Run multiple benchmarks and compare them. This is useful when optimizing data structures or other situations where you can make apples-to-apples comparisons between different approaches.

rank "initialize"
    (\f -> f 100 identity)
    [ ( "optimized", Array.Optimized.initialize )
    , ( "core", Array.initialize )
    ]

With the first argument you specify how you run the functions in the list.