TheAlgorithms/Go · error

x must be < n - given values are x=

Error message

x must be < n - given values are x=%d, n=%d

What it means

splitInt distributes x items uniformly across n workers/channels; it requires x >= n so every slot gets at least one item (MonteCarloPiConcurrent passes total iterations vs worker count), and reports both values when the precondition fails.

Solutions

1. Ensure the number of iterations is at least the number of workers before calling
2. Clamp n to min(n, x) at the call site
3. Skip the split entirely when x < n and handle x items in one batch

When it happens

Trigger: Thrown at math/pi/montecarlopi.go:78 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of TheAlgorithms/Go@5ba447ec5f (2026-09-02). Data as JSON: /api/errors/b3e49898b6a4c74f. Report an issue: GitHub.

Appendix: source

Thrown at math/pi/montecarlopi.go:78

// the number of points which where within the circle of center 0 and radius 1 (unit circle)
func drawPoints(n int, c chan<- int) {
	rnd := rand.New(rand.NewSource(time.Now().UnixNano()))
	inside := 0
	for i := 0; i < n; i++ {
		x, y := rnd.Float64(), rnd.Float64()
		if x*x+y*y <= 1 {
			inside++
		}
	}
	c <- inside
}

// splitInt takes an integer x and splits it within an integer slice of length n in the most uniform
// way possible.
// For example, splitInt(10, 3) will return []int{4, 3, 3}, nil
func splitInt(x int, n int) ([]int, error) {
	if x < n {
		return nil, fmt.Errorf("x must be < n - given values are x=%d, n=%d", x, n)
	}
	split := make([]int, n)
	if x%n == 0 {
		for i := 0; i < n; i++ {
			split[i] = x / n
		}
	} else {
		limit := x % n
		for i := 0; i < limit; i++ {
			split[i] = x/n + 1
		}
		for i := limit; i < n; i++ {
			split[i] = x / n
		}
	}
	return split, nil
}

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