added examples/benchmarks.hs

1 files changed, 44 insertions, 0 deletions

diff --git a/examples/benchmarks.hs b/examples/benchmarks.hs
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+{-# OPTIONS -fbang-patterns #-}
+
+-- compile as:
+-- ghc --make -O2 -optc-O2 -fvia-C  benchmarks.hs -o benchmarks
+
+import Numeric.LinearAlgebra
+import System.Time
+import System.CPUTime
+import Text.Printf
+
+
+time act = do
+    t0 <- getCPUTime
+    act
+    t1 <- getCPUTime
+    putStrLn $ show ((t1-t0) `div` 10^10) ++ " cs"
+
+time' act = do
+    t0 <- getClockTime
+    act
+    t1 <- getClockTime
+    putStrLn $ timeDiffToString $ normalizeTimeDiff $ diffClockTimes t1 t0
+
+--------------------------------------------------------------------------------
+
+main = sequence_ [bench1]
+
+bench1 = do
+    putStrLn "sum of a vector with 30 million doubles:"
+    time $ printf "     BLAS: %.2f: " $ sumV sumVB 30000000
+    time $ printf "  Haskell: %.2f: " $ sumV sumVH 30000000
+    time $ printf "     BLAS: %.2f: " $ sumV sumVB 30000000
+    time $ printf "  Haskell: %.2f: " $ sumV sumVH 30000000
+
+sumV f n = f (constant (1::Double) n)
+
+sumVB v = constant 1 (dim v) <.> v
+
+sumVH v = go (d - 1) 0
+     where
+       d = dim v
+       go :: Int -> Double -> Double
+       go 0 s = s + (v @> 0)
+       go !j !s = go (j - 1) (s + (v @> j))