1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
package stats_test
import (
"fmt"
"testing"
"github.com/montanaflynn/stats"
)
type distanceFunctionType func(stats.Float64Data, stats.Float64Data) (float64, error)
var minkowskiDistanceTestMatrix = []struct {
dataPointX []float64
dataPointY []float64
lambda float64
distance float64
}{
{[]float64{2, 3, 4, 5, 6, 7, 8}, []float64{8, 7, 6, 5, 4, 3, 2}, 1, 24},
{[]float64{2, 3, 4, 5, 6, 7, 8}, []float64{8, 7, 6, 5, 4, 3, 2}, 2, 10.583005244258363},
{[]float64{2, 3, 4, 5, 6, 7, 8}, []float64{8, 7, 6, 5, 4, 3, 2}, 99, 6},
}
var distanceTestMatrix = []struct {
dataPointX []float64
dataPointY []float64
distance float64
distanceFunction distanceFunctionType
}{
{[]float64{2, 3, 4, 5, 6, 7, 8}, []float64{8, 7, 6, 5, 4, 3, 2}, 6, stats.ChebyshevDistance},
{[]float64{2, 3, 4, 5, 6, 7, 8}, []float64{8, 7, 6, 5, 4, 3, 2}, 24, stats.ManhattanDistance},
{[]float64{2, 3, 4, 5, 6, 7, 8}, []float64{8, 7, 6, 5, 4, 3, 2}, 10.583005244258363, stats.EuclideanDistance},
}
func TestDataSetDistances(t *testing.T) {
// Test Minkowski Distance with different lambda values.
for _, testData := range minkowskiDistanceTestMatrix {
distance, err := stats.MinkowskiDistance(testData.dataPointX, testData.dataPointY, testData.lambda)
if err != nil && distance != testData.distance {
t.Errorf("Failed to compute Minkowski distance.")
}
_, err = stats.MinkowskiDistance([]float64{}, []float64{}, 3)
if err == nil {
t.Errorf("Empty slices should have resulted in an error")
}
_, err = stats.MinkowskiDistance([]float64{1, 2, 3}, []float64{1, 4}, 3)
if err == nil {
t.Errorf("Different length slices should have resulted in an error")
}
_, err = stats.MinkowskiDistance([]float64{999, 999, 999}, []float64{1, 1, 1}, 1000)
if err == nil {
t.Errorf("Infinite distance should have resulted in an error")
}
}
// Compute distance with the help of all algorithms.
for _, testSet := range distanceTestMatrix {
distance, err := testSet.distanceFunction(testSet.dataPointX, testSet.dataPointY)
if err != nil && testSet.distance != distance {
t.Errorf("Failed to compute distance.")
}
_, err = testSet.distanceFunction([]float64{}, []float64{})
if err == nil {
t.Errorf("Empty slices should have resulted in an error")
}
}
}
func ExampleChebyshevDistance() {
d1 := []float64{2, 3, 4, 5, 6, 7, 8}
d2 := []float64{8, 7, 6, 5, 4, 3, 2}
cd, _ := stats.ChebyshevDistance(d1, d2)
fmt.Println(cd)
// Output: 6
}
|
