safe wrappers and examples/parallel.hs

1 files changed, 18 insertions, 10 deletions

diff --git a/examples/experiments/parallel.hs b/examples/experiments/parallel.hs
index 7256fb6..dfbfd88 100644
--- a/examples/experiments/parallel.hs
+++ b/examples/experiments/parallel.hs
@@ -5,24 +5,32 @@ import System.Time
 
 inParallel = parMap rwhnf id
 
-parMul x y = fromBlocks [inParallel[x <> y1, x <> y2]]
-    where p = cols y `div` 2
-          (y1,y2) = splitColumnsAt p y
+parMul p x y = fromBlocks [ inParallel ( map (x <>) ys ) ]
+    where ys = splitColumns p y
+
 
 main = do
     n <- (read . head) `fmap` getArgs
     let m = ident n :: Matrix Double
-    time $ print $ vectorMax $ takeDiag $ parMul m m
     time $ print $ vectorMax $ takeDiag $ m <> m
-
-a = (2><3) [1..6::Double]
-b = (3><4) [1..12::Double]
-
-splitRowsAt p m    = (takeRows p m, dropRows p m)
-splitColumnsAt p m = (takeColumns p m, dropColumns p m)
+    time $ print $ vectorMax $ takeDiag $ parMul 2 m m
+    time $ print $ vectorMax $ takeDiag $ parMul 4 m m
+    time $ print $ vectorMax $ takeDiag $ parMul 8 m m
 
 time act = do
     t0 <- getClockTime
     act
     t1 <- getClockTime
     print $ tdSec $ normalizeTimeDiff $ diffClockTimes t1 t0
+
+splitColumns n m = splitColumns' (f n (cols m)) m
+    where
+    splitColumns' [] m = []
+    splitColumns' ((a,b):rest) m = subMatrix (0,a) (rows m, b-a+1) m : splitColumns' rest m
+
+    f :: Int -> Int -> [(Int,Int)]
+    f n c = zip ks (map pred $ tail ks)
+        where ks = map round $ toList $ linspace (fromIntegral n+1) (0,fromIntegral c)
+
+splitRowsAt p m    = (takeRows p m, dropRows p m)
+splitColumnsAt p m = (takeColumns p m, dropColumns p m)