kercylan98
103 lines
2.4 KiB
Go
103 lines
2.4 KiB
Go
package random
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import (
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"math/rand"
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"time"
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)
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// ProbabilitySlice 按概率随机从切片中产生一个数据并返回命中的对象及是否未命中
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// - 当总概率小于 1 将会发生未命中的情况
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func ProbabilitySlice[T any](getProbabilityHandle func(data T) float64, data ...T) (hit T, miss bool) {
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hit, _, miss = ProbabilitySliceIndex(getProbabilityHandle, data...)
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return hit, miss
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}
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// ProbabilitySliceIndex 按概率随机从切片中产生一个数据并返回命中的对象及对象索引以及是否未命中
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// - 当总概率小于 1 将会发生未命中的情况
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func ProbabilitySliceIndex[T any](getProbabilityHandle func(data T) float64, data ...T) (hit T, index int, miss bool) {
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rd := rand.New(rand.NewSource(time.Now().UnixNano()))
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var total float64
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for _, d := range data {
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total += getProbabilityHandle(d)
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}
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scaleFactor := 1.0
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var indexLimit = len(data)
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var limitP = 0.0
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if total > 1.0 {
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scaleFactor = 1.0 / total
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} else if total < 1.0 {
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indexLimit++
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limitP = 1.0 - total
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}
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var overlayProbability []float64
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cumulativeProbability := 0.0
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for i := 0; i < indexLimit; i++ {
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if i < len(data) {
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cumulativeProbability += getProbabilityHandle(data[i]) * scaleFactor
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overlayProbability = append(overlayProbability, cumulativeProbability)
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} else {
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cumulativeProbability += limitP * scaleFactor
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overlayProbability = append(overlayProbability, cumulativeProbability)
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}
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}
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if total < 1.0 {
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overlayProbability[len(overlayProbability)-1] = 1.0
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}
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var r = rd.Float64()
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var i, count = 0, len(overlayProbability)
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for i < count {
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h := int(uint(i+count) >> 1)
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if overlayProbability[h] <= r {
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i = h + 1
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} else {
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count = h
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}
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}
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if i >= len(data) {
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return hit, -1, true
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}
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hit = data[i]
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return hit, i, false
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}
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// Probability 输入一个概率，返回是否命中
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// - 当 full 不为空时，将以 full 为基数，p 为分子，计算命中概率
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func Probability(p int, full ...int) bool {
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var f = 100
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if len(full) > 0 {
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f = full[0]
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if f <= 0 {
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f = 100
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} else if p > f {
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return true
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}
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}
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r := Int(1, f)
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return r <= p
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}
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// ProbabilityChooseOne 输入一组概率，返回命中的索引
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func ProbabilityChooseOne(ps ...int) int {
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var f int
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for _, p := range ps {
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f += p
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}
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if f <= 0 {
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panic("total probability less than or equal to 0")
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}
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r := Int(1, f)
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for i, p := range ps {
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if r <= p {
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return i
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}
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r -= p
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}
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panic("probability choose one error")
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}
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