Questions tagged [stream-fusion]
8 questions
44
votes
1 answer
What is fusion in Haskell?
Every now and again I have been noticing the following in Haskell documentation:
(for example in Data.Text):
Subject to fusion
What is fusion and how do I use it?
Abraham P
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11
votes
0 answers
Why does -O2 have such a big impact on a simple L1 distance calculator in Haskell?
I have implemented a simple L1 distance calculator using Haskell. Since I am interested in performance I used unboxed vectors to store the images to compare.
calculateL1Distance :: LabeledImage -> LabeledImage -> Int
calculateL1Distance reference…
Oliver Gerlach
- 373
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9
votes
2 answers
Why `Vector.length (Vector.replicate n 0)" is not fused?
The following code unexpectedly (at least for me) produces an intermediate vector:
import qualified Data.Vector as Vector
main :: IO ()
main =
print (test n)
n :: Int
n = 1000000
test :: Int -> Int
test n = Vector.length (Vector.replicate n (0…
Yuras
- 13,856
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6
votes
1 answer
How to create Haskell containers that fuse?
I'm interested in creating a new Haskell container type (strict lists), and I want to make sure that operations on them are eligible for stream fusion. How do I opt-in to ghc's stream fusion capability?
If my container is Traversable, will it fuse…
yong
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5
votes
1 answer
Ever increasing CPU consumption with Haskell and stream-fusion
Here is a short Haskell program that generates a 440 Hz sound. It uses pulseaudio as an audio backend.
import GHC.Float
import Control.Arrow
import Sound.Pulse.Simple
import qualified Data.List.Stream as S
import Data.List
type Time = Double
type…
netom
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1
vote
1 answer
How can I improve performance of this minmax implementation?
Here is my current code. It's a naive implementation.
import System.Environment (getArgs)
minmax [] = Nothing
minmax [x] = Just (x, x)
minmax (a:b:xs) = Just $ minmax' xs $ sort a b
where minmax' [] lohi = lohi
minmax' [x] lohi@(lo,…
user1685095
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1
vote
1 answer
Cannot install Haskell package stream-fusion-0.1.2.5: Ambiguous occurence
I'm trying to build the project Barbarosa which requires the package stream-fusion-0.1.2.5. However cabal install fails with the following
[3 of 3] Compiling Control.Monad.Stream ( Control/Monad/Stream.hs,…
xji
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0
votes
1 answer
Which compilers today are capable of converting (map f (map g h)) into (map (f . g) h)?
Many techniques are used for this means, from as simple as Short Cut Fusion to elaborate Stream Fusion. I'm aware compilers such as GHC and MLTon rely considerably on this technique. Are there other compilers in existence that do so?
MaiaVictor
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