Remove unused solver algorithms (SA, hybrid, original hill climb)

This commit is contained in:
Ian Gulliver
2026-02-16 12:43:32 -08:00
parent d40f92628a
commit 16e1080e76
2 changed files with 26 additions and 805 deletions

View File

@@ -139,18 +139,10 @@ func printStats(label string, results []runResult, runs int) {
func main() {
dir := flag.String("dir", "tmp", "directory with trip/students/constraints JSON files")
runs := flag.Int("runs", 20, "number of solver runs per parameter set")
algo := flag.String("algo", "both", "algorithm: hillclimb, fast, sa, hybrid, both, all")
numRandom := flag.String("random", "30", "comma-separated random placement counts (hillclimb)")
numPerturb := flag.String("perturb", "200", "comma-separated perturbation counts (hillclimb)")
perturbMin := flag.Int("pmin", 2, "perturbation min groups (hillclimb)")
perturbMax := flag.Int("pmax", 5, "perturbation max groups (hillclimb)")
saRestarts := flag.String("restarts", "20", "comma-separated SA/hybrid restart counts")
saSteps := flag.String("steps", "10000", "comma-separated SA step counts")
hybridSteps := flag.String("hsteps", "5000", "comma-separated hybrid SA step counts")
saTempHigh := flag.Float64("thigh", 5.0, "SA initial temperature")
saTempLow := flag.Float64("tlow", 0.01, "SA final temperature")
hybridTempHigh := flag.Float64("hthigh", 10.0, "hybrid SA initial temperature")
hybridTempLow := flag.Float64("htlow", 0.1, "hybrid SA final temperature")
numRandom := flag.String("random", "50", "comma-separated random placement counts")
numPerturb := flag.String("perturb", "750", "comma-separated perturbation counts")
perturbMin := flag.Int("pmin", 3, "perturbation min groups")
perturbMax := flag.Int("pmax", 8, "perturbation max groups")
flag.Parse()
tripBytes, err := os.ReadFile(*dir + "/1")
@@ -201,127 +193,32 @@ func main() {
fmt.Printf("Prefer Not multiple: %d, No Prefer cost: %d\n", trip.PreferNotMultiple, trip.NoPreferCost)
fmt.Printf("Runs per config: %d\n\n", *runs)
if *algo == "hillclimb" || *algo == "both" {
randomCounts := parseIntList(*numRandom)
perturbCounts := parseIntList(*numPerturb)
for _, nr := range randomCounts {
for _, np := range perturbCounts {
params := solver.Params{
NumRandom: nr,
NumPerturb: np,
PerturbMin: *perturbMin,
PerturbMax: *perturbMax,
}
var results []runResult
for run := range *runs {
rng := rand.New(rand.NewSource(int64(run * 31337)))
start := time.Now()
sols := solver.Solve(n, trip.RoomSize, trip.PreferNotMultiple, trip.NoPreferCost, constraints, params, rng)
elapsed := time.Since(start)
if len(sols) > 0 {
var assignments [][]int
for _, s := range sols {
assignments = append(assignments, s.Assignment)
}
results = append(results, runResult{sols[0].Score, assignments, elapsed})
}
}
label := fmt.Sprintf("hillclimb random=%d perturb=%d pmin=%d pmax=%d", nr, np, *perturbMin, *perturbMax)
printStats(label, results, *runs)
randomCounts := parseIntList(*numRandom)
perturbCounts := parseIntList(*numPerturb)
for _, nr := range randomCounts {
for _, np := range perturbCounts {
params := solver.Params{
NumRandom: nr,
NumPerturb: np,
PerturbMin: *perturbMin,
PerturbMax: *perturbMax,
}
}
}
if *algo == "fast" || *algo == "both" || *algo == "all" {
randomCounts := parseIntList(*numRandom)
perturbCounts := parseIntList(*numPerturb)
for _, nr := range randomCounts {
for _, np := range perturbCounts {
params := solver.Params{
NumRandom: nr,
NumPerturb: np,
PerturbMin: *perturbMin,
PerturbMax: *perturbMax,
}
var results []runResult
for run := range *runs {
rng := rand.New(rand.NewSource(int64(run * 31337)))
start := time.Now()
sols := solver.SolveFast(n, trip.RoomSize, trip.PreferNotMultiple, trip.NoPreferCost, constraints, params, rng)
elapsed := time.Since(start)
if len(sols) > 0 {
var assignments [][]int
for _, s := range sols {
assignments = append(assignments, s.Assignment)
}
results = append(results, runResult{sols[0].Score, assignments, elapsed})
var results []runResult
for run := range *runs {
rng := rand.New(rand.NewSource(int64(run * 31337)))
start := time.Now()
sols := solver.SolveFast(n, trip.RoomSize, trip.PreferNotMultiple, trip.NoPreferCost, constraints, params, rng)
elapsed := time.Since(start)
if len(sols) > 0 {
var assignments [][]int
for _, s := range sols {
assignments = append(assignments, s.Assignment)
}
results = append(results, runResult{sols[0].Score, assignments, elapsed})
}
label := fmt.Sprintf("fast random=%d perturb=%d pmin=%d pmax=%d", nr, np, *perturbMin, *perturbMax)
printStats(label, results, *runs)
}
}
}
if *algo == "sa" || *algo == "all" {
restartCounts := parseIntList(*saRestarts)
stepCounts := parseIntList(*saSteps)
for _, nr := range restartCounts {
for _, ns := range stepCounts {
params := solver.SAParams{
Restarts: nr,
Steps: ns,
TempHigh: *saTempHigh,
TempLow: *saTempLow,
}
var results []runResult
for run := range *runs {
rng := rand.New(rand.NewSource(int64(run * 31337)))
start := time.Now()
sols := solver.SolveSA(n, trip.RoomSize, trip.PreferNotMultiple, trip.NoPreferCost, constraints, params, rng)
elapsed := time.Since(start)
if len(sols) > 0 {
var assignments [][]int
for _, s := range sols {
assignments = append(assignments, s.Assignment)
}
results = append(results, runResult{sols[0].Score, assignments, elapsed})
}
}
label := fmt.Sprintf("sa restarts=%d steps=%d thigh=%.1f tlow=%.3f", nr, ns, *saTempHigh, *saTempLow)
printStats(label, results, *runs)
}
}
}
if *algo == "hybrid" || *algo == "both" || *algo == "all" {
restartCounts := parseIntList(*saRestarts)
stepCounts := parseIntList(*hybridSteps)
for _, nr := range restartCounts {
for _, ns := range stepCounts {
params := solver.HybridParams{
SARestarts: nr,
SASteps: ns,
TempHigh: *hybridTempHigh,
TempLow: *hybridTempLow,
}
var results []runResult
for run := range *runs {
rng := rand.New(rand.NewSource(int64(run * 31337)))
start := time.Now()
sols := solver.SolveHybrid(n, trip.RoomSize, trip.PreferNotMultiple, trip.NoPreferCost, constraints, params, rng)
elapsed := time.Since(start)
if len(sols) > 0 {
var assignments [][]int
for _, s := range sols {
assignments = append(assignments, s.Assignment)
}
results = append(results, runResult{sols[0].Score, assignments, elapsed})
}
}
label := fmt.Sprintf("hybrid restarts=%d steps=%d thigh=%.1f tlow=%.3f", nr, ns, *hybridTempHigh, *hybridTempLow)
printStats(label, results, *runs)
}
label := fmt.Sprintf("random=%d perturb=%d pmin=%d pmax=%d", nr, np, *perturbMin, *perturbMax)
printStats(label, results, *runs)
}
}
}

View File

@@ -1,7 +1,6 @@
package solver
import (
"math"
"math/rand"
"slices"
"strconv"
@@ -28,34 +27,6 @@ var DefaultParams = Params{
PerturbMax: 8,
}
type SAParams struct {
Restarts int
Steps int
TempHigh float64
TempLow float64
}
var DefaultSAParams = SAParams{
Restarts: 20,
Steps: 10000,
TempHigh: 5.0,
TempLow: 0.01,
}
type HybridParams struct {
SARestarts int
SASteps int
TempHigh float64
TempLow float64
}
var DefaultHybridParams = HybridParams{
SARestarts: 50,
SASteps: 5000,
TempHigh: 10.0,
TempLow: 0.1,
}
type Solution struct {
Assignment []int
Score int
@@ -251,14 +222,6 @@ func (s *solverState) score(assignment []int) int {
return sc
}
func (s *solverState) roomCounts(assignment []int) []int {
counts := make([]int, s.numRooms)
for _, room := range assignment {
counts[room]++
}
return counts
}
func (s *solverState) feasibleForGroup(assignment []int, groupRoot int, room int) bool {
for _, m := range s.groups[groupRoot] {
for _, partner := range s.mustApartFor[m] {
@@ -634,200 +597,6 @@ func (t *solutionTracker) add(a []int, s int) {
}
}
func Solve(n, roomSize, pnMultiple, npCost int, constraints []Constraint, params Params, rng *rand.Rand) []Solution {
if n == 0 {
return nil
}
st := newSolverState(n, roomSize, pnMultiple, npCost, constraints)
if st.hasHardConflict() {
return nil
}
assignment := make([]int, n)
if !st.initialPlacement(assignment) {
for i := range n {
assignment[i] = i % st.numRooms
}
}
initialAssignment := slices.Clone(assignment)
tracker := newTracker(assignment, st.score(assignment))
roomCount := func(a []int, room int) int {
c := 0
for _, r := range a {
if r == room {
c++
}
}
return c
}
feasible := func(a []int) bool {
for p := range st.mustApart {
if a[p[0]] == a[p[1]] {
return false
}
}
rc := map[int]int{}
for _, room := range a {
rc[room]++
}
for _, cnt := range rc {
if cnt > roomSize {
return false
}
}
return true
}
hillClimb := func(assignment []int) int {
currentScore := st.score(assignment)
for {
bestDelta := 0
bestMove := -1
bestTarget := -1
bestSwapJ := -1
for gi, gRoot := range st.uniqueGroups {
grp := st.groups[gRoot]
gRoom := assignment[grp[0]]
for room := range st.numRooms {
if room == gRoom {
continue
}
if roomCount(assignment, room)+len(grp) > roomSize {
continue
}
for _, m := range grp {
assignment[m] = room
}
if feasible(assignment) {
delta := st.score(assignment) - currentScore
if delta > bestDelta {
bestDelta = delta
bestMove = gi
bestTarget = room
bestSwapJ = -1
}
}
for _, m := range grp {
assignment[m] = gRoom
}
}
for gj := gi + 1; gj < len(st.uniqueGroups); gj++ {
grp2 := st.groups[st.uniqueGroups[gj]]
g2Room := assignment[grp2[0]]
if gRoom == g2Room {
continue
}
newGRoom := roomCount(assignment, gRoom) - len(grp) + len(grp2)
newG2Room := roomCount(assignment, g2Room) - len(grp2) + len(grp)
if newGRoom > roomSize || newG2Room > roomSize {
continue
}
for _, m := range grp {
assignment[m] = g2Room
}
for _, m := range grp2 {
assignment[m] = gRoom
}
if feasible(assignment) {
delta := st.score(assignment) - currentScore
if delta > bestDelta {
bestDelta = delta
bestMove = gi
bestTarget = -1
bestSwapJ = gj
}
}
for _, m := range grp {
assignment[m] = gRoom
}
for _, m := range grp2 {
assignment[m] = g2Room
}
}
}
if bestDelta <= 0 {
break
}
grp := st.groups[st.uniqueGroups[bestMove]]
gRoom := assignment[grp[0]]
if bestSwapJ < 0 {
for _, m := range grp {
assignment[m] = bestTarget
}
} else {
grp2 := st.groups[st.uniqueGroups[bestSwapJ]]
g2Room := assignment[grp2[0]]
for _, m := range grp {
assignment[m] = g2Room
}
for _, m := range grp2 {
assignment[m] = gRoom
}
}
currentScore += bestDelta
}
return currentScore
}
perturb := func(src []int, count int) {
copy(assignment, src)
indices := rng.Perm(len(st.uniqueGroups))
count = min(count, len(indices))
for _, gi := range indices[:count] {
grp := st.groups[st.uniqueGroups[gi]]
oldRoom := assignment[grp[0]]
rooms := rng.Perm(st.numRooms)
for _, room := range rooms {
if room == oldRoom {
continue
}
if roomCount(assignment, room)+len(grp) > roomSize {
continue
}
for _, m := range grp {
assignment[m] = room
}
if feasible(assignment) {
break
}
for _, m := range grp {
assignment[m] = oldRoom
}
}
}
}
copy(assignment, initialAssignment)
tracker.add(assignment, hillClimb(assignment))
for range params.NumRandom {
if st.randomPlacement(assignment, rng) {
tracker.add(assignment, hillClimb(assignment))
}
}
for range params.NumPerturb {
src := tracker.bestSolutions[rng.Intn(len(tracker.bestSolutions))]
perturb(src, params.PerturbMin+rng.Intn(params.PerturbMax-params.PerturbMin))
tracker.add(assignment, hillClimb(assignment))
}
results := make([]Solution, len(tracker.bestSolutions))
for i, sol := range tracker.bestSolutions {
results[i] = Solution{Assignment: sol, Score: tracker.bestScore}
}
return results
}
func SolveFast(n, roomSize, pnMultiple, npCost int, constraints []Constraint, params Params, rng *rand.Rand) []Solution {
if n == 0 {
return nil
@@ -926,448 +695,3 @@ func SolveFast(n, roomSize, pnMultiple, npCost int, constraints []Constraint, pa
return results
}
func SolveSA(n, roomSize, pnMultiple, npCost int, constraints []Constraint, params SAParams, rng *rand.Rand) []Solution {
if n == 0 {
return nil
}
st := newSolverState(n, roomSize, pnMultiple, npCost, constraints)
if st.hasHardConflict() {
return nil
}
assignment := make([]int, n)
if !st.initialPlacement(assignment) {
for i := range n {
assignment[i] = i % st.numRooms
}
}
tracker := newTracker(assignment, st.score(assignment))
counts := st.roomCounts(assignment)
tryMove := func(assignment []int, counts []int, rng *rand.Rand) (gi int, oldRoom int, newRoom int, swapGi int, ok bool) {
nGroups := len(st.uniqueGroups)
gi = rng.Intn(nGroups)
grp := st.groups[st.uniqueGroups[gi]]
oldRoom = assignment[grp[0]]
if rng.Intn(3) == 0 && nGroups > 1 {
swapGi = rng.Intn(nGroups - 1)
if swapGi >= gi {
swapGi++
}
grp2 := st.groups[st.uniqueGroups[swapGi]]
g2Room := assignment[grp2[0]]
if oldRoom == g2Room {
return 0, 0, 0, 0, false
}
newOldCount := counts[oldRoom] - len(grp) + len(grp2)
newG2Count := counts[g2Room] - len(grp2) + len(grp)
if newOldCount > roomSize || newG2Count > roomSize {
return 0, 0, 0, 0, false
}
for _, m := range grp {
assignment[m] = g2Room
}
for _, m := range grp2 {
assignment[m] = oldRoom
}
if !st.feasibleForGroup(assignment, st.uniqueGroups[gi], g2Room) ||
!st.feasibleForGroup(assignment, st.uniqueGroups[swapGi], oldRoom) {
for _, m := range grp {
assignment[m] = oldRoom
}
for _, m := range grp2 {
assignment[m] = g2Room
}
return 0, 0, 0, 0, false
}
for _, m := range grp {
assignment[m] = oldRoom
}
for _, m := range grp2 {
assignment[m] = g2Room
}
return gi, oldRoom, g2Room, swapGi, true
}
newRoom = rng.Intn(st.numRooms - 1)
if newRoom >= oldRoom {
newRoom++
}
if counts[newRoom]+len(grp) > roomSize {
return 0, 0, 0, 0, false
}
for _, m := range grp {
assignment[m] = newRoom
}
if !st.feasibleForGroup(assignment, st.uniqueGroups[gi], newRoom) {
for _, m := range grp {
assignment[m] = oldRoom
}
return 0, 0, 0, 0, false
}
for _, m := range grp {
assignment[m] = oldRoom
}
return gi, oldRoom, newRoom, -1, true
}
applyMove := func(assignment []int, counts []int, gi, oldRoom, newRoom, swapGi int) {
grp := st.groups[st.uniqueGroups[gi]]
if swapGi >= 0 {
grp2 := st.groups[st.uniqueGroups[swapGi]]
g2Room := assignment[grp2[0]]
counts[oldRoom] -= len(grp)
counts[g2Room] -= len(grp2)
for _, m := range grp {
assignment[m] = g2Room
}
for _, m := range grp2 {
assignment[m] = oldRoom
}
counts[g2Room] += len(grp)
counts[oldRoom] += len(grp2)
} else {
counts[oldRoom] -= len(grp)
for _, m := range grp {
assignment[m] = newRoom
}
counts[newRoom] += len(grp)
}
}
for restart := range params.Restarts {
if restart > 0 {
if !st.randomPlacement(assignment, rng) {
continue
}
counts = st.roomCounts(assignment)
}
currentScore := st.score(assignment)
for step := range params.Steps {
t := params.TempHigh * math.Pow(params.TempLow/params.TempHigh, float64(step)/float64(params.Steps-1))
gi, oldRoom, newRoom, swapGi, ok := tryMove(assignment, counts, rng)
if !ok {
continue
}
applyMove(assignment, counts, gi, oldRoom, newRoom, swapGi)
newScore := st.score(assignment)
delta := newScore - currentScore
if delta >= 0 || rng.Float64() < math.Exp(float64(delta)/t) {
currentScore = newScore
tracker.add(assignment, currentScore)
} else {
if swapGi >= 0 {
grp := st.groups[st.uniqueGroups[gi]]
grp2 := st.groups[st.uniqueGroups[swapGi]]
g2Room := assignment[grp2[0]]
counts[g2Room] -= len(grp2)
counts[oldRoom] -= len(grp)
for _, m := range grp {
assignment[m] = oldRoom
}
for _, m := range grp2 {
assignment[m] = g2Room
}
counts[oldRoom] += len(grp)
counts[g2Room] += len(grp2)
} else {
grp := st.groups[st.uniqueGroups[gi]]
counts[newRoom] -= len(grp)
for _, m := range grp {
assignment[m] = oldRoom
}
counts[oldRoom] += len(grp)
}
}
}
}
results := make([]Solution, len(tracker.bestSolutions))
for i, sol := range tracker.bestSolutions {
results[i] = Solution{Assignment: sol, Score: tracker.bestScore}
}
return results
}
func SolveHybrid(n, roomSize, pnMultiple, npCost int, constraints []Constraint, params HybridParams, rng *rand.Rand) []Solution {
if n == 0 {
return nil
}
st := newSolverState(n, roomSize, pnMultiple, npCost, constraints)
if st.hasHardConflict() {
return nil
}
numRooms := st.numRooms
roomCount := func(a []int, room int) int {
c := 0
for _, r := range a {
if r == room {
c++
}
}
return c
}
feasible := func(a []int) bool {
for p := range st.mustApart {
if a[p[0]] == a[p[1]] {
return false
}
}
rc := map[int]int{}
for _, room := range a {
rc[room]++
}
for _, cnt := range rc {
if cnt > roomSize {
return false
}
}
return true
}
hillClimb := func(assignment []int) int {
currentScore := st.score(assignment)
for {
bestDelta := 0
bestMove := -1
bestTarget := -1
bestSwapJ := -1
for gi, gRoot := range st.uniqueGroups {
grp := st.groups[gRoot]
gRoom := assignment[grp[0]]
for room := range numRooms {
if room == gRoom {
continue
}
if roomCount(assignment, room)+len(grp) > roomSize {
continue
}
for _, m := range grp {
assignment[m] = room
}
if feasible(assignment) {
delta := st.score(assignment) - currentScore
if delta > bestDelta {
bestDelta = delta
bestMove = gi
bestTarget = room
bestSwapJ = -1
}
}
for _, m := range grp {
assignment[m] = gRoom
}
}
for gj := gi + 1; gj < len(st.uniqueGroups); gj++ {
grp2 := st.groups[st.uniqueGroups[gj]]
g2Room := assignment[grp2[0]]
if gRoom == g2Room {
continue
}
newGRoom := roomCount(assignment, gRoom) - len(grp) + len(grp2)
newG2Room := roomCount(assignment, g2Room) - len(grp2) + len(grp)
if newGRoom > roomSize || newG2Room > roomSize {
continue
}
for _, m := range grp {
assignment[m] = g2Room
}
for _, m := range grp2 {
assignment[m] = gRoom
}
if feasible(assignment) {
delta := st.score(assignment) - currentScore
if delta > bestDelta {
bestDelta = delta
bestMove = gi
bestTarget = -1
bestSwapJ = gj
}
}
for _, m := range grp {
assignment[m] = gRoom
}
for _, m := range grp2 {
assignment[m] = g2Room
}
}
}
if bestDelta <= 0 {
break
}
grp := st.groups[st.uniqueGroups[bestMove]]
gRoom := assignment[grp[0]]
if bestSwapJ < 0 {
for _, m := range grp {
assignment[m] = bestTarget
}
} else {
grp2 := st.groups[st.uniqueGroups[bestSwapJ]]
g2Room := assignment[grp2[0]]
for _, m := range grp {
assignment[m] = g2Room
}
for _, m := range grp2 {
assignment[m] = gRoom
}
}
currentScore += bestDelta
}
return currentScore
}
assignment := make([]int, n)
if !st.initialPlacement(assignment) {
for i := range n {
assignment[i] = i % numRooms
}
}
tracker := newTracker(assignment, st.score(assignment))
tracker.add(assignment, hillClimb(assignment))
counts := make([]int, numRooms)
for restart := range params.SARestarts {
if restart == 0 {
copy(assignment, tracker.bestSolutions[0])
} else {
if !st.randomPlacement(assignment, rng) {
continue
}
}
for i := range counts {
counts[i] = 0
}
for _, room := range assignment {
counts[room]++
}
currentScore := st.score(assignment)
for step := range params.SASteps {
t := params.TempHigh * math.Pow(params.TempLow/params.TempHigh, float64(step)/float64(params.SASteps-1))
nGroups := len(st.uniqueGroups)
gi := rng.Intn(nGroups)
grp := st.groups[st.uniqueGroups[gi]]
oldRoom := assignment[grp[0]]
var newRoom int
swapGi := -1
moved := false
if rng.Intn(3) == 0 && nGroups > 1 {
swapGi = rng.Intn(nGroups - 1)
if swapGi >= gi {
swapGi++
}
grp2 := st.groups[st.uniqueGroups[swapGi]]
g2Room := assignment[grp2[0]]
if oldRoom != g2Room {
newOld := counts[oldRoom] - len(grp) + len(grp2)
newG2 := counts[g2Room] - len(grp2) + len(grp)
if newOld <= roomSize && newG2 <= roomSize {
for _, m := range grp {
assignment[m] = g2Room
}
for _, m := range grp2 {
assignment[m] = oldRoom
}
if st.feasibleForGroup(assignment, st.uniqueGroups[gi], g2Room) &&
st.feasibleForGroup(assignment, st.uniqueGroups[swapGi], oldRoom) {
newRoom = g2Room
moved = true
counts[oldRoom] = newOld
counts[g2Room] = newG2
} else {
for _, m := range grp {
assignment[m] = oldRoom
}
for _, m := range grp2 {
assignment[m] = g2Room
}
}
}
}
}
if !moved {
swapGi = -1
newRoom = rng.Intn(numRooms - 1)
if newRoom >= oldRoom {
newRoom++
}
if counts[newRoom]+len(grp) <= roomSize {
for _, m := range grp {
assignment[m] = newRoom
}
if st.feasibleForGroup(assignment, st.uniqueGroups[gi], newRoom) {
moved = true
counts[oldRoom] -= len(grp)
counts[newRoom] += len(grp)
} else {
for _, m := range grp {
assignment[m] = oldRoom
}
}
}
}
if !moved {
continue
}
newScore := st.score(assignment)
delta := newScore - currentScore
if delta >= 0 || rng.Float64() < math.Exp(float64(delta)/t) {
currentScore = newScore
} else {
if swapGi >= 0 {
grp2 := st.groups[st.uniqueGroups[swapGi]]
g2Room := assignment[grp2[0]]
for _, m := range grp {
assignment[m] = oldRoom
}
for _, m := range grp2 {
assignment[m] = g2Room
}
counts[oldRoom] = counts[oldRoom] - len(grp2) + len(grp)
counts[g2Room] = counts[g2Room] - len(grp) + len(grp2)
} else {
for _, m := range grp {
assignment[m] = oldRoom
}
counts[newRoom] -= len(grp)
counts[oldRoom] += len(grp)
}
}
}
tracker.add(assignment, hillClimb(assignment))
}
results := make([]Solution, len(tracker.bestSolutions))
for i, sol := range tracker.bestSolutions {
results[i] = Solution{Assignment: sol, Score: tracker.bestScore}
}
return results
}