-- # Benchmarking
--
-- Suppose we write a simple program that sums the squares of some integers:

def main (n: i32): i32 =
  reduce (+) 0 (map (**2) (0..<n))

-- We can benchmark this program by adding a test stanza to the source
-- file (say, `benchmarking.fut`) that looks like this:
--
--     -- ==
--     -- compiled input {       1000 } output {   332833500 }
--     -- compiled input {    1000000 } output {   584144992 }
--     -- compiled input { 1000000000 } output { -2087553280 }
--
-- The `output` parts are optional.  We then use `futhark bench`:
--
-- ```
-- $ futhark bench benchmarking.fut
-- Compiling benchmarking.fut...
-- Results for benchmarking.fut:
-- dataset #0 ("1000i32"):             0.20us (avg. of 10 runs; RSD: 2.00)
-- dataset #1 ("1000000i32"):        290.00us (avg. of 10 runs; RSD: 0.03)
-- dataset #2 ("1000000000i32"):  270154.20us (avg. of 10 runs; RSD: 0.01)
-- ```
--
-- This will use the default (`c`) backend.  Things are more
-- interesting with `opencl`:
--
-- ```
-- $ futhark bench --backend=opencl benchmarking.fut
-- Compiling benchmarking.fut...
-- Results for benchmarking.fut:
-- dataset #0 ("1000i32"):            49.70us (avg. of 10 runs; RSD: 0.18)
-- dataset #1 ("1000000i32"):         44.40us (avg. of 10 runs; RSD: 0.02)
-- dataset #2 ("1000000000i32"):    1693.80us (avg. of 10 runs; RSD: 0.04)
-- ```
--
-- # See also
--
-- The [manpage for `futhark
-- bench`](https://futhark.readthedocs.io/en/stable/man/futhark-bench.html).