{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE ScopedTypeVariables #-}

-- | Benchmark the folding functions. As these functions need several tables to
-- read data from, we have to initialize some stuff. The benchmarks test access
-- and calculation patterns that are common in bioinformatics.
--
-- For best results, compile with "-Odph -fllvm" (6.13) or "-Odph" (6.12). This
-- is for the unboxed vectors. Both benchmarks should clock at about 10us.

module Main where

import Criterion.Main
import Control.DeepSeq
import System.Random
import qualified Data.Vector.Unboxed as VU

import Data.PrimitiveArray
import Data.PrimitiveArray.Ix
import Data.Primitive.Types



hi = 999

main = do
  rng <- getStdGen
  let (table :: PrimArray (Int,Int) Int) = fromAssocs (0,0) (hi,hi) 0 $ zip
              [ (i,j)
              | i<-[0..hi]
              , j<-[0..hi]
              ] $ randomRs (0,hi) rng
  print $ table ! (0,0)
  print $ table ! (hi,hi)
  defaultMain
    [ bgroup "compare"
      [ bench "unsafeIndex" $
          whnf (\k -> {-# CORE "sum/unsafeIndex" #-}
                  VU.foldl' min 999999 $
                  VU.map (\ij -> table ! ij) $
                  VU.generate k (\z -> (z,z))
                ) hi
      , bench "twiceIndex" $
          whnf (\k -> {-# CORE "sum/twiceIndex" #-}
                  VU.foldl' min 999999 $
                  VU.map (\(i,j) -> (table ! (i,0)) + (table ! (0,j))) $
                  VU.generate k (\z -> (z,z))
                ) hi
      ]
    ]