func TestNDCGAtK(t *testing.T) · rank 1 discount

Read the equation

This relation defines rank 1 discount in the source section “func TestNDCGAtK(t *testing.T) · rank 1 discount”. Uses logarithmic scaling; its base and the positivity of its argument matter. Its interpretation depends on the source’s stated variables and conditions; this record does not assign an unprovided physical or cognitive meaning to them.

Terms & definitions

The recovered passage does not supply a separate symbol table. Read the source context for the notation used in this version; familiar letters may carry different meanings in other builds.

How it works

1. Read rank 1 discount as the quantity being defined or updated by this relation.

2. Uses logarithmic scaling; its base and the positivity of its argument matter.

3. Use this version’s variable definitions and update order. The same symbol may be assigned a different meaning in another build.

Assumptions & limits

• This source expression was recovered from the pinned code revision. Its presence does not establish that the associated program was built, run, or scientifically validated.

Original context

	}
}

// ---------- NDCGAtK ----------

func TestNDCGAtK(t *testing.T) {
	// Hand computed reference values. The discount for the id at one based rank r is 1/log2(r+1).
	// rank 1 discount = 1/log2(2) = 1.0
	// rank 2 discount = 1/log2(3) = 0.6309297535714574
	// rank 3 discount = 1/log2(4) = 0.5
	d1, d2, d3 := 1.0, 1.0/math.Log2(3), 0.5

	tests := []struct {
		name     string
		ranked   []string
		relevant map[string]bool
		k        int
		want     float64

rank 1 discount = 1/log2(2) = 1.0

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