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// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package trace
import (
"math/rand"
"testing"
)
func TestMUD(t *testing.T) {
// Insert random uniforms and check histogram mass and
// cumulative sum approximations.
rnd := rand.New(rand.NewSource(42))
mass := 0.0
var mud mud
for i := 0; i < 100; i++ {
area, l, r := rnd.Float64(), rnd.Float64(), rnd.Float64()
if rnd.Intn(10) == 0 {
r = l
}
t.Log(l, r, area)
mud.add(l, r, area)
mass += area
// Check total histogram weight.
hmass := 0.0
for _, val := range mud.hist {
hmass += val
}
if !aeq(mass, hmass) {
t.Fatalf("want mass %g, got %g", mass, hmass)
}
// Check inverse cumulative sum approximations.
for j := 0.0; j < mass; j += mass * 0.099 {
mud.setTrackMass(j)
l, u, ok := mud.approxInvCumulativeSum()
inv, ok2 := mud.invCumulativeSum(j)
if !ok || !ok2 {
t.Fatalf("inverse cumulative sum failed: approx %v, exact %v", ok, ok2)
}
if !(l <= inv && inv < u) {
t.Fatalf("inverse(%g) = %g, not ∈ [%g, %g)", j, inv, l, u)
}
}
}
}
func TestMUDTracking(t *testing.T) {
// Test that the tracked mass is tracked correctly across
// updates.
rnd := rand.New(rand.NewSource(42))
const uniforms = 100
for trackMass := 0.0; trackMass < uniforms; trackMass += uniforms / 50 {
var mud mud
mass := 0.0
mud.setTrackMass(trackMass)
for i := 0; i < uniforms; i++ {
area, l, r := rnd.Float64(), rnd.Float64(), rnd.Float64()
mud.add(l, r, area)
mass += area
l, u, ok := mud.approxInvCumulativeSum()
inv, ok2 := mud.invCumulativeSum(trackMass)
if mass < trackMass {
if ok {
t.Errorf("approx(%g) = [%g, %g), but mass = %g", trackMass, l, u, mass)
}
if ok2 {
t.Errorf("exact(%g) = %g, but mass = %g", trackMass, inv, mass)
}
} else {
if !ok {
t.Errorf("approx(%g) failed, but mass = %g", trackMass, mass)
}
if !ok2 {
t.Errorf("exact(%g) failed, but mass = %g", trackMass, mass)
}
if ok && ok2 && !(l <= inv && inv < u) {
t.Errorf("inverse(%g) = %g, not ∈ [%g, %g)", trackMass, inv, l, u)
}
}
}
}
}
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