# std/bench

The runtime the `vyrn bench` transform links against. Only the synthesized bench `main` imports it, so its clock use never reaches a `run` or `build`.

## minOf

`fn`, at line 10.

```vyrn
fn minOf(xs: Array<Int64>) -> Int64
```

The minimum of a non-empty sample array.

## mean

`fn`, at line 21.

```vyrn
fn mean(xs: Array<Int64>) -> Int64
```

The truncating integer mean of a non-empty sample array.

## median

`fn`, at line 55.

```vyrn
fn median(xs: Array<Int64>) -> Int64
```

The median (upper-middle element) of a non-empty sample array.

## formatDuration

`fn`, at line 78.

```vyrn
fn formatDuration(ns: Int64) -> String
```

A nanosecond duration in human units: `ns` below one microsecond, then microseconds, `ms` or `s` with two fractional digits.

## padRight

`fn`, at line 92.

```vyrn
fn padRight(s: String, width: Int64) -> String
```

Right-pads `s` with spaces to `width` bytes; never truncates.

## BenchResult

`type`, at line 105.

```vyrn
type BenchResult = {
    name: String,
    minNs: Int64,
    medianNs: Int64,
    meanNs: Int64,
    samples: Int64,
    iters: Int64,
}
```

One bench's per-iteration statistics in nanoseconds, and the sample and iteration counts. Compare regressions on `minNs`, the least noisy.

## benchMeasure

`fn`, at line 123.

```vyrn
fn benchMeasure(name: String, body: fn() -> Unit) -> BenchResult
```

Times one bench body and returns its statistics:

```vyrn
1. warm up for about 50 ms, discarding results;
2. double the per-sample iteration count until one sample takes 1 ms;
3. collect samples until at least 31 and 500 ms, capped at 2 s;
4. compute min, median and mean per-iteration time.

```

The body keeps its work alive with `blackBox`, so the compiler cannot delete it between iterations.

## benchOne

`fn`, at line 179.

```vyrn
fn benchOne(name: String, width: Int64, body: fn() -> Unit)
```

Times one bench body and prints its report line. `width` is the label column width, computed from every bench name.

## benchJson

`fn`, at line 188.

```vyrn
fn benchJson(results: Array<BenchResult>, backend: String, opt: String) -> String
```

The `--json` bench report: compact, benches in declaration order, every number an integer: `{ backend, opt, benches: [ { name, minNs, medianNs, meanNs, samples, iters } ] }`.

---

From https://vyrn-lang.github.io/docs/std/bench.html — generated by `site/export.vyrn` from the Vyrn repository.