From 1925c123d7d8184a1d2ddc0a413e0fd2776e1083 Mon Sep 17 00:00:00 2001
From: Alberto Ruiz <aruiz@um.es>
Date: Thu, 8 May 2014 08:48:12 +0200
Subject: empty hmatrix-base

---
 packages/hmatrix/examples/parallel.hs | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 packages/hmatrix/examples/parallel.hs

(limited to 'packages/hmatrix/examples/parallel.hs')

diff --git a/packages/hmatrix/examples/parallel.hs b/packages/hmatrix/examples/parallel.hs
new file mode 100644
index 0000000..e875407
--- /dev/null
+++ b/packages/hmatrix/examples/parallel.hs
@@ -0,0 +1,28 @@
+-- $ ghc --make -O -rtsopts -threaded parallel.hs
+-- $ ./parallel 3000 +RTS -N4 -s -A200M
+
+import System.Environment(getArgs)
+import Numeric.LinearAlgebra
+import Control.Parallel.Strategies
+import System.Time
+
+inParallel = parMap rwhnf id
+
+-- matrix product decomposed into p parallel subtasks
+parMul p x y = fromBlocks [ inParallel ( map (x <>) ys ) ]
+    where [ys] = toBlocksEvery (rows y) (cols y `div` p) y
+
+main = do
+    n <- (read . head) `fmap` getArgs
+    let m = ident n :: Matrix Double
+    time $ print $ maxElement $ takeDiag $ m <> m
+    time $ print $ maxElement $ takeDiag $ parMul 2 m m
+    time $ print $ maxElement $ takeDiag $ parMul 4 m m
+    time $ print $ maxElement $ takeDiag $ parMul 8 m m
+
+time act = do
+    t0 <- getClockTime
+    act
+    t1 <- getClockTime
+    print $ tdSec $ normalizeTimeDiff $ diffClockTimes t1 t0
+
-- 
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