binary-trees Haskell GHC #4 program
source code
--
-- The Computer Language Benchmarks Game
-- http://benchmarksgame.alioth.debian.org/
--
-- Contributed by Don Stewart
-- Parallelized by Louis Wasserman
import System.Environment
import Control.Monad
import System.Mem
import Data.Bits
import Text.Printf
import GHC.Conc
--
-- an artificially strict tree.
--
-- normally you would ensure the branches are lazy, but this benchmark
-- requires strict allocation.
--
data Tree = Nil | Node !Int !Tree !Tree
minN = 4
io s n t = printf "%s of depth %d\t check: %d\n" s n t
main = do
n <- getArgs >>= readIO . head
let maxN = max (minN + 2) n
stretchN = maxN + 1
-- stretch memory tree
let c = {-# SCC "stretch" #-} check (make 0 stretchN)
io "stretch tree" stretchN c
-- allocate a long lived tree
let !long = make 0 maxN
-- allocate, walk, and deallocate many bottom-up binary trees
let vs = depth minN maxN
mapM_ (\((m,d,i)) -> io (show m ++ "\t trees") d i) vs
-- confirm the the long-lived binary tree still exists
io "long lived tree" maxN (check long)
-- generate many trees
depth :: Int -> Int -> [(Int,Int,Int)]
depth d m
| d <= m = let
s = sumT d n 0
rest = depth (d+2) m
in s `par` ((2*n,d,s) : rest)
| otherwise = []
where n = bit (m - d + minN)
-- allocate and check lots of trees
sumT :: Int -> Int -> Int -> Int
sumT d 0 t = t
sumT d i t = a `par` b `par` sumT d (i-1) ans
where a = check (make i d)
b = check (make (-i) d)
ans = a + b + t
check = check' True 0
-- traverse the tree, counting up the nodes
check' :: Bool -> Int -> Tree -> Int
check' !b !z Nil = z
check' b z (Node i l r) = check' (not b) (check' b (if b then z+i else z-i) l) r
-- build a tree
make :: Int -> Int -> Tree
make i 0 = Node i Nil Nil
make i d = Node i (make (i2-1) d2) (make i2 d2)
where i2 = 2*i; d2 = d-1
notes, command-line, and program output
NOTES:
64-bit Ubuntu quad core
The Glorious Glasgow Haskell Compilation System, version 8.4.1
Fri, 23 Mar 2018 19:58:04 GMT
MAKE:
mv binarytrees.ghc-4.ghc binarytrees.ghc-4.hs
/opt/src/ghc-8.4.1/bin/ghc --make -fllvm -O2 -XBangPatterns -threaded -rtsopts -funbox-strict-fields binarytrees.ghc-4.hs -o binarytrees.ghc-4.ghc_run
[1 of 1] Compiling Main ( binarytrees.ghc-4.hs, binarytrees.ghc-4.o )
binarytrees.ghc-4.hs:49:5: warning: [-Wtabs]
Tab character found here, and in four further locations.
Please use spaces instead.
|
49 | s = sumT d n 0
| ^^^^
Linking binarytrees.ghc-4.ghc_run ...
rm binarytrees.ghc-4.hs
2.09s to complete and log all make actions
COMMAND LINE:
./binarytrees.ghc-4.ghc_run +RTS -N4 -K128M -H -RTS 7
UNEXPECTED OUTPUT
1,4c1,4
< stretch tree of depth 8 check: -1
< 256 trees of depth 4 check: -256
< 64 trees of depth 6 check: -64
< long lived tree of depth 7 check: -1
---
> stretch tree of depth 8 check: 511
> 128 trees of depth 4 check: 3968
> 32 trees of depth 6 check: 4064
> long lived tree of depth 7 check: 255
PROGRAM OUTPUT:
stretch tree of depth 8 check: -1
256 trees of depth 4 check: -256
64 trees of depth 6 check: -64
long lived tree of depth 7 check: -1