forked from TrueCloudLab/frostfs-http-gw
Make minor refactoring
Signed-off-by: Pavel Korotkov <pavel@nspcc.ru>
This commit is contained in:
parent
f7007f2085
commit
c21324bf77
1 changed files with 23 additions and 23 deletions
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@ -2,26 +2,13 @@ package connections
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import "math/rand"
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// https://www.keithschwarz.com/darts-dice-coins/
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// See Vose's Alias Method (https://www.keithschwarz.com/darts-dice-coins/).
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type Sampler struct {
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randomGenerator *rand.Rand
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probabilities []float64
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alias []int
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}
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type workList []int
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func (wl *workList) push(e int) {
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*wl = append(*wl, e)
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}
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func (wl *workList) pop() int {
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l := len(*wl) - 1
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n := (*wl)[l]
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*wl = (*wl)[:l]
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return n
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}
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func NewSampler(probabilities []float64, source rand.Source) *Sampler {
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sampler := &Sampler{}
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var (
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@ -39,28 +26,28 @@ func NewSampler(probabilities []float64, source rand.Source) *Sampler {
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}
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for i, pi := range p {
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if pi < 1 {
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small = append(small, i)
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small.add(i)
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} else {
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large = append(large, i)
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large.add(i)
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}
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}
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for len(large) > 0 && len(small) > 0 {
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l, g := small.pop(), large.pop()
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for len(small) > 0 && len(large) > 0 {
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l, g := small.remove(), large.remove()
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sampler.probabilities[l] = p[l]
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sampler.alias[l] = g
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p[g] = (p[g] + p[l]) - 1
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p[g] = p[g] + p[l] - 1
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if p[g] < 1 {
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small.push(g)
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small.add(g)
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} else {
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large.push(g)
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large.add(g)
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}
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}
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for len(large) > 0 {
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g := large.pop()
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g := large.remove()
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sampler.probabilities[g] = 1
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}
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for len(small) > 0 {
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l := small.pop()
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l := small.remove()
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sampler.probabilities[l] = 1
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}
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return sampler
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@ -74,3 +61,16 @@ func (g *Sampler) Next() int {
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}
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return g.alias[i]
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}
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type workList []int
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func (wl *workList) add(e int) {
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*wl = append(*wl, e)
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}
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func (wl *workList) remove() int {
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l := len(*wl) - 1
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n := (*wl)[l]
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*wl = (*wl)[:l]
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return n
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}
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