gonum.org/v1/gonum v0.17.0: floats

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 gonum.org/v1/gonum/floats in pkg:golang/gonum.org/v1/gonum@v0.17.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/gonum.org/v1/gonum@v0.17.0
Demonstrate these symbols/APIs:
  - gonum.org/v1/gonum/floats

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:f533f51a9e7ac99176aaafda0e813f0887d32f24b6ea958542bcf3bbd2deeb5f","contract":["floats.Dot computes the dot product of two float64 slices","floats.Dot panics when slice lengths do not match","floats.Add adds elements of one slice to another element-wise in place","floats.Span populates a slice with linearly spaced values between lower and upper bounds","floats.EqualApprox returns true for float64 slices equal within a given tolerance"],"goal":"verify gonum.org/v1/gonum/floats in pkg:golang/gonum.org/v1/gonum@v0.17.0","kind":"HOW","packages":["pkg:golang/gonum.org/v1/gonum@v0.17.0"],"schemaVersion":1,"symbols":["gonum.org/v1/gonum/floats"]},"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/gonum.org/v1/gonum@v0.17.0"],"schemaVersion":1,"subject":"pkg:golang/gonum.org/v1/gonum@v0.17.0","symbols":["gonum.org/v1/gonum/floats"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require gonum.org/v1/gonum v0.17.0

gonum.org/v1/gonum v0.17.0 h1:VbpOemQlsSMrYmn7T2OUvQ4dqxQXU+ouZFQsZOx50z4=
gonum.org/v1/gonum v0.17.0/go.mod h1:El3tOrEuMpv2UdMrbNlKEh9vd86bmQ6vqIcDwxEOc1E=

package main

import (
	"fmt"

	"gonum.org/v1/gonum/floats"
)

func main() {
	// Generate 5 evenly spaced values from 0.0 to 1.0
	grid := make([]float64, 5)
	floats.Span(grid, 0.0, 1.0)
	fmt.Printf("Span: %v\n", grid)

	// Compute dot product of two vectors
	a := []float64{1.0, 2.0, 3.0}
	b := []float64{4.0, 5.0, 6.0}
	dot := floats.Dot(a, b)
	fmt.Printf("Dot product: %.2f\n", dot)

	// Element-wise in-place addition
	floats.Add(a, b)
	fmt.Printf("Added: %v\n", a)
}

{
  "schemaVersion": 1,
  "goal": "verify gonum.org/v1/gonum/floats in pkg:golang/gonum.org/v1/gonum@v0.17.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/gonum.org/v1/gonum@v0.17.0"
  ],
  "symbols": [
    "gonum.org/v1/gonum/floats"
  ]
}

package main

import (
	"fmt"
	"math"
	"os"

	"gonum.org/v1/gonum/floats"
)

func main() {
	// Assertion 1: floats.Dot computes the dot product of two float64 slices
	a := []float64{1.0, 2.0, 3.0}
	b := []float64{4.0, 5.0, 6.0}
	gotDot := floats.Dot(a, b)
	expectedDot := 1.0*4.0 + 2.0*5.0 + 3.0*6.0
	if math.Abs(gotDot-expectedDot) > 1e-9 {
		fmt.Fprintf(os.Stderr, "FAIL: floats.Dot mismatch: got %f, want %f\n", gotDot, expectedDot)
		os.Exit(1)
	}

	// Assertion 2: floats.Dot panics when slice lengths do not match
	panicked := false
	func() {
		defer func() {
			if r := recover(); r != nil {
				panicked = true
			}
		}()
		floats.Dot([]float64{1.0, 2.0}, []float64{1.0})
	}()
	if !panicked {
		fmt.Fprintf(os.Stderr, "FAIL: floats.Dot did not panic on mismatched slice lengths\n")
		os.Exit(1)
	}

	// Assertion 3: floats.Add adds elements of one slice to another element-wise in place
	dst := []float64{1.5, 2.5, 3.5}
	src := []float64{0.5, 1.5, 2.5}
	floats.Add(dst, src)
	expectedSum := []float64{2.0, 4.0, 6.0}
	if !floats.Equal(dst, expectedSum) {
		fmt.Fprintf(os.Stderr, "FAIL: floats.Add mismatch: got %v, want %v\n", dst, expectedSum)
		os.Exit(1)
	}

	// Assertion 4: floats.Span populates a slice with linearly spaced values between lower and upper bounds
	span := make([]float64, 5)
	floats.Span(span, 0.0, 1.0)
	expectedSpan := []float64{0.0, 0.25, 0.5, 0.75, 1.0}
	if !floats.EqualApprox(span, expectedSpan, 1e-9) {
		fmt.Fprintf(os.Stderr, "FAIL: floats.Span mismatch: got %v, want %v\n", span, expectedSpan)
		os.Exit(1)
	}

	// Assertion 5: floats.EqualApprox returns true for float64 slices equal within a given tolerance
	s1 := []float64{1.0, 2.00001, 3.0}
	s2 := []float64{1.0, 2.00002, 3.0}
	if !floats.EqualApprox(s1, s2, 1e-4) {
		fmt.Fprintf(os.Stderr, "FAIL: floats.EqualApprox should return true for small delta\n")
		os.Exit(1)
	}
	if floats.EqualApprox(s1, s2, 1e-6) {
		fmt.Fprintf(os.Stderr, "FAIL: floats.EqualApprox should return false for delta larger than tol\n")
		os.Exit(1)
	}

	fmt.Println("All gonum floats contract assertions passed.")
}