github.com/beorn7/perks v1.0.1: quantile.NewLowBiased

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify github.com/beorn7/perks/quantile.NewLowBiased in pkg:golang/github.com/beorn7/perks@v1.0.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/beorn7/perks@v1.0.1
Demonstrate these symbols/APIs:
  - github.com/beorn7/perks/quantile.NewLowBiased

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:c08de18a09d2d75ed328a299d4d0494e0c9faf22609e8a633e11c529dc184cd7","contract":["quantile.NewLowBiased initializes a low-biased quantile Stream with zero observations","Stream.Insert adds float64 observations and Stream.Count tracks the total count","Stream.Query calculates low-rank quantiles within relative error guarantees","Stream.Samples returns retained sample representations from the stream","Stream.Reset clears stream observations and resets Count to zero"],"goal":"verify github.com/beorn7/perks/quantile.NewLowBiased in pkg:golang/github.com/beorn7/perks@v1.0.1","kind":"HOW","packages":["pkg:golang/github.com/beorn7/perks@v1.0.1"],"schemaVersion":1,"symbols":["github.com/beorn7/perks/quantile.NewLowBiased"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/beorn7/perks@v1.0.1"],"schemaVersion":1,"subject":"pkg:golang/github.com/beorn7/perks@v1.0.1","symbols":["github.com/beorn7/perks/quantile.NewLowBiased"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/beorn7/perks v1.0.1

github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=

package main

import (
	"fmt"

	"github.com/beorn7/perks/quantile"
)

func main() {
	// Configure a low-biased quantile stream with 0.01 relative error bound
	stream := quantile.NewLowBiased(0.01)

	// Stream synthetic observations (1.0 through 1000.0)
	for i := 1; i <= 1000; i++ {
		stream.Insert(float64(i))
	}

	fmt.Printf("Total observations: %d\n", stream.Count())
	fmt.Printf("p01 estimate: %.2f\n", stream.Query(0.01))
	fmt.Printf("p05 estimate: %.2f\n", stream.Query(0.05))
	fmt.Printf("p10 estimate: %.2f\n", stream.Query(0.10))
	fmt.Printf("p50 estimate: %.2f\n", stream.Query(0.50))

	// Inspect retained sample points
	samples := stream.Samples()
	fmt.Printf("Sample points retained: %d\n", len(samples))

	// Reset stream observations
	stream.Reset()
	fmt.Printf("Observations after reset: %d\n", stream.Count())
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/beorn7/perks/quantile.NewLowBiased in pkg:golang/github.com/beorn7/perks@v1.0.1",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/beorn7/perks@v1.0.1"
  ],
  "symbols": [
    "github.com/beorn7/perks/quantile.NewLowBiased"
  ]
}

package main

import (
	"fmt"
	"math"
	"os"

	"github.com/beorn7/perks/quantile"
)

func main() {
	// Assertion 1: quantile.NewLowBiased initializes a low-biased quantile Stream with zero observations
	{
		stream := quantile.NewLowBiased(0.01)
		if stream == nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected non-nil stream from NewLowBiased\n")
			os.Exit(1)
		}
		if count := stream.Count(); count != 0 {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected initial count 0, got %d\n", count)
			os.Exit(1)
		}
		if q0 := stream.Query(0.01); q0 != 0 {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected query 0 on empty stream, got %f\n", q0)
			os.Exit(1)
		}
	}

	// Assertion 2: Stream.Insert adds float64 observations and Stream.Count tracks the total count
	{
		stream := quantile.NewLowBiased(0.01)
		for i := 1; i <= 250; i++ {
			stream.Insert(float64(i))
		}
		if count := stream.Count(); count != 250 {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected count 250, got %d\n", count)
			os.Exit(1)
		}

		for i := 251; i <= 500; i++ {
			stream.Insert(float64(i))
		}
		if count := stream.Count(); count != 500 {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected count 500, got %d\n", count)
			os.Exit(1)
		}
	}

	// Assertion 3: Stream.Query calculates low-rank quantiles within relative error guarantees
	{
		stream := quantile.NewLowBiased(0.01)
		n := 1000
		for i := 1; i <= n; i++ {
			stream.Insert(float64(i))
		}

		p01 := stream.Query(0.01)
		if math.Abs(p01-10.0) > 5.0 {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: expected p01 near 10.0, got %f\n", p01)
			os.Exit(1)
		}

		p05 := stream.Query(0.05)
		if math.Abs(p05-50.0) > 10.0 {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: expected p05 near 50.0, got %f\n", p05)
			os.Exit(1)
		}

		p10 := stream.Query(0.10)
		if math.Abs(p10-100.0) > 15.0 {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: expected p10 near 100.0, got %f\n", p10)
			os.Exit(1)
		}

		p50 := stream.Query(0.50)
		if math.Abs(p50-500.0) > 30.0 {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: expected p50 near 500.0, got %f\n", p50)
			os.Exit(1)
		}
	}

	// Assertion 4: Stream.Samples returns retained sample representations from the stream
	{
		stream := quantile.NewLowBiased(0.01)
		for i := 1; i <= 600; i++ {
			stream.Insert(float64(i))
		}
		samples := stream.Samples()
		if len(samples) == 0 {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: expected non-empty samples slice\n")
			os.Exit(1)
		}
		for _, s := range samples {
			if s.Value <= 0 || s.Width <= 0 {
				fmt.Fprintf(os.Stderr, "assertion 4 failed: invalid sample value or width: %+v\n", s)
				os.Exit(1)
			}
		}
	}

	// Assertion 5: Stream.Reset clears stream observations and resets Count to zero
	{
		stream := quantile.NewLowBiased(0.01)
		for i := 1; i <= 100; i++ {
			stream.Insert(float64(i))
		}
		if stream.Count() != 100 {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: expected count 100 before reset, got %d\n", stream.Count())
			os.Exit(1)
		}

		stream.Reset()
		if count := stream.Count(); count != 0 {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: expected count 0 after reset, got %d\n", count)
			os.Exit(1)
		}
		if q0 := stream.Query(0.01); q0 != 0 {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: expected query 0 on empty stream, got %f\n", q0)
			os.Exit(1)
		}
	}

	fmt.Println("All contract assertions passed successfully.")
}