package main

import (
	"math/rand"
)

// Returns a random value from a laplace
// distribution with parameters u and b.
func laplaceDist(u, b float64) float64 {
	uniform := rand.Float64()
	uniform -= 0.5
	return u - b*sgn(uniform)*math.Log(1-2*math.Abs(uniform))
}

// The signum function
func sgn(x float64) flot64 {
	if x < 0 {
		return -1
	}
	if x > 0 {
		return 1
	}
	return 0
}