45 lines
1.1 KiB
Go
45 lines
1.1 KiB
Go
package math
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import (
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"math"
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)
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// Sign 符号函数（Sign function，简称sgn）是一个逻辑函数，用以判断实数的正负号。为避免和英文读音相似的正弦函数（sine）混淆，它亦称为Signum function。
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func Sign[T int | int8 | int16 | int32 | int64 | float32 | float64](x T) T {
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switch {
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case x < 0: // x < 0 : -1
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return -1
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case x > 0: // x > 0 : +1
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return +1
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default: // x == 0 : 0
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return 0
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}
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}
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// Mean 计算给定数据的平均值
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func Mean(num []float64) float64 {
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var count = len(num)
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var sum float64 = 0
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for i := 0; i < count; i++ {
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sum += num[i]
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}
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return sum / float64(count)
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}
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// Variance 使用平均值计算给定数据的方差
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func Variance(mean float64, num []float64) float64 {
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var count = len(num)
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var variance float64 = 0
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for i := 0; i < count; i++ {
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variance += math.Pow(num[i]-mean, 2)
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}
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return variance / float64(count)
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}
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// StandardDeviation 使用方差计算给定数据的标准偏差
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func StandardDeviation(num []float64) float64 {
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var mean = Mean(num)
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var variance = Variance(mean, num)
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return math.Sqrt(variance)
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}
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