gonum.org/v1/gonum v0.17.0

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 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

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:a279f7b727a501605041eff71ea94eaabde9ff858cfa23eea7b99bc6da3b261b","contract":["mat.NewDense creates a dense matrix with specified dimensions and values","mat.Dense.At and Set retrieve and update individual matrix elements","mat.Dense.Mul computes the matrix product of two dense matrices","mat.Dense.Add computes the element-wise sum of two dense matrices","mat.Dense.Scale multiplies all matrix elements by a scalar value","mat.Det calculates the determinant of a square matrix"],"goal":"verify pkg:golang/gonum.org/v1/gonum@v0.17.0","kind":"HOW","packages":["pkg:golang/gonum.org/v1/gonum@v0.17.0"],"schemaVersion":1},"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","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/mat"
)

func main() {
	// Create two 2x2 matrices
	a := mat.NewDense(2, 2, []float64{
		1, 2,
		3, 4,
	})
	b := mat.NewDense(2, 2, []float64{
		5, 6,
		7, 8,
	})

	// Matrix multiplication: c = a * b
	var c mat.Dense
	c.Mul(a, b)

	r, cols := c.Dims()
	fmt.Printf("Multiplication result (%dx%d):\n", r, cols)
	for i := 0; i < r; i++ {
		for j := 0; j < cols; j++ {
			fmt.Printf("%6.1f ", c.At(i, j))
		}
		fmt.Println()
	}

	// Determinant of matrix a
	det := mat.Det(a)
	fmt.Printf("det(a) = %.1f\n", det)
}

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

package main

import (
	"fmt"
	"math"
	"os"

	"gonum.org/v1/gonum/mat"
)

func main() {
	// Assertion 1: mat.NewDense creates a dense matrix with specified dimensions and values
	dataA := []float64{
		1, 2,
		3, 4,
	}
	a := mat.NewDense(2, 2, dataA)
	r, c := a.Dims()
	if r != 2 || c != 2 {
		fmt.Fprintf(os.Stderr, "FAIL: expected dims (2, 2), got (%d, %d)\n", r, c)
		os.Exit(1)
	}
	if a.At(0, 0) != 1 || a.At(0, 1) != 2 || a.At(1, 0) != 3 || a.At(1, 1) != 4 {
		fmt.Fprintf(os.Stderr, "FAIL: initial values mismatch\n")
		os.Exit(1)
	}

	// Assertion 2: mat.Dense.At and Set retrieve and update individual matrix elements
	aCopy := mat.DenseCopyOf(a)
	aCopy.Set(0, 1, 42.0)
	if aCopy.At(0, 1) != 42.0 {
		fmt.Fprintf(os.Stderr, "FAIL: Set/At failed, expected 42.0, got %f\n", aCopy.At(0, 1))
		os.Exit(1)
	}
	if a.At(0, 1) != 2.0 {
		fmt.Fprintf(os.Stderr, "FAIL: DenseCopyOf mutated original matrix\n")
		os.Exit(1)
	}

	// Assertion 3: mat.Dense.Mul computes the matrix product of two dense matrices
	b := mat.NewDense(2, 2, []float64{
		5, 6,
		7, 8,
	})
	var prod mat.Dense
	prod.Mul(a, b)
	expectedProd := [2][2]float64{
		{19, 22},
		{43, 50},
	}
	for i := 0; i < 2; i++ {
		for j := 0; j < 2; j++ {
			if math.Abs(prod.At(i, j)-expectedProd[i][j]) > 1e-9 {
				fmt.Fprintf(os.Stderr, "FAIL: Mul mismatch at (%d, %d): got %f, want %f\n", i, j, prod.At(i, j), expectedProd[i][j])
				os.Exit(1)
			}
		}
	}

	// Assertion 4: mat.Dense.Add computes the element-wise sum of two dense matrices
	var sum mat.Dense
	sum.Add(a, b)
	expectedSum := [2][2]float64{
		{6, 8},
		{10, 12},
	}
	for i := 0; i < 2; i++ {
		for j := 0; j < 2; j++ {
			if math.Abs(sum.At(i, j)-expectedSum[i][j]) > 1e-9 {
				fmt.Fprintf(os.Stderr, "FAIL: Add mismatch at (%d, %d): got %f, want %f\n", i, j, sum.At(i, j), expectedSum[i][j])
				os.Exit(1)
			}
		}
	}

	// Assertion 5: mat.Dense.Scale multiplies all matrix elements by a scalar value
	var scaled mat.Dense
	scaled.Scale(2.5, a)
	expectedScaled := [2][2]float64{
		{2.5, 5.0},
		{7.5, 10.0},
	}
	for i := 0; i < 2; i++ {
		for j := 0; j < 2; j++ {
			if math.Abs(scaled.At(i, j)-expectedScaled[i][j]) > 1e-9 {
				fmt.Fprintf(os.Stderr, "FAIL: Scale mismatch at (%d, %d): got %f, want %f\n", i, j, scaled.At(i, j), expectedScaled[i][j])
				os.Exit(1)
			}
		}
	}

	// Assertion 6: mat.Det calculates the determinant of a square matrix
	det := mat.Det(a)
	if math.Abs(det-(-2.0)) > 1e-9 {
		fmt.Fprintf(os.Stderr, "FAIL: Det mismatch: got %f, want -2.0\n", det)
		os.Exit(1)
	}

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