lotus/chain/messagepool/block_proba.go
Steven Allen 5733c71c50 Lint everything
We were ignoring quite a few error cases, and had one case where we weren't
actually updating state where we wanted to. Unfortunately, if the linter doesn't
pass, nobody has any reason to actually check lint failures in CI.

There are three remaining XXXs marked in the code for lint.
2020-08-20 20:46:36 -07:00

103 lines
2.0 KiB
Go

package messagepool
import (
"math"
"sync"
)
var noWinnersProbCache []float64
var noWinnersProbOnce sync.Once
func noWinnersProb() []float64 {
noWinnersProbOnce.Do(func() {
poissPdf := func(x float64) float64 {
const Mu = 5
lg, _ := math.Lgamma(x + 1)
result := math.Exp((math.Log(Mu) * x) - lg - Mu)
return result
}
out := make([]float64, 0, MaxBlocks)
for i := 0; i < MaxBlocks; i++ {
out = append(out, poissPdf(float64(i)))
}
noWinnersProbCache = out
})
return noWinnersProbCache
}
var noWinnersProbAssumingCache []float64
var noWinnersProbAssumingOnce sync.Once
func noWinnersProbAssumingMoreThanOne() []float64 {
noWinnersProbAssumingOnce.Do(func() {
cond := math.Log(-1 + math.Exp(5))
poissPdf := func(x float64) float64 {
const Mu = 5
lg, _ := math.Lgamma(x + 1)
result := math.Exp((math.Log(Mu) * x) - lg - cond)
return result
}
out := make([]float64, 0, MaxBlocks)
for i := 0; i < MaxBlocks; i++ {
out = append(out, poissPdf(float64(i+1)))
}
noWinnersProbAssumingCache = out
})
return noWinnersProbAssumingCache
}
func binomialCoefficient(n, k float64) float64 {
if k > n {
return math.NaN()
}
r := 1.0
for d := 1.0; d <= k; d++ {
r *= n
r /= d
n--
}
return r
}
func (mp *MessagePool) blockProbabilities(tq float64) []float64 {
noWinners := noWinnersProbAssumingMoreThanOne()
p := 1 - tq
binoPdf := func(x, trials float64) float64 {
// based on https://github.com/atgjack/prob
if x > trials {
return 0
}
if p == 0 {
if x == 0 {
return 1.0
}
return 0.0
}
if p == 1 {
if x == trials {
return 1.0
}
return 0.0
}
coef := binomialCoefficient(trials, x)
pow := math.Pow(p, x) * math.Pow(1-p, trials-x)
if math.IsInf(coef, 0) {
return 0
}
return coef * pow
}
out := make([]float64, 0, MaxBlocks)
for place := 0; place < MaxBlocks; place++ {
var pPlace float64
for otherWinners, pCase := range noWinners {
pPlace += pCase * binoPdf(float64(place), float64(otherWinners))
}
out = append(out, pPlace)
}
return out
}