How do I compare performance benchmarks in Haskell using Criterion?

What is Criterion in Haskell?

Criterion is a benchmarking library for Haskell that allows you to measure and compare the performance of your code.

How do I set up Criterion for my Haskell project?

You can set up Criterion by adding it to your project's dependencies in the .cabal file or using Stack. Then, import it in your Haskell files.

Can you show me an example of a simple benchmark?

Sure! Here's a basic example:

import Criterion.Main

main :: IO ()
main = defaultMain [
    bgroup "example" [
        bench "fib 20" $ whnf fib 20,
        bench "fib 30" $ whnf fib 30
    ]
]

fib :: Integer -> Integer
fib 0 = 0
fib 1 = 1
fib n = fib (n - 1) + fib (n - 2)

How do I interpret the results from Criterion?

Criterion provides detailed output, including mean execution time, standard deviation, and more. Look for the 'mean' value to understand the average performance.