go exponential random distribution example

main.go

package main

import (
    crand "crypto/rand"
    "encoding/binary"
    "fmt"
    "time"

    "golang.org/x/exp/rand"
    "gonum.org/v1/gonum/stat/distuv"
)

func main() {
    dist := distuv.Exponential{Rate: 10, Src: newPCGSource()}
    for i := 0; i < 10; i++ {
        fmt.Println(dist.Rand() * 30)
    }
}

func newPCGSource() *rand.PCGSource {
    s := &rand.PCGSource{}
    s.Seed(randSeed())
    return s
}

func randSeed() uint64 {
    var b [8]byte
    _, err := crand.Read(b[:])
    if err != nil {
        return uint64(time.Now().UnixNano())
    }
    return binary.LittleEndian.Uint64(b[:])
}