSON a =>
+  (FromJSON a) =>
   PriorFunction a ->
   LikelihoodFunction a ->
   Cycle a ->
@@ -162,7 +162,7 @@
 
 -- Nice type :-).
 mhgLoadWith ::
-  FromJSON a =>
+  (FromJSON a) =>
   (PriorFunction a -> LikelihoodFunction a -> Cycle a -> Monitor a -> SavedChain a -> IO (Chain a)) ->
   PriorFunction a ->
   LikelihoodFunction a ->
diff --git a/src/Mcmc/Chain/Link.hs b/src/Mcmc/Chain/Link.hs
--- a/src/Mcmc/Chain/Link.hs
+++ b/src/Mcmc/Chain/Link.hs
@@ -34,16 +34,16 @@
   }
   deriving (Eq, Ord, Show, Read)
 
-instance ToJSON a => ToJSON (Link a) where
+instance (ToJSON a) => ToJSON (Link a) where
   toJSON (Link x (Exp p) (Exp l)) = object ["s" .= x, "p" .= p, "l" .= l]
   toEncoding (Link x (Exp p) (Exp l)) = pairs ("s" .= x <> "p" .= p <> "l" .= l)
 
-link :: FromJSON a => Object -> Parser (Link a)
+link :: (FromJSON a) => Object -> Parser (Link a)
 link v = do
   s <- v .: "s"
   p <- v .: "p"
   l <- v .: "l"
   return $ Link s (Exp p) (Exp l)
 
-instance FromJSON a => FromJSON (Link a) where
+instance (FromJSON a) => FromJSON (Link a) where
   parseJSON = withObject "Link" link
diff --git a/src/Mcmc/Cycle.hs b/src/Mcmc/Cycle.hs
--- a/src/Mcmc/Cycle.hs
+++ b/src/Mcmc/Cycle.hs
@@ -126,7 +126,7 @@
   deriving (Eq)
 
 -- | Replicate 'Proposal's according to their weights and possibly shuffle them.
-prepareProposals :: StatefulGen g m => IterationMode -> Cycle a -> g -> m [Proposal a]
+prepareProposals :: (StatefulGen g m) => IterationMode -> Cycle a -> g -> m [Proposal a]
 prepareProposals m (Cycle xs o _ _) g =
   if null ps
     then
diff --git a/src/Mcmc/Environment.hs b/src/Mcmc/Environment.hs
--- a/src/Mcmc/Environment.hs
+++ b/src/Mcmc/Environment.hs
@@ -39,7 +39,7 @@
   }
   deriving (Eq)
 
-instance HasExecutionMode s => HasExecutionMode (Environment s) where
+instance (HasExecutionMode s) => HasExecutionMode (Environment s) where
   getExecutionMode = getExecutionMode . settings
 
 instance HasLock (Environment s) where
@@ -51,10 +51,10 @@
 instance HasStartingTime (Environment s) where
   getStartingTime = startingTime
 
-instance HasLogMode s => HasLogMode (Environment s) where
+instance (HasLogMode s) => HasLogMode (Environment s) where
   getLogMode = getLogMode . settings
 
-instance HasVerbosity s => HasVerbosity (Environment s) where
+instance (HasVerbosity s) => HasVerbosity (Environment s) where
   getVerbosity = getVerbosity . settings
 
 -- | Initialize the environment.
diff --git a/src/Mcmc/Internal/Shuffle.hs b/src/Mcmc/Internal/Shuffle.hs
--- a/src/Mcmc/Internal/Shuffle.hs
+++ b/src/Mcmc/Internal/Shuffle.hs
@@ -26,12 +26,12 @@
 -- vectors.
 
 -- | Shuffle a vector.
-shuffle :: StatefulGen g m => [a] -> g -> m [a]
+shuffle :: (StatefulGen g m) => [a] -> g -> m [a]
 shuffle xs = grabble xs (length xs)
 
 -- @grabble xs m n@ is /O(m*n')/, where @n' = min n (length xs)@. Choose @n'@
 -- elements from @xs@, without replacement, and that @m@ times.
-grabble :: StatefulGen g m => [a] -> Int -> g -> m [a]
+grabble :: (StatefulGen g m) => [a] -> Int -> g -> m [a]
 grabble xs m gen = do
   swaps <- forM [0 .. min (l - 1) m] $ \i -> do
     j <- uniformRM (i, l) gen
diff --git a/src/Mcmc/Internal/SpecFunctions.hs b/src/Mcmc/Internal/SpecFunctions.hs
--- a/src/Mcmc/Internal/SpecFunctions.hs
+++ b/src/Mcmc/Internal/SpecFunctions.hs
@@ -25,10 +25,10 @@
 import Numeric.SpecFunctions
 import Unsafe.Coerce
 
-mSqrtEpsG :: RealFloat a => a
+mSqrtEpsG :: (RealFloat a) => a
 mSqrtEpsG = 1.4901161193847656e-8
 
-mEulerMascheroniG :: RealFloat a => a
+mEulerMascheroniG :: (RealFloat a) => a
 mEulerMascheroniG = 0.5772156649015328606065121
 
 -- | Generalized version of the log gamma distribution. See
@@ -40,7 +40,7 @@
 {-# SPECIALIZE logGammaG :: Double -> Double #-}
 
 -- See 'Numeric.SpecFunctions.logGamma'.
-logGammaNonDouble :: RealFloat a => a -> a
+logGammaNonDouble :: (RealFloat a) => a -> a
 logGammaNonDouble z
   | z <= 0 = 1 / 0
   | z < mSqrtEpsG = log (1 / z - mEulerMascheroniG)
@@ -51,7 +51,7 @@
   | z < 15 = lgammaSmallG z
   | otherwise = lanczosApproxG z
 
-lgamma1_15G :: RealFloat a => a -> a -> a
+lgamma1_15G :: (RealFloat a) => a -> a -> a
 lgamma1_15G zm1 zm2 =
   r * y
     + r
@@ -62,7 +62,7 @@
     r = zm1 * zm2
     y = 0.52815341949462890625
 
-tableLogGamma_1_15PG :: RealFloat a => VB.Vector a
+tableLogGamma_1_15PG :: (RealFloat a) => VB.Vector a
 tableLogGamma_1_15PG =
   VB.fromList
     [ 0.490622454069039543534e-1,
@@ -75,7 +75,7 @@
     ]
 {-# NOINLINE tableLogGamma_1_15PG #-}
 
-tableLogGamma_1_15QG :: RealFloat a => VB.Vector a
+tableLogGamma_1_15QG :: (RealFloat a) => VB.Vector a
 tableLogGamma_1_15QG =
   VB.fromList
     [ 1,
@@ -88,7 +88,7 @@
     ]
 {-# NOINLINE tableLogGamma_1_15QG #-}
 
-lgamma15_2G :: RealFloat a => a -> a -> a
+lgamma15_2G :: (RealFloat a) => a -> a -> a
 lgamma15_2G zm1 zm2 =
   r * y
     + r
@@ -99,7 +99,7 @@
     r = zm1 * zm2
     y = 0.452017307281494140625
 
-tableLogGamma_15_2PG :: RealFloat a => VB.Vector a
+tableLogGamma_15_2PG :: (RealFloat a) => VB.Vector a
 tableLogGamma_15_2PG =
   VB.fromList
     [ -0.292329721830270012337e-1,
@@ -111,7 +111,7 @@
     ]
 {-# NOINLINE tableLogGamma_15_2PG #-}
 
-tableLogGamma_15_2QG :: RealFloat a => VB.Vector a
+tableLogGamma_15_2QG :: (RealFloat a) => VB.Vector a
 tableLogGamma_15_2QG =
   VB.fromList
     [ 1,
@@ -124,7 +124,7 @@
     ]
 {-# NOINLINE tableLogGamma_15_2QG #-}
 
-lgammaSmallG :: RealFloat a => a -> a
+lgammaSmallG :: (RealFloat a) => a -> a
 lgammaSmallG = go 0
   where
     go acc z
@@ -133,7 +133,7 @@
       where
         zm1 = z - 1
 
-lgamma2_3G :: RealFloat a => a -> a
+lgamma2_3G :: (RealFloat a) => a -> a
 lgamma2_3G z =
   r * y
     + r
@@ -145,7 +145,7 @@
     zm2 = z - 2
     y = 0.158963680267333984375e0
 
-tableLogGamma_2_3PG :: RealFloat a => VB.Vector a
+tableLogGamma_2_3PG :: (RealFloat a) => VB.Vector a
 tableLogGamma_2_3PG =
   VB.fromList
     [ -0.180355685678449379109e-1,
@@ -158,7 +158,7 @@
     ]
 {-# NOINLINE tableLogGamma_2_3PG #-}
 
-tableLogGamma_2_3QG :: RealFloat a => VB.Vector a
+tableLogGamma_2_3QG :: (RealFloat a) => VB.Vector a
 tableLogGamma_2_3QG =
   VB.fromList
     [ 1,
@@ -172,14 +172,14 @@
     ]
 {-# NOINLINE tableLogGamma_2_3QG #-}
 
-lanczosApproxG :: RealFloat a => a -> a
+lanczosApproxG :: (RealFloat a) => a -> a
 lanczosApproxG z =
   (log (z + g - 0.5) - 1) * (z - 0.5)
     + log (evalRatioG tableLanczosG z)
   where
     g = 6.024680040776729583740234375
 
-tableLanczosG :: RealFloat a => VB.Vector (a, a)
+tableLanczosG :: (RealFloat a) => VB.Vector (a, a)
 tableLanczosG =
   VB.fromList
     [ (56906521.91347156388090791033559122686859, 0),
@@ -200,7 +200,7 @@
 
 data LG a = LG !a !a
 
-evalRatioG :: RealFloat a => VB.Vector (a, a) -> a -> a
+evalRatioG :: (RealFloat a) => VB.Vector (a, a) -> a -> a
 evalRatioG coef x
   | x > 1 = fini $ VB.foldl' stepL (LG 0 0) coef
   | otherwise = fini $ VB.foldr' stepR (LG 0 0) coef
@@ -228,13 +228,13 @@
     stirling = (x - 0.5) * log x - x + mLnSqrt2Pi
     x = fromIntegral n + 1
     rx = recip x
-{-# SPECIALIZE logFactorialNonDouble :: RealFloat a => Int -> a #-}
+{-# SPECIALIZE logFactorialNonDouble :: (RealFloat a) => Int -> a #-}
 
-mLnSqrt2Pi :: RealFloat a => a
+mLnSqrt2Pi :: (RealFloat a) => a
 mLnSqrt2Pi = 0.9189385332046727417803297364056176398613974736377834128171
 {-# INLINE mLnSqrt2Pi #-}
 
-factorialTable :: RealFloat a => VB.Vector a
+factorialTable :: (RealFloat a) => VB.Vector a
 {-# NOINLINE factorialTable #-}
 factorialTable =
   VB.fromListN
diff --git a/src/Mcmc/Likelihood.hs b/src/Mcmc/Likelihood.hs
--- a/src/Mcmc/Likelihood.hs
+++ b/src/Mcmc/Likelihood.hs
@@ -29,6 +29,6 @@
 type LikelihoodFunctionG a b = a -> Log b
 
 -- | Flat likelihood function. Useful for testing and debugging.
-noLikelihood :: RealFloat b => LikelihoodFunctionG a b
+noLikelihood :: (RealFloat b) => LikelihoodFunctionG a b
 noLikelihood = const 1.0
 {-# SPECIALIZE noLikelihood :: LikelihoodFunction Double #-}
diff --git a/src/Mcmc/Logger.hs b/src/Mcmc/Logger.hs
--- a/src/Mcmc/Logger.hs
+++ b/src/Mcmc/Logger.hs
@@ -88,7 +88,7 @@
 msgPrepare pref msg = BL.intercalate "\n" $ map (BL.append pref) $ BL.lines msg
 
 -- Make sure that concurrent output is not scrambled.
-atomicAction :: HasLock e => IO () -> Logger e ()
+atomicAction :: (HasLock e) => IO () -> Logger e ()
 atomicAction a = do
   l <- reader getLock
   liftIO $ withMVar l (const a)
diff --git a/src/Mcmc/MarginalLikelihood.hs b/src/Mcmc/MarginalLikelihood.hs
--- a/src/Mcmc/MarginalLikelihood.hs
+++ b/src/Mcmc/MarginalLikelihood.hs
@@ -141,7 +141,7 @@
     f j = fromIntegral j / fromIntegral k1
 
 sampleAtPoint ::
-  ToJSON a =>
+  (ToJSON a) =>
   Bool ->
   Point ->
   Settings ->
@@ -187,7 +187,7 @@
     a' = MHG ch'
 
 traversePoints ::
-  ToJSON a =>
+  (ToJSON a) =>
   NPoints ->
   [(Int, Point)] ->
   Settings ->
@@ -237,7 +237,7 @@
 chop _ _ = error "chop: not all list elements handled"
 
 mlRunPar ::
-  ToJSON a =>
+  (ToJSON a) =>
   ParallelizationMode ->
   NPoints ->
   [(Int, Point)] ->
@@ -269,7 +269,7 @@
   pure $ concat xss
 
 mlRun ::
-  ToJSON a =>
+  (ToJSON a) =>
   NPoints ->
   [(Int, Point)] ->
   ExecutionMode ->
@@ -320,7 +320,7 @@
     go _ _ = 0
 
 tiWrapper ::
-  ToJSON a =>
+  (ToJSON a) =>
   MLSettings ->
   PriorFunction a ->
   LikelihoodFunction a ->
@@ -404,7 +404,7 @@
 --                 llhsNormed = VU.map (\x -> x - llhMax) llhs
 --                 lhsNormedPowered = VU.map (\x -> exp $ dbeta * x) llhsNormed
 sssWrapper ::
-  ToJSON a =>
+  (ToJSON a) =>
   MLSettings ->
   PriorFunction a ->
   LikelihoodFunction a ->
@@ -429,7 +429,7 @@
 
 -- | Estimate the marginal likelihood.
 marginalLikelihood ::
-  ToJSON a =>
+  (ToJSON a) =>
   MLSettings ->
   PriorFunction a ->
   LikelihoodFunction a ->
diff --git a/src/Mcmc/Mcmc.hs b/src/Mcmc/Mcmc.hs
--- a/src/Mcmc/Mcmc.hs
+++ b/src/Mcmc/Mcmc.hs
@@ -40,7 +40,7 @@
 -- transforming the state @a@.
 type MCMC = ReaderT (Environment Settings) IO
 
-mcmcExecute :: Algorithm a => a -> MCMC a
+mcmcExecute :: (Algorithm a) => a -> MCMC a
 mcmcExecute a = do
   logDebugB "Executing MCMC run."
   s <- reader settings
@@ -51,12 +51,12 @@
   logDebugB "Executed MCMC run."
   return a'
 
-mcmcResetAcceptance :: Algorithm a => a -> MCMC a
+mcmcResetAcceptance :: (Algorithm a) => a -> MCMC a
 mcmcResetAcceptance a = do
   logDebugB "Reset acceptance rates."
   return $ aResetAcceptance ResetEverything a
 
-mcmcExceptionHandler :: Algorithm a => Environment Settings -> a -> AsyncException -> IO b
+mcmcExceptionHandler :: (Algorithm a) => Environment Settings -> a -> AsyncException -> IO b
 mcmcExceptionHandler e a err = do
   _ <- runReaderT action e
   putStrLn "Graceful termination successful."
@@ -69,7 +69,7 @@
       logWarnS "Press CTRL-C (again) to terminate now."
       mcmcClose a
 
-mcmcExecuteMonitors :: Algorithm a => a -> MCMC ()
+mcmcExecuteMonitors :: (Algorithm a) => a -> MCMC ()
 mcmcExecuteMonitors a = do
   e <- ask
   let s = settings e
@@ -87,46 +87,46 @@
   | IntermediateTuningOff
   deriving (Eq)
 
-mcmcIterate :: Algorithm a => IntermediateTuningSpec -> IterationMode -> Int -> a -> MCMC a
-mcmcIterate t m n a
-  | n < 0 = error "mcmcIterate: Number of iterations is negative."
-  | n == 0 = return a
-  | otherwise = do
-      e <- ask
-      let p = sParallelizationMode $ settings e
-      -- NOTE: Handle interrupts during iterations, before writing monitors,
-      -- using the old algorithm state @a@.
-      let handlerOld = mcmcExceptionHandler e a
-          maybeIntermediateAutoTune x =
-            -- Do not perform intermediate tuning at the last step, because a
-            -- normal tuning will be performed.
-            case t of
-              IntermediateTuningFastProposalsOnlyOn
-                | n > 1 ->
-                    aAutoTune IntermediateTuningFastProposalsOnly 1 x
-                      <&> aResetAcceptance ResetExpectedRatesOnly
-              IntermediateTuningAllProposalsOn
-                | n > 1 ->
-                    aAutoTune IntermediateTuningAllProposals 1 x
-                      <&> aResetAcceptance ResetExpectedRatesOnly
-              _ -> pure x
-          actionIterate = aIterate m p a >>= maybeIntermediateAutoTune
-      a' <- liftIO $ actionIterate `catch` handlerOld
-      -- NOTE: Mask asynchronous exceptions while writing monitor files. Handle
-      -- interrupts after writing monitors; use the new state @a'@.
-      --
-      -- The problem that arises using this method is: What if executing the
-      -- monitors actually throws an error (and not the user or the operating
-      -- system that want to stop the chain). In this case, the chain is left in
-      -- an undefined state because the monitor files are partly written; the
-      -- new state is saved by the handler. However, I do not think I can
-      -- recover from partly written monitor files.
-      let handlerNew = mcmcExceptionHandler e a'
-          actionWrite = runReaderT (mcmcExecuteMonitors a') e
-      liftIO $ uninterruptibleMask_ actionWrite `catch` handlerNew
-      mcmcIterate t m (n - 1) a'
+mcmcIterate :: (Algorithm a) => IntermediateTuningSpec -> IterationMode -> Int -> a -> MCMC a
+mcmcIterate t m n a = case n `compare` 0 of
+  LT -> error "mcmcIterate: Number of iterations is negative."
+  EQ -> return a
+  GT -> do
+    e <- ask
+    let p = sParallelizationMode $ settings e
+    -- NOTE: Handle interrupts during iterations, before writing monitors,
+    -- using the old algorithm state @a@.
+    let handlerOld = mcmcExceptionHandler e a
+        maybeIntermediateAutoTune x =
+          -- Do not perform intermediate tuning at the last step, because a
+          -- normal tuning will be performed.
+          case t of
+            IntermediateTuningFastProposalsOnlyOn
+              | n > 1 ->
+                  aAutoTune IntermediateTuningFastProposalsOnly 1 x
+                    <&> aResetAcceptance ResetExpectedRatesOnly
+            IntermediateTuningAllProposalsOn
+              | n > 1 ->
+                  aAutoTune IntermediateTuningAllProposals 1 x
+                    <&> aResetAcceptance ResetExpectedRatesOnly
+            _otherTuningSpecs -> pure x
+        actionIterate = aIterate m p a >>= maybeIntermediateAutoTune
+    a' <- liftIO $ actionIterate `catch` handlerOld
+    -- NOTE: Mask asynchronous exceptions while writing monitor files. Handle
+    -- interrupts after writing monitors; use the new state @a'@.
+    --
+    -- The problem that arises using this method is: What if executing the
+    -- monitors actually throws an error (and not the user or the operating
+    -- system that want to stop the chain). In this case, the chain is left in
+    -- an undefined state because the monitor files are partly written; the
+    -- new state is saved by the handler. However, I do not think I can
+    -- recover from partly written monitor files.
+    let handlerNew = mcmcExceptionHandler e a'
+        actionWrite = runReaderT (mcmcExecuteMonitors a') e
+    liftIO $ uninterruptibleMask_ actionWrite `catch` handlerNew
+    mcmcIterate t m (n - 1) a'
 
-mcmcNewRun :: Algorithm a => a -> MCMC a
+mcmcNewRun :: (Algorithm a) => a -> MCMC a
 mcmcNewRun a = do
   s <- reader settings
   logInfoB "Starting new MCMC sampler."
@@ -145,7 +145,7 @@
   logInfoB $ aStdMonitorHeader a''
   mcmcIterate IntermediateTuningOff AllProposals i a''
 
-mcmcContinueRun :: Algorithm a => a -> MCMC a
+mcmcContinueRun :: (Algorithm a) => a -> MCMC a
 mcmcContinueRun a = do
   s <- reader settings
   let iBurnIn = burnInIterations (sBurnIn s)
@@ -164,7 +164,7 @@
   logInfoB $ aStdMonitorHeader a
   mcmcIterate IntermediateTuningOff AllProposals di a
 
-mcmcBurnIn :: Algorithm a => a -> MCMC a
+mcmcBurnIn :: (Algorithm a) => a -> MCMC a
 mcmcBurnIn a = do
   s <- reader settings
   case sBurnIn s of
@@ -213,7 +213,7 @@
       return a''
 
 -- Auto tune the proposals.
-mcmcAutotune :: Algorithm a => TuningType -> Int -> a -> MCMC a
+mcmcAutotune :: (Algorithm a) => TuningType -> Int -> a -> MCMC a
 mcmcAutotune t n a = do
   case t of
     NormalTuningFastProposalsOnly -> logDebugB "Normal auto tune; fast proposals only."
@@ -224,7 +224,7 @@
     LastTuningAllProposals -> logDebugB "Last auto tune; all proposals."
   liftIO $ aAutoTune t n a
 
-mcmcBurnInWithAutoTuning :: Algorithm a => IterationMode -> [Int] -> a -> MCMC a
+mcmcBurnInWithAutoTuning :: (Algorithm a) => IterationMode -> [Int] -> a -> MCMC a
 mcmcBurnInWithAutoTuning _ [] _ = error "mcmcBurnInWithAutoTuning: Empty list."
 mcmcBurnInWithAutoTuning m [x] a = do
   -- Last round.
@@ -248,7 +248,7 @@
   a''' <- mcmcResetAcceptance a''
   mcmcBurnInWithAutoTuning m xs a'''
 
-mcmcInitialize :: Algorithm a => a -> MCMC a
+mcmcInitialize :: (Algorithm a) => a -> MCMC a
 mcmcInitialize a = do
   logInfoS $ aName a ++ " algorithm."
   s <- settings <$> ask
@@ -258,7 +258,7 @@
   return a'
 
 -- Save the MCMC run.
-mcmcSave :: Algorithm a => a -> MCMC ()
+mcmcSave :: (Algorithm a) => a -> MCMC ()
 mcmcSave a = do
   s <- reader settings
   case sSaveMode s of
@@ -273,7 +273,7 @@
       logInfoB "Markov chain saved. Analysis can be continued."
 
 -- Report and finish up.
-mcmcClose :: Algorithm a => a -> MCMC a
+mcmcClose :: (Algorithm a) => a -> MCMC a
 mcmcClose a = do
   logInfoS "Closing monitors."
   a' <- liftIO $ aCloseMonitors a
@@ -285,7 +285,7 @@
   return a'
 
 -- Initialize the run, execute the run, and close the run.
-mcmcRun :: Algorithm a => a -> MCMC a
+mcmcRun :: (Algorithm a) => a -> MCMC a
 mcmcRun a = do
   -- Header.
   logInfoHeader
@@ -304,7 +304,7 @@
   mcmcClose a''
 
 -- | Run an MCMC algorithm with given settings.
-mcmc :: Algorithm a => Settings -> a -> IO a
+mcmc :: (Algorithm a) => Settings -> a -> IO a
 mcmc s a = do
   settingsCheck s $ aIteration a
   e <- initializeEnvironment s
@@ -322,7 +322,7 @@
 -- - 'Mcmc.Algorithm.MHG.mhgLoad'
 --
 -- - 'Mcmc.Algorithm.MC3.mc3Load'
-mcmcContinue :: Algorithm a => Iterations -> Settings -> a -> IO a
+mcmcContinue :: (Algorithm a) => Iterations -> Settings -> a -> IO a
 mcmcContinue dn s = mcmc s'
   where
     n' = Iterations $ fromIterations (sIterations s) + fromIterations dn
diff --git a/src/Mcmc/Monitor/ParameterBatch.hs b/src/Mcmc/Monitor/ParameterBatch.hs
--- a/src/Mcmc/Monitor/ParameterBatch.hs
+++ b/src/Mcmc/Monitor/ParameterBatch.hs
@@ -55,7 +55,7 @@
 instance Contravariant MonitorParameterBatch where
   contramap f (MonitorParameterBatch n m) = MonitorParameterBatch n (m . VB.map f)
 
-mean :: Real a => VB.Vector a -> Double
+mean :: (Real a) => VB.Vector a -> Double
 mean xs = realToFrac (VB.sum xs) / fromIntegral (VB.length xs)
 {-# SPECIALIZE mean :: VB.Vector Double -> Double #-}
 {-# SPECIALIZE mean :: VB.Vector Int -> Double #-}
@@ -64,7 +64,7 @@
 --
 -- Print the mean with eight decimal places (half precision).
 monitorBatchMean ::
-  Real a =>
+  (Real a) =>
   -- | Name.
   String ->
   MonitorParameterBatch a
@@ -76,7 +76,7 @@
 --
 -- Print the mean with full precision.
 monitorBatchMeanF ::
-  Real a =>
+  (Real a) =>
   -- | Name.
   String ->
   MonitorParameterBatch a
@@ -88,7 +88,7 @@
 --
 -- Print the real float parameters such as 'Double' with scientific notation.
 monitorBatchMeanS ::
-  Real a =>
+  (Real a) =>
   -- | Name.
   String ->
   MonitorParameterBatch a
diff --git a/src/Mcmc/Monitor/Time.hs b/src/Mcmc/Monitor/Time.hs
--- a/src/Mcmc/Monitor/Time.hs
+++ b/src/Mcmc/Monitor/Time.hs
@@ -46,5 +46,5 @@
     ts = round dt
 
 -- | Render a time stamp.
-renderTime :: FormatTime t => t -> String
+renderTime :: (FormatTime t) => t -> String
 renderTime = formatTime defaultTimeLocale "%B %-e, %Y, at %H:%M %P, %Z."
diff --git a/src/Mcmc/Prior.hs b/src/Mcmc/Prior.hs
--- a/src/Mcmc/Prior.hs
+++ b/src/Mcmc/Prior.hs
@@ -59,38 +59,38 @@
 type PriorFunctionG a b = a -> Log b
 
 -- | Flat prior function. Useful for testing and debugging.
-noPrior :: RealFloat b => PriorFunctionG a b
+noPrior :: (RealFloat b) => PriorFunctionG a b
 noPrior = const 1.0
 {-# SPECIALIZE noPrior :: PriorFunction Double #-}
 
 -- | Improper uniform prior; strictly greater than a given value.
-greaterThan :: RealFloat a => LowerBoundary a -> PriorFunctionG a a
+greaterThan :: (RealFloat a) => LowerBoundary a -> PriorFunctionG a a
 greaterThan a x
   | x > a = 1.0
   | otherwise = 0.0
 {-# SPECIALIZE greaterThan :: Double -> PriorFunction Double #-}
 
 -- | Improper uniform prior; strictly greater than zero.
-positive :: RealFloat a => PriorFunctionG a a
+positive :: (RealFloat a) => PriorFunctionG a a
 positive = greaterThan 0
 {-# SPECIALIZE positive :: PriorFunction Double #-}
 
 -- | Improper uniform prior; strictly less than a given value.
-lessThan :: RealFloat a => UpperBoundary a -> PriorFunctionG a a
+lessThan :: (RealFloat a) => UpperBoundary a -> PriorFunctionG a a
 lessThan a x
   | x < a = 1.0
   | otherwise = 0.0
 {-# SPECIALIZE lessThan :: Double -> PriorFunction Double #-}
 
 -- | Improper uniform prior; strictly less than zero.
-negative :: RealFloat a => PriorFunctionG a a
+negative :: (RealFloat a) => PriorFunctionG a a
 negative = lessThan 0.0
 {-# SPECIALIZE negative :: PriorFunction Double #-}
 
 -- | Exponential distributed prior.
 --
 -- Call 'error' if the rate is zero or negative.
-exponential :: RealFloat a => Rate a -> PriorFunctionG a a
+exponential :: (RealFloat a) => Rate a -> PriorFunctionG a a
 exponential l x
   | l <= 0.0 = error "exponential: Rate is zero or negative."
   | x <= 0.0 = 0.0
@@ -136,17 +136,17 @@
 
 -- | Calculate mean and variance of the gamma distribution given the shape and
 -- the scale.
-gammaShapeScaleToMeanVariance :: Num a => Shape a -> Scale a -> (Mean a, Variance a)
+gammaShapeScaleToMeanVariance :: (Num a) => Shape a -> Scale a -> (Mean a, Variance a)
 gammaShapeScaleToMeanVariance k t = let m = k * t in (m, m * t)
 {-# SPECIALIZE gammaShapeScaleToMeanVariance :: Double -> Double -> (Double, Double) #-}
 
 -- | Calculate shape and scale of the gamma distribution given the mean and
 -- the variance.
-gammaMeanVarianceToShapeScale :: Fractional a => Mean a -> Variance a -> (Shape a, Scale a)
+gammaMeanVarianceToShapeScale :: (Fractional a) => Mean a -> Variance a -> (Shape a, Scale a)
 gammaMeanVarianceToShapeScale m v = (m * m / v, v / m)
 {-# SPECIALIZE gammaMeanVarianceToShapeScale :: Double -> Double -> (Double, Double) #-}
 
-mLnSqrt2Pi :: RealFloat a => a
+mLnSqrt2Pi :: (RealFloat a) => a
 mLnSqrt2Pi = 0.9189385332046727417803297364056176398613974736377834128171
 {-# INLINE mLnSqrt2Pi #-}
 
@@ -158,7 +158,7 @@
 -- \(\mu\) and \(\sigma\), but are not the same as \(\mu\) and \(\sigma\)!
 --
 -- Call 'error' if the standard deviation is zero or negative.
-logNormal :: RealFloat a => Mean a -> StandardDeviation a -> PriorFunctionG a a
+logNormal :: (RealFloat a) => Mean a -> StandardDeviation a -> PriorFunctionG a a
 logNormal m s x
   | s <= 0.0 = error "logNormal: Standard deviation is zero or negative."
   | x <= 0.0 = 0.0
@@ -172,7 +172,7 @@
 -- | Normal distributed prior.
 --
 -- Call 'error' if the standard deviation is zero or negative.
-normal :: RealFloat a => Mean a -> StandardDeviation a -> PriorFunctionG a a
+normal :: (RealFloat a) => Mean a -> StandardDeviation a -> PriorFunctionG a a
 normal m s x
   | s <= 0 = error "normal: Standard deviation is zero or negative."
   | otherwise = Exp $ (-xm * xm / (2 * s * s)) - denom
@@ -184,7 +184,7 @@
 -- | Uniform prior on [a, b].
 --
 -- Call 'error' if the lower boundary is greather than the upper boundary.
-uniform :: RealFloat a => LowerBoundary a -> UpperBoundary a -> PriorFunctionG a a
+uniform :: (RealFloat a) => LowerBoundary a -> UpperBoundary a -> PriorFunctionG a a
 uniform a b x
   | a > b = error "uniform: Lower boundary is greater than upper boundary."
   | x < a = 0.0
@@ -205,11 +205,11 @@
 --
 -- Use with care because the elements are checked for positiveness, and this can
 -- take some time if the list is long and does not contain any zeroes.
-product' :: RealFloat a => [Log a] -> Log a
+product' :: (RealFloat a) => [Log a] -> Log a
 product' = fromMaybe 0 . prodM
 {-# SPECIALIZE product' :: [Log Double] -> Log Double #-}
 
 -- The type could be generalized to any MonadPlus Integer
-prodM :: RealFloat a => [Log a] -> Maybe (Log a)
+prodM :: (RealFloat a) => [Log a] -> Maybe (Log a)
 prodM = foldM (\ !acc x -> (acc * x) <$ guard (acc /= 0.0)) 1.0
 {-# SPECIALIZE prodM :: [Log Double] -> Maybe (Log Double) #-}
diff --git a/src/Mcmc/Proposal/Hamiltonian/Hamiltonian.hs b/src/Mcmc/Proposal/Hamiltonian/Hamiltonian.hs
--- a/src/Mcmc/Proposal/Hamiltonian/Hamiltonian.hs
+++ b/src/Mcmc/Proposal/Hamiltonian/Hamiltonian.hs
@@ -97,7 +97,7 @@
 defaultHParams = HParams Nothing Nothing Nothing
 
 hamiltonianPFunctionWithTuningParameters ::
-  Traversable s =>
+  (Traversable s) =>
   Dimension ->
   HStructure s ->
   (s Double -> Target) ->
@@ -159,7 +159,7 @@
 --
 -- May call 'error' during initialization.
 hamiltonian ::
-  Traversable s =>
+  (Traversable s) =>
   HParams ->
   HTuningConf ->
   HStructure s ->
diff --git a/src/Mcmc/Proposal/Hamiltonian/Internal.hs b/src/Mcmc/Proposal/Hamiltonian/Internal.hs
--- a/src/Mcmc/Proposal/Hamiltonian/Internal.hs
+++ b/src/Mcmc/Proposal/Hamiltonian/Internal.hs
@@ -235,7 +235,7 @@
 
 -- See Algorithm 4 in [4].
 findReasonableEpsilon ::
-  StatefulGen g m =>
+  (StatefulGen g m) =>
   Target ->
   Masses ->
   Positions ->
@@ -325,7 +325,7 @@
   where
     err msg = error $ "hTuningFunctionWith: " <> msg
 
-checkHStructureWith :: Foldable s => Masses -> HStructure s -> Maybe String
+checkHStructureWith :: (Foldable s) => Masses -> HStructure s -> Maybe String
 checkHStructureWith ms (HStructure x toVec fromVec)
   | toList (fromVec x xVec) /= toList x = eWith "'fromVectorWith x (toVector x) /= x' for sample state."
   | L.size xVec /= nrows = eWith "Mass matrix and 'toVector x' have different sizes for sample state."
@@ -337,7 +337,7 @@
 
 -- Generate momenta for a new iteration.
 generateMomenta ::
-  StatefulGen g m =>
+  (StatefulGen g m) =>
   Mu ->
   Masses ->
   g ->
diff --git a/src/Mcmc/Proposal/Hamiltonian/Nuts.hs b/src/Mcmc/Proposal/Hamiltonian/Nuts.hs
--- a/src/Mcmc/Proposal/Hamiltonian/Nuts.hs
+++ b/src/Mcmc/Proposal/Hamiltonian/Nuts.hs
@@ -171,7 +171,7 @@
 defaultNParams = NParams Nothing Nothing
 
 nutsPFunctionWithTuningParameters ::
-  Traversable s =>
+  (Traversable s) =>
   Dimension ->
   HStructure s ->
   (s Double -> Target) ->
@@ -264,7 +264,7 @@
 --
 -- May call 'error' during initialization.
 nuts ::
-  Traversable s =>
+  (Traversable s) =>
   NParams ->
   HTuningConf ->
   HStructure s ->