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almost_equal.go
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/
almost_equal.go
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package internal
import (
"math"
)
// minNormalFloat64 is the smallest positive normal value of type float64.
var minNormalFloat64 = math.Float64frombits(0x0010000000000000)
// AlmostEqualFloat64 returns true if a and b are equal within a relative error
// of epsilon. See http://floating-point-gui.de/errors/comparison/ for the
// details of the applied method.
//
// This function is copy/paste to avoid a dependency.
// https://github.com/beorn7/floats
func AlmostEqualFloat64(a, b, epsilon float64) bool {
if a == b {
return true
}
absA := math.Abs(a)
absB := math.Abs(b)
diff := math.Abs(a - b)
if a == 0 || b == 0 || absA+absB < minNormalFloat64 {
return diff < epsilon*minNormalFloat64
}
return diff/math.Min(absA+absB, math.MaxFloat64) < epsilon
}
// AlmostEqualFloat64s is the slice form of AlmostEqualFloat64.
func AlmostEqualFloat64s(a, b []float64, epsilon float64) bool {
if len(a) != len(b) {
return false
}
for i := range a {
if !AlmostEqualFloat64(a[i], b[i], epsilon) {
return false
}
}
return true
}