geometric_mean_test.go

package statistics

import (
	"fmt"
	"testing"
)

func ExampleGeometricMean() {
	mean := GeometricMean(1, 1000)
	fmt.Printf("The geometric mean of [1 1000] is %0.3f.\n", mean)

	// Output:
	// The geometric mean of [1 1000] is 31.623.
}

func TestGeometricMean(t *testing.T) {
	cases := []testArrayCase{
		{
			name:     "no numbers",
			input:    []uint{},
			expected: "NaN",
		},
		{
			name:     "has zero",
			input:    []uint{5, 0},
			expected: "0",
		},
		{
			name:     "two numbers",
			input:    []uint{5, 15},
			expected: "8.660254037844387",
		},
		{
			name:     "zero with negative number",
			input:    []int{-5, 5},
			expected: "NaN",
		},
		{
			name:     "two floats",
			input:    []float32{2.5, 4.5},
			expected: "3.3541019662496847",
		},
	}
	for _, c := range cases {
		c := c
		t.Run(c.name, func(t *testing.T) {
			t.Parallel()
			var actual float64
			switch c.input.(type) {
			case []uint64:
				actual = GeometricMean(c.input.([]uint64)...)
			case []uint:
				actual = GeometricMean(c.input.([]uint)...)
			case []int:
				actual = GeometricMean(c.input.([]int)...)
			case []int32:
				actual = GeometricMean(c.input.([]int32)...)
			case []float32:
				actual = GeometricMean(c.input.([]float32)...)
			case []float64:
				actual = GeometricMean(c.input.([]float64)...)
			}
			if fmt.Sprintf("%v", actual) != c.expected {
				t.Logf("expected %v, got %v", c.expected, actual)
				t.FailNow()
			}
		})
	}
}

func BenchmarkGeometricMean(b *testing.B) {
	for i := 0; i < b.N; i++ {
		GeometricMean(i, i-5, i+3, i-8)
	}
}