flat-mcmc

commit 9622e0ae714ed09ef5e3352010104999c1799fc8
parent 1b35e1cc34c41d93b11a887e37279622aade0e05
Author: Jared Tobin <jared@jtobin.ca>
Date:   Mon,  5 Nov 2012 13:27:38 +1300

Serialize to float rather than double.

Diffstat:
M
Examples/code/SPDE_Flat.hs
 | 
6
++++--
M
Numeric/MCMC/Flat.hs
 | 
3
++-

2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/Examples/code/SPDE_Flat.hs b/Examples/code/SPDE_Flat.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE BangPatterns #-}
+
 import System.IO
 import System.Exit
 import System.Environment
@@ -8,8 +10,8 @@ import qualified Data.Vector as V
 
 target :: [Double] -> Double
 target xs = go 0 0 xs 
-  where go t0 t1 []         = (- t0 / (2*h)) - (0.5 * h * t1)
-        go t0 t1 (u:us:uss) = go (t0 + (us - u)^2) (t1 + v (us + u)) uss
+  where go !t0 !t1 []         = (-t0 / (2*h)) - (0.5*h*t1)
+        go !t0 !t1 (u:us:uss) = go (t0 + (us - u)^2) (t1 + v (us + u)) uss
         h   = 1 / fromIntegral (length xs)
         v x = (1 - x^2)^2
 {-# INLINE target #-}
diff --git a/Numeric/MCMC/Flat.hs b/Numeric/MCMC/Flat.hs
@@ -16,6 +16,7 @@ import qualified Data.Vector.Unboxed   as U
 import Control.Monad.Par                    (NFData)
 import Control.Monad.Par.Scheds.Direct
 import Control.Monad.Par.Combinator
+import GHC.Float
 import System.IO
 
 -- | Parallel map with a specified granularity.
@@ -34,7 +35,7 @@ data MarkovChain = MarkovChain { ensemble :: Ensemble
 
 -- | Display the current state.  This will be very slow and should be replaced.
 instance Show MarkovChain where
-    show config = filter (`notElem` "[]") $ unlines $ map show (V.toList (ensemble config))
+    show config = filter (`notElem` "[]") $ unlines $ map (show . map double2Float) (V.toList (ensemble config))
 
 -- | Options for the chain.  The target (expected to be a log density), as
 --   well as the size of the ensemble.  The size should be an even number.  Also