void LKH::LKHAlg::GenerateCandidates(int MaxCandidates, GainType MaxAlpha,
int Symmetric)
{
Node *From, *To;
Candidate *NFrom, *NN;
int a, d, Count;
if (TraceLevel >= 2)
printff("Generating candidates ... ");
if (MaxAlpha < 0 || MaxAlpha > INT_MAX)
MaxAlpha = INT_MAX;
/* Initialize CandidateSet for each node */
FreeCandidateSets();
From = FirstNode;
do
From->Mark = 0;
while ((From = From->Suc) != FirstNode);
if (MaxCandidates > 0) {
do {
assert(From->CandidateSet =
(Candidate *) malloc((MaxCandidates + 1) *
sizeof(Candidate)));
From->CandidateSet[0].To = 0;
}
while ((From = From->Suc) != FirstNode);
} else {
AddTourCandidates();
do {
if (!From->CandidateSet)
eprintf("MAX_CANDIDATES = 0: No candidates");
} while ((From = From->Suc) != FirstNode);
return;
}
/* Loop for each node, From */
do {
NFrom = From->CandidateSet;
if (From != FirstNode) {
From->Beta = INT_MIN;
for (To = From; To->Dad != 0; To = To->Dad) {
To->Dad->Beta =
!FixedOrCommon(To, To->Dad) ?
Max(To->Beta, To->Cost) : To->Beta;
To->Dad->Mark = From;
}
}
Count = 0;
/* Loop for each node, To */
To = FirstNode;
do {
if (To == From)
continue;
d = c && !FixedOrCommon(From, To) ? (this->*c)(From, To) : (this->*D)(From, To);
if (From == FirstNode)
a = To == From->Dad ? 0 : d - From->NextCost;
else if (To == FirstNode)
a = From == To->Dad ? 0 : d - To->NextCost;
else {
if (To->Mark != From)
To->Beta =
!FixedOrCommon(To, To->Dad) ?
Max(To->Dad->Beta, To->Cost) : To->Dad->Beta;
a = d - To->Beta;
}
if (FixedOrCommon(From, To))
a = INT_MIN;
else {
if (From->FixedTo2 || To->FixedTo2 || Forbidden(From, To))
continue;
if (InInputTour(From, To)) {
a = 0;
if (c)
d = (this->*D)(From, To);
} else if (c) {
if (a > MaxAlpha ||
(Count == MaxCandidates &&
(a > (NFrom - 1)->Alpha ||
(a == (NFrom - 1)->Alpha
&& d >= (NFrom - 1)->Cost))))
continue;
if (To == From->Dad) {
d = From->Cost;
a = 0;
} else if (From == To->Dad) {
d = To->Cost;
a = 0;
} else {
a -= d;
a += (d = (this->*D)(From, To));
}
}
}
if (a <= MaxAlpha && IsPossibleCandidate(From, To)) {
/* Insert new candidate edge in From->CandidateSet */
NN = NFrom;
while (--NN >= From->CandidateSet) {
if (a > NN->Alpha || (a == NN->Alpha && d >= NN->Cost))
break;
*(NN + 1) = *NN;
}
NN++;
NN->To = To;
NN->Cost = d;
NN->Alpha = a;
if (Count < MaxCandidates) {
Count++;
NFrom++;
}
NFrom->To = 0;
}
}
while ((To = To->Suc) != FirstNode);
}
while ((From = From->Suc) != FirstNode);
AddTourCandidates();
if (Symmetric)
SymmetrizeCandidateSet();
if (TraceLevel >= 2)
printff("done\n");
}
static GainType BestKOptMoveRec(int k, GainType G0,LKH::LKHAlg *Alg)
{
LKH::LKHAlg::Candidate *Nt2;
LKH::LKHAlg::Node *t1, *t2, *t3, *t4;
GainType G1, G2, G3, Gain;
int X4, i;
int Breadth2 = 0;
t1 = (*t.get())[1];
t2 = (*t.get())[i = 2 * k - 2];
(*incl.get())[(*incl.get())[i] = i + 1] = i;
(*incl.get())[(*incl.get())[1] = i + 2] = 1;
/* Choose (t2,t3) as a candidate edge emanating from t2 */
for (Nt2 = t2->CandidateSet; (t3 = Nt2->To); Nt2++) {
if (t3 == t2->Pred || t3 == t2->Suc ||
((G1 = G0 - Nt2->Cost) <= 0 && Alg->GainCriterionUsed &&
Alg->ProblemType != LKH::HCP && Alg->ProblemType != LKH::HPP)
|| Added(t2, t3))
continue;
if (++Breadth2 > Alg->MaxBreadth)
break;
MarkAdded(t2, t3);
(*t.get())[2 * k - 1] = t3;
(*G.get())[2 * k - 2] = G1 + t3->Pi;
/* Choose t4 as one of t3's two neighbors on the tour */
for (X4 = 1; X4 <= 2; X4++) {
t4 = X4 == 1 ? (Alg->Reversed == (t3)->Parent->Reversed ? (t3)->Pred : (t3)->Suc) : (Alg->Reversed == (t3)->Parent->Reversed ? (t3)->Suc : (t3)->Pred);
if ((Fixed(t3, t4) || Alg->IsCommonEdge(t3, t4)) || Deleted(t3, t4))
continue;
(*t.get())[2 * k] = t4;
G2 = G1 + (Alg->*(Alg->C))(t3, t4);
G3 = MINUS_INFINITY;
if (t4 != t1 && !Alg->Forbidden(t4, t1) && !Added(t4, t1) &&
(!Alg->c || G2 - (Alg->*(Alg->c))(t4, t1) > 0) &&
(G3 = G2 - (Alg->*(Alg->C))(t4, t1)) > 0 && FeasibleKOptMove(k)) {
UnmarkAdded(t2, t3);
Alg->MakeKOptMove(k);
return G3;
}
if (Alg->Backtracking && !Alg->Excludable(t3, t4))
continue;
MarkDeleted(t3, t4);
(*G.get())[2 * k - 1] = G2 - t4->Pi;
if (k < *K) {
if ((Gain = BestKOptMoveRec(k + 1, G2,Alg)) > 0) {
UnmarkAdded(t2, t3);
UnmarkDeleted(t3, t4);
return Gain;
}
(*incl.get())[(*incl.get())[1] = 2 * k] = 1;
}
if (t4 != t1 && !Alg->Forbidden(t4, t1) &&
k + 1 < Alg->NonsequentialMoveType &&
Alg->PatchingC >= 2 && Alg->PatchingA >= 1 &&
(Alg->Swaps == 0 || Alg->SubsequentPatching)) {
if (G3 == MINUS_INFINITY)
G3 = G2 - (Alg->*(Alg->C))(t4, t1);
if ((Alg->PatchingCRestricted ? G3 > 0 && Alg->IsCandidate(t4, t1) :
Alg->PatchingCExtended ? G3 > 0
|| Alg->IsCandidate(t4, t1) : G3 > 0)
&& (Gain = Alg->PatchCycles(k, G3)) > 0) {
UnmarkAdded(t2, t3);
UnmarkDeleted(t3, t4);
return Gain;
}
}
UnmarkDeleted(t3, t4);
if (k == *K && t4 != t1 && t3 != t1 && G3 <= 0 &&
!Added(t4, t1) &&
(!Alg->GainCriterionUsed || G2 - Alg->Precision >= t4->Cost)) {
if (!Alg->Backtracking || Alg->Swaps > 0) {
if ((G2 > *BestG2 ||
(G2 == *BestG2 && !Near(t3, t4) &&
Near((*T.get())[2 * *K - 1], (*T.get())[2 * *K]))) &&
Alg->Swaps < Alg->MaxSwaps &&
Alg->Excludable(t3, t4) && !InInputTour(t3, t4)) {
if (Alg->RestrictedSearch && *K > 2 &&
Alg->ProblemType != LKH::HCP && Alg->ProblemType != LKH::HPP) {
/* Ignore the move if the gain does not vary */
(*G.get())[0] = (*G.get())[2 * *K - 2];
(*G.get())[1] = (*G.get())[2 * *K - 1];
for (i = 2 * *K - 3; i >= 2; i--)
if ((*G.get())[i] != (*G.get())[i % 2])
break;
if (i < 2)
continue;
}
if (FeasibleKOptMove(*K)) {
*BestG2 = G2;
memcpy(T.get() + 1, t.get() + 1, 2 * *K * sizeof(LKH::LKHAlg::Node *));
}
}
} else if (Alg->MaxSwaps > 0 && FeasibleKOptMove(*K)) {
LKH::LKHAlg::Node *SUCt1 = (Alg->Reversed == (t1)->Parent->Reversed ? (t1)->Suc : (t1)->Pred);
Alg->MakeKOptMove(*K);
for (i = 1; i < 2 * k; i += 2) {
Alg->Exclude((*t.get())[i], (*t.get())[i + 1]);
UnmarkDeleted((*t.get())[i], (*t.get())[i + 1]);
}
for (i = 2; i < 2 * k; i += 2)
UnmarkAdded((*t.get())[i], (*t.get())[i + 1]);
memcpy(tSaved.get() + 1, t.get() + 1, 2 * k * sizeof(LKH::LKHAlg::Node *));
while ((t4 = (Alg->*(Alg->BestSubsequentMove))(t1, t4, &G2, &Gain)));
if (Gain > 0) {
UnmarkAdded(t2, t3);
return Gain;
}
Alg->RestoreTour();
*K = k;
memcpy(t.get() + 1, tSaved.get() + 1, 2 * *K * sizeof(LKH::LKHAlg::Node *));
for (i = 1; i < 2 * *K - 2; i += 2)
MarkDeleted((*t.get())[i], (*t.get())[i + 1]);
for (i = 2; i < 2 * *K; i += 2)
MarkAdded((*t.get())[i], (*t.get())[i + 1]);
for (i = 2; i < 2 * *K; i += 2)
(*incl.get())[(*incl.get())[i] = i + 1] = i;
(*incl.get())[(*incl.get())[1] = 2 * *K] = 1;
if (SUCt1 != (Alg->Reversed == (t1)->Parent->Reversed ? (t1)->Suc : (t1)->Pred))
Alg->Reversed ^= 1;
(*T.get())[2 * *K] = 0;
}
}
}
UnmarkAdded(t2, t3);
if (t3 == t1)
continue;
/* Try to delete an added edge, (_,t3) or (t3,_) */
for (i = 2 * k - 4; i >= 2; i--) {
if (t3 == (*t.get())[i]) {
t4 = (*t.get())[i ^ 1];
if (t4 == t1 || Alg->Forbidden(t4, t1) || (Fixed(t3, t4) || Alg->IsCommonEdge(t3, t4)) ||
Added(t4, t1))
continue;
G2 = G1 + (Alg->*(Alg->C))(t3, t4);
if ((!Alg->c || G2 - (Alg->*(Alg->c))(t4, t1) > 0)
&& (Gain = G2 - (Alg->*(Alg->C))(t4, t1)) > 0) {
(*incl.get())[(*incl.get())[i ^ 1] = 1] = i ^ 1;
(*incl.get())[(*incl.get())[i] = 2 * k - 2] = i;
if (FeasibleKOptMove(k - 1)) {
Alg->MakeKOptMove(k - 1);
return Gain;
}
(*incl.get())[(*incl.get())[i ^ 1] = i] = i ^ 1;
}
}
}
(*incl.get())[1] = 2 * k;
(*incl.get())[2 * k - 2] = 2 * k - 1;
}
return 0;
}
Node *Best2OptMove(Node * t1, Node * t2, GainType * G0, GainType * Gain)
{
Node *t3, *t4, *T3 = 0, *T4 = 0;
Candidate *Nt2;
GainType G1, G2, BestG2 = MINUS_INFINITY;
int Breadth2 = 0;
if (SUC(t1) != t2)
Reversed ^= 1;
/*
* Determine (T3,T4) = (t3,t4)
* such that
*
* G4 = *G0 - C(t2,T3) + C(T3,T4)
*
* is maximum (= BestG2), and (T3,T4) has not previously been included.
* If during this process a legal move with *Gain > 0 is found, then make
* the move and exit Best2OptMove immediately
*/
/* Choose (t2,t3) as a candidate edge emanating from t2 */
for (Nt2 = t2->CandidateSet; (t3 = Nt2->To); Nt2++) {
if (t3 == t2->Pred || t3 == t2->Suc ||
((G1 = *G0 - Nt2->Cost) <= 0 && GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
/* Choose t4 (only one choice gives a closed tour) */
t4 = PRED(t3);
if (FixedOrCommon(t3, t4))
continue;
G2 = G1 + C(t3, t4);
if (!Forbidden(t4, t1) &&
(!c || G2 - c(t4, t1) > 0) && (*Gain = G2 - C(t4, t1)) > 0) {
Swap1(t1, t2, t3);
*G0 = G2;
return 0;
}
if (++Breadth2 > MaxBreadth)
break;
if (GainCriterionUsed && G2 - Precision < t4->Cost)
continue;
if (!Backtracking || Swaps > 0) {
if (G2 > BestG2 &&
Swaps < MaxSwaps &&
Excludable(t3, t4) && (!InInputTour(t3, t4)
|| !Near(t3, t4))) {
T3 = t3;
T4 = t4;
BestG2 = G2;
}
} else if (MaxSwaps > 0) {
GainType G = G2;
Node *t = t4;
Make2OptMove(t1, t2, t3, t4);
Exclude(t1, t2);
Exclude(t3, t4);
while ((t = BestSubsequentMove(t1, t, &G, Gain)));
if (*Gain > 0)
return 0;
RestoreTour();
if (t2 != SUC(t1))
Reversed ^= 1;
}
}
*Gain = 0;
if (T4) {
/* Make the best 2-opt move */
Swap1(t1, t2, T3);
Exclude(t1, t2);
Exclude(T3, T4);
*G0 = BestG2;
}
return T4;
}
LKH::LKHAlg::Node * LKH::LKHAlg::Best4OptMove(Node * t1, Node * t2, GainType * G0, GainType * Gain)
{
Node *t3, *t4, *t5, *t6 = 0, *t7, *t8 = 0,
*T3 = 0, *T4 = 0, *T5 = 0, *T6 = 0, *T7 = 0, *T8 = 0;
Candidate *Nt2, *Nt4, *Nt6;
GainType G1, G2, G3, G4, G5, G6, BestG6 = MINUS_INFINITY;
int Case6 = 0, Case8 = 0, BestCase8 = 0, X4, X6, X8;
int Breadth2 = 0, Breadth4, Breadth6;
*Gain = 0;
if (SUC(t1) != t2)
Reversed ^= 1;
/*
* Determine (T3,T4,T5,T6,T7,T8) = (t3,t4,t5,t6,t7,t8)
* such that
*
* G8 = *G0 - C(t2,T3) + C(T3,T4)
* - C(T4,T5) + C(T5,T6)
* - C(T6,T7) + C(T7,T8)
*
* is maximum (= BestG6), and (T7,T8) has not previously been included.
* If during this process a legal move with *Gain > 0 is found, then make
* the move and exit Best4OptMove immediately.
*/
/* Choose (t2,t3) as a candidate edge emanating from t2 */
for (Nt2 = t2->CandidateSet; (t3 = Nt2->To); Nt2++) {
if (t3 == t2->Pred || t3 == t2->Suc ||
((G1 = *G0 - Nt2->Cost) <= 0 && GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
if (++Breadth2 > MaxBreadth)
break;
/* Choose t4 as one of t3's two neighbors on the tour */
for (X4 = 1; X4 <= 2; X4++) {
t4 = X4 == 1 ? PRED(t3) : SUC(t3);
if (FixedOrCommon(t3, t4))
continue;
G2 = G1 + (this->*C)(t3, t4);
if (X4 == 1 &&
!Forbidden(t4, t1) &&
(!c || G2 - (this->*c)(t4, t1) > 0) && (*Gain = G2 - (this->*C)(t4, t1)) > 0)
{
Swap1(t1, t2, t3);
return 0;
}
if (Backtracking && !Excludable(t3, t4))
continue;
Breadth4 = 0;
/* Choose (t4,t5) as a candidate edge emanating from t4 */
for (Nt4 = t4->CandidateSet; (t5 = Nt4->To); Nt4++) {
if (t5 == t4->Pred || t5 == t4->Suc ||
((G3 = G2 - Nt4->Cost) <= 0 && GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
if (++Breadth4 > MaxBreadth)
break;
/* Choose t6 as one of t5's two neighbors on the tour */
for (X6 = 1; X6 <= 2; X6++) {
if (X4 == 1) {
if (X6 == 1) {
Case6 = 1 + !BETWEEN(t2, t5, t4);
t6 = Case6 == 1 ? SUC(t5) : PRED(t5);
} else {
t6 = t6 == t5->Pred ? t5->Suc : t5->Pred;
if ((t5 == t1 && t6 == t2) ||
(t5 == t2 && t6 == t1))
continue;
Case6 += 2;
}
} else if (BETWEEN(t2, t5, t3)) {
Case6 = 4 + X6;
t6 = X6 == 1 ? SUC(t5) : PRED(t5);
if (t6 == t1)
continue;
} else {
if (X6 == 2)
break;
Case6 = 7;
t6 = PRED(t5);
if (t6 == t2)
continue;
}
if (FixedOrCommon(t5, t6))
continue;
G4 = G3 + (this->*C)(t5, t6);
if ((Case6 <= 2 || Case6 == 5 || Case6 == 6) &&
!Forbidden(t6, t1) &&
(!c || G4 - (this->*c)(t6, t1) > 0) &&
(*Gain = G4 - (this->*C)(t6, t1)) > 0) {
Make3OptMove(t1, t2, t3, t4, t5, t6, Case6);
return 0;
}
if (Backtracking && !Excludable(t5, t6))
continue;
Breadth6 = 0;
/* Choose (t6,t7) as a candidate edge emanating from t6 */
for (Nt6 = t6->CandidateSet; (t7 = Nt6->To); Nt6++) {
if (t7 == t6->Pred || t7 == t6->Suc ||
(t6 == t2 && t7 == t3) ||
(t6 == t3 && t7 == t2) ||
((G5 = G4 - Nt6->Cost) <= 0 &&
GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
if (++Breadth6 > MaxBreadth)
break;
/* Choose t8 as one of t7's two neighbors on the tour */
for (X8 = 1; X8 <= 2; X8++) {
if (X8 == 1) {
Case8 = Case6;
t8 = 0;
switch (Case6) {
case 1:
t8 = BETWEEN(t2, t7,
t5) ? SUC(t7) : PRED(t7);
break;
case 2:
t8 = BETWEEN(t3, t7,
t6) ? SUC(t7) : PRED(t7);
break;
case 3:
if (BETWEEN(t5, t7, t4))
t8 = SUC(t7);
break;
case 4:
if (BETWEEN(t2, t7, t5))
t8 = BETWEEN(t2, t7,
t4) ? SUC(t7) :
PRED(t7);
break;
case 5:
t8 = PRED(t7);
break;
case 6:
t8 = BETWEEN(t2, t7,
t3) ? SUC(t7) : PRED(t7);
break;
case 7:
if (BETWEEN(t2, t7, t3))
t8 = SUC(t7);
break;
}
if (t8 == 0)
break;
} else {
if (Case6 != 3 && Case6 != 4 && Case6 != 7)
break;
t8 = t8 == t7->Pred ? t7->Suc : t7->Pred;
Case8 += 8;
}
if (t8 == t1 ||
(t7 == t3 && t8 == t4) ||
(t7 == t4 && t8 == t3))
continue;
if (FixedOrCommon(t7, t8))
continue;
G6 = G5 + (this->*C)(t7, t8);
if (t8 != t1 &&
!Forbidden(t8, t1) &&
(!c || G6 - (this->*c)(t8, t1) > 0) &&
(*Gain = G6 - (this->*C)(t8, t1)) > 0) {
Make4OptMove(t1, t2, t3, t4, t5, t6, t7,
t8, Case8);
return 0;
}
if (GainCriterionUsed &&
G6 - Precision < t8->Cost)
continue;
if (!Backtracking || Swaps > 0) {
if ((G6 > BestG6 ||
(G6 == BestG6 && !Near(t7, t8) &&
Near(T7, T8))) &&
Swaps < MaxSwaps &&
Excludable(t7, t8) &&
!InInputTour(t7, t8)) {
/* Ignore the move if the gain does
not vary */
if (RestrictedSearch &&
ProblemType != HCP &&
ProblemType != HPP &&
G2 - t4->Pi == G4 - t6->Pi &&
G4 - t6->Pi == G6 - t8->Pi &&
G3 + t5->Pi == G1 + t3->Pi &&
G5 + t7->Pi == G3 + t5->Pi)
continue;
T3 = t3;
T4 = t4;
T5 = t5;
T6 = t6;
T7 = t7;
T8 = t8;
BestCase8 = Case8;
BestG6 = G6;
}
} else if (MaxSwaps > 0) {
GainType G = G6;
Node *t = t8;
Make4OptMove(t1, t2, t3, t4, t5, t6, t7,
t8, Case8);
Exclude(t1, t2);
Exclude(t3, t4);
Exclude(t5, t6);
Exclude(t7, t8);
while ((t =
(this->*BestSubsequentMove)(t1, t, &G,
Gain)));
if (*Gain > 0)
return 0;
RestoreTour();
if (t2 != SUC(t1))
Reversed ^= 1;
}
}
}
}
}
}
}
*Gain = 0;
if (T8) {
/* Make the best 4-opt move */
Make4OptMove(t1, t2, T3, T4, T5, T6, T7, T8, BestCase8);
Exclude(t1, t2), Exclude(T3, T4);
Exclude(T5, T6);
Exclude(T7, T8);
*G0 = BestG6;
}
return T8;
}
Node *Best3OptMove(Node * t1, Node * t2, GainType * G0, GainType * Gain)
{
Node *t3, *t4, *t5, *t6, *T3 = 0, *T4 = 0, *T5 = 0, *T6 = 0;
Candidate *Nt2, *Nt4;
GainType G1, G2, G3, G4, BestG4 = MINUS_INFINITY;
int Case6, BestCase6 = 0, X4, X6;
int Breadth2 = 0, Breadth4;
if (SUC(t1) != t2)
Reversed ^= 1;
/*
* Determine (T3,T4,T5,T6) = (t3,t4,t5,t6)
* such that
*
* G4 = *G0 - C(t2,T3) + C(T3,T4)
* - C(T4,T5) + C(T5,T6)
*
* is maximum (= BestG4), and (T5,T6) has not previously been included.
* If during this process a legal move with *Gain > 0 is found, then make
* the move and exit Best3OptMove immediately.
*/
/* Choose (t2,t3) as a candidate edge emanating from t2 */
for (Nt2 = t2->CandidateSet; (t3 = Nt2->To); Nt2++) {
if (t3 == t2->Pred || t3 == t2->Suc ||
((G1 = *G0 - Nt2->Cost) <= 0 && GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
if (++Breadth2 > MaxBreadth)
break;
/* Choose t4 as one of t3's two neighbors on the tour */
for (X4 = 1; X4 <= 2; X4++) {
t4 = X4 == 1 ? PRED(t3) : SUC(t3);
if (FixedOrCommon(t3, t4))
continue;
G2 = G1 + C(t3, t4);
if (X4 == 1 &&
!Forbidden(t4, t1) &&
(!c || G2 - c(t4, t1) > 0) && (*Gain = G2 - C(t4, t1)) > 0)
{
Swap1(t1, t2, t3);
return 0;
}
if (Backtracking && !Excludable(t3, t4))
continue;
Breadth4 = 0;
/* Choose (t4,t5) as a candidate edge emanating from t4 */
for (Nt4 = t4->CandidateSet; (t5 = Nt4->To); Nt4++) {
if (t5 == t4->Pred || t5 == t4->Suc ||
((G3 = G2 - Nt4->Cost) <= 0 && GainCriterionUsed) ||
(X4 == 2 && !BETWEEN(t2, t5, t3)))
continue;
if (++Breadth4 > MaxBreadth)
break;
/* Choose t6 as one of t5's two neighbors on the tour */
for (X6 = 1; X6 <= X4; X6++) {
if (X4 == 1) {
Case6 = 1 + !BETWEEN(t2, t5, t4);
t6 = Case6 == 1 ? SUC(t5) : PRED(t5);
} else {
Case6 = 4 + X6;
t6 = X6 == 1 ? SUC(t5) : PRED(t5);
if (t6 == t1)
continue;
}
if (FixedOrCommon(t5, t6))
continue;
G4 = G3 + C(t5, t6);
if (!Forbidden(t6, t1) &&
(!c || G4 - c(t6, t1) > 0) &&
(*Gain = G4 - C(t6, t1)) > 0) {
Make3OptMove(t1, t2, t3, t4, t5, t6, Case6);
return 0;
}
if (GainCriterionUsed && G4 - Precision < t6->Cost)
continue;
if (!Backtracking || Swaps > 0) {
if (G4 > BestG4 &&
Swaps < MaxSwaps &&
Excludable(t5, t6) &&
(!InInputTour(t5, t6) || !Near(t5, t6))) {
/* Ignore the move if the gain does not vary */
if (RestrictedSearch &&
ProblemType != HCP &&
ProblemType != HPP &&
G2 - t4->Pi == G4 - t6->Pi &&
G3 + t5->Pi == G1 + t3->Pi)
continue;
T3 = t3;
T4 = t4;
T5 = t5;
T6 = t6;
BestCase6 = Case6;
BestG4 = G4;
}
} else if (MaxSwaps > 0) {
GainType G = G4;
Node *t = t6;
Make3OptMove(t1, t2, t3, t4, t5, t6, Case6);
Exclude(t1, t2);
Exclude(t3, t4);
Exclude(t5, t6);
while ((t = BestSubsequentMove(t1, t, &G, Gain)));
if (*Gain > 0)
return 0;
RestoreTour();
if (t2 != SUC(t1))
Reversed ^= 1;
}
}
}
}
}
*Gain = 0;
if (T6) {
/* Make the best 3-opt move */
Make3OptMove(t1, t2, T3, T4, T5, T6, BestCase6);
Exclude(t1, t2);
Exclude(T3, T4);
Exclude(T5, T6);
*G0 = BestG4;
}
return T6;
}
LKH::LKHAlg::Node * LKH::LKHAlg::Best5OptMove(Node * t1, Node * t2, GainType * G0, GainType * Gain)
{
Node *t3, *t4, *t5, *t6 = 0, *t7, *t8 = 0, *t9, *t10 = 0;
Node *T3 = 0, *T4 = 0, *T5 = 0, *T6 = 0, *T7 = 0, *T8 = 0, *T9 =
0, *T10 = 0;
Candidate *Nt2, *Nt4, *Nt6, *Nt8;
GainType G1, G2, G3, G4, G5, G6, G7, G8, BestG8 = MINUS_INFINITY;
int Case6 = 0, Case8 = 0, Case10 = 0, BestCase10 = 0, X4, X6, X8, X10,
BTW275 = 0, BTW674 = 0,
BTW571 = 0, BTW376 = 0, BTW574 = 0, BTW671 = 0,
BTW471 = 0, BTW673 = 0, BTW573 = 0, BTW273 = 0;
int Breadth2 = 0, Breadth4, Breadth6, Breadth8;
if (t2 != SUC(t1))
Reversed ^= 1;
/*
* Determine (T3,T4,T5,T6,T7,T8,T9,T10) = (t3,t4,t5,t6,t7,t8,t9,t10)
* such that
*
* G8 = *G0 - C(t2,T3) + C(T3,T4)
* - C(T4,T5) + C(T5,T6)
* - C(T6,T7) + C(T7,T8)
* - C(T8,T9) + C(T9,T10)
*
* is maximum (= BestG8), and (T9,T10) has not previously been included.
* If during this process a legal move with *Gain > 0 is found, then make
* the move and exit Best5OptMove immediately.
*/
/* Choose (t2,t3) as a candidate edge emanating from t2 */
for (Nt2 = t2->CandidateSet; (t3 = Nt2->To); Nt2++) {
if (t3 == t2->Pred || t3 == t2->Suc ||
((G1 = *G0 - Nt2->Cost) <= 0 && GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
if (++Breadth2 > MaxBreadth)
break;
/* Choose t4 as one of t3's two neighbors on the tour */
for (X4 = 1; X4 <= 2; X4++) {
t4 = X4 == 1 ? PRED(t3) : SUC(t3);
if (FixedOrCommon(t3, t4))
continue;
G2 = G1 + (this->*C)(t3, t4);
if (X4 == 1 &&
!Forbidden(t4, t1) &&
(!c || G2 - (this->*c)(t4, t1) > 0) && (*Gain = G2 - (this->*C)(t4, t1)) > 0)
{
Make2OptMove(t1, t2, t3, t4);
return 0;
}
if (Backtracking && !Excludable(t3, t4))
continue;
Breadth4 = 0;
/* Choose (t4,t5) as a candidate edge emanating from t4 */
for (Nt4 = t4->CandidateSet; (t5 = Nt4->To); Nt4++) {
if (t5 == t4->Pred || t5 == t4->Suc ||
((G3 = G2 - Nt4->Cost) <= 0 && GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
if (++Breadth4 > MaxBreadth)
break;
/* Choose t6 as one of t5's two neighbors on the tour */
for (X6 = 1; X6 <= 2; X6++) {
if (X4 == 1) {
if (X6 == 1) {
Case6 = 1 + !BETWEEN(t2, t5, t4);
t6 = Case6 == 1 ? SUC(t5) : PRED(t5);
} else {
t6 = t6 == t5->Pred ? t5->Suc : t5->Pred;
if ((t5 == t1 && t6 == t2) ||
(t5 == t2 && t6 == t1))
continue;
Case6 += 2;
}
} else if (BETWEEN(t2, t5, t3)) {
Case6 = 4 + X6;
t6 = X6 == 1 ? SUC(t5) : PRED(t5);
if (t6 == t1)
continue;
} else {
Case6 = 6 + X6;
t6 = X6 == 1 ? PRED(t5) : SUC(t5);
if (t6 == t2)
continue;
}
if (FixedOrCommon(t5, t6))
continue;
G4 = G3 + (this->*C)(t5, t6);
if ((Case6 <= 2 || Case6 == 5 || Case6 == 6) &&
!Forbidden(t6, t1) &&
(!c || G4 - (this->*c)(t6, t1) > 0) &&
(*Gain = G4 - (this->*C)(t6, t1)) > 0) {
Make3OptMove(t1, t2, t3, t4, t5, t6, Case6);
return 0;
}
if (Backtracking && !Excludable(t5, t6))
continue;
Breadth6 = 0;
/* Choose (t6,t7) as a candidate edge emanating from t6 */
for (Nt6 = t6->CandidateSet; (t7 = Nt6->To); Nt6++) {
if (t7 == t6->Pred || t7 == t6->Suc ||
(t6 == t2 && t7 == t3) ||
(t6 == t3 && t7 == t2) ||
((G5 = G4 - Nt6->Cost) <= 0 &&
GainCriterionUsed &&
ProblemType != HCP && ProblemType != HPP))
continue;
if (++Breadth6 > MaxBreadth)
break;
/* Choose t8 as one of t7's two neighbors on the tour */
for (X8 = 1; X8 <= 2; X8++) {
if (X8 == 1) {
Case8 = Case6;
switch (Case6) {
case 1:
if ((BTW275 = BETWEEN(t2, t7, t5)))
t8 = SUC(t7);
else {
t8 = PRED(t7);
BTW674 = BETWEEN(t6, t7, t4);
}
break;
case 2:
if ((BTW376 = BETWEEN(t3, t7, t6)))
t8 = SUC(t7);
else {
t8 = PRED(t7);
BTW571 = BETWEEN(t5, t7, t1);
}
break;
case 3:
t8 = SUC(t7);
BTW574 = BETWEEN(t5, t7, t4);
break;
case 4:
if ((BTW671 = BETWEEN(t6, t7, t1)))
t8 = PRED(t7);
else
t8 = BETWEEN(t2, t7,
t4) ? SUC(t7) :
PRED(t7);
break;
case 5:
t8 = PRED(t7);
BTW471 = BETWEEN(t4, t7, t1);
if (!BTW471)
BTW673 = BETWEEN(t6, t7, t3);
break;
case 6:
if ((BTW471 = BETWEEN(t4, t7, t1)))
t8 = PRED(t7);
else {
t8 = SUC(t7);
BTW573 = BETWEEN(t5, t7, t3);
}
break;
case 7:
case 8:
t8 = SUC(t7);
BTW273 = BETWEEN(t2, t7, t3);
break;
}
} else {
t8 = t8 == t7->Pred ? t7->Suc : t7->Pred;
Case8 += 8;
}
if ((t7 == t1 && t8 == t2) ||
(t7 == t2 && t8 == t1) ||
(t7 == t3 && t8 == t4) ||
(t7 == t4 && t8 == t3))
continue;
if (FixedOrCommon(t7, t8))
continue;
if (Case6 == 3 && !BTW574 &&
(X8 == 1) == BETWEEN(t3, t7, t1))
continue;
if (Case6 == 4 && BTW671 && X8 == 2)
break;
if (Case6 == 7 && !BTW273 &&
(X8 == 1) == BETWEEN(t5, t7, t1))
continue;
if (Case6 == 8 && !BTW273
&& !BETWEEN(t4, t7, t5))
break;
G6 = G5 + (this->*C)(t7, t8);
if (t8 != t1 &&
(Case6 == 3 ? BTW574 :
Case6 == 4 ? !BTW671 :
Case6 == 7 ? BTW273 :
Case6 != 8 && X8 == 1) &&
!Forbidden(t8, t1) &&
(!c || G6 - (this->*c)(t8, t1) > 0) &&
(*Gain = G6 - (this->*C)(t8, t1)) > 0) {
Make4OptMove(t1, t2, t3, t4, t5, t6, t7,
t8, Case8);
return 0;
}
if (Backtracking && !Excludable(t7, t8))
continue;
Breadth8 = 0;
/* Choose (t8,t9) as a candidate edge emanating
from t8 */
for (Nt8 = t8->CandidateSet; (t9 = Nt8->To);
Nt8++) {
if (t9 == t8->Pred || t9 == t8->Suc
|| t9 == t1 || (t8 == t2 && t9 == t3)
|| (t8 == t3 && t9 == t2) || (t8 == t4
&& t9 ==
t5)
|| (t8 == t5 && t9 == t4)
|| ((G7 = G6 - Nt8->Cost) <= 0
&& GainCriterionUsed
&& ProblemType != HCP
&& ProblemType != HPP))
continue;
if (++Breadth8 > MaxBreadth)
break;
/* Choose t10 as one of t9's two neighbors
on the tour */
for (X10 = 1; X10 <= 2; X10++) {
if (X10 == 1) {
t10 = 0;
switch (Case8) {
case 1:
t10 = (BTW275 ?
BETWEEN(t8, t9, t5)
|| BETWEEN(t3, t9,
t1) : BTW674
? BETWEEN(t7, t9,
t1) :
BETWEEN(t7, t9,
t5)) ? PRED(t9)
: SUC(t9);
Case10 = 22;
break;
case 2:
t10 = (BTW376 ?
BETWEEN(t8, t9, t4) :
BTW571 ?
BETWEEN(t7, t9, t1)
|| BETWEEN(t3, t9,
t6) :
BETWEEN(t7, t9,
t1)) ? PRED(t9)
: SUC(t9);
Case10 = 23;
break;
case 3:
if (BTW574) {
t10 = BETWEEN(t5, t9, t1) ?
PRED(t9) : SUC(t9);
Case10 = 24;
break;
}
if (!BETWEEN(t5, t9, t4))
break;
t10 = SUC(t9);
Case10 = 1;
break;
case 4:
if (BTW671) {
if (!BETWEEN(t2, t9, t5))
break;
t10 = SUC(t9);
Case10 = 2;
break;
}
t10 = BETWEEN(t6, t9, t4) ?
PRED(t9) : SUC(t9);
Case10 = 25;
break;
case 5:
t10 = (BTW471 ?
BETWEEN(t7, t9, t1) :
BTW673 ?
BETWEEN(t7, t9, t5) :
BETWEEN(t4, t9, t1)
|| BETWEEN(t7, t9,
t5)) ?
PRED(t9) : SUC(t9);
Case10 = 26;
break;
case 6:
t10 = (BTW471 ?
BETWEEN(t7, t9, t3) :
BTW573 ?
BETWEEN(t8, t9, t6) :
BETWEEN(t4, t9, t1)
|| BETWEEN(t8, t9,
t6)) ?
PRED(t9) : SUC(t9);
Case10 = 27;
break;
case 7:
if (BTW273) {
t10 = BETWEEN(t5, t9, t3) ?
PRED(t9) : SUC(t9);
Case10 = 28;
break;
}
if (!BETWEEN(t2, t9, t3))
break;
t10 = SUC(t9);
Case10 = 3;
break;
case 8:
if (BTW273) {
if (!BETWEEN(t4, t9, t5))
break;
Case10 = 4;
} else {
if (!BETWEEN(t2, t9, t3))
break;
Case10 = 5;
}
t10 = SUC(t9);
break;
case 9:
if (BTW275) {
if (!BETWEEN(t7, t9, t4))
break;
t10 = SUC(t9);
Case10 = 6;
break;
}
if (!BTW674) {
if (!BETWEEN(t2, t9, t7))
break;
t10 = SUC(t9);
Case10 = 7;
break;
}
if (!BETWEEN(t6, t9, t7))
break;
t10 = SUC(t9);
Case10 = 8;
break;
case 10:
if (BTW376) {
if (!BETWEEN(t7, t9, t6))
break;
t10 = SUC(t9);
Case10 = 9;
break;
}
if (BTW571) {
if (!BETWEEN(t2, t9, t7))
break;
t10 = SUC(t9);
Case10 = 10;
break;
}
if (!BETWEEN(t3, t9, t6) &&
!BETWEEN(t2, t9, t7))
break;
t10 = SUC(t9);
Case10 = 11;
break;
case 11:
if (BTW574) {
t10 = BETWEEN(t3, t9, t1) ?
PRED(t9) : SUC(t9);
Case10 = 29;
break;
}
if (!BETWEEN(t5, t9, t4))
break;
t10 = SUC(t9);
Case10 = 12;
break;
case 12:
t10 = BETWEEN(t3, t9, t1) ?
PRED(t9) : SUC(t9);
Case10 = 30;
break;
case 13:
if (BTW471) {
if (!BETWEEN(t2, t9, t7))
break;
t10 = SUC(t9);
Case10 = 13;
break;
}
if (BTW673) {
if (!BETWEEN(t6, t9, t7))
break;
t10 = SUC(t9);
Case10 = 14;
break;
}
if (!BETWEEN(t6, t9, t3) &&
!BETWEEN(t2, t9, t7))
break;
t10 = SUC(t9);
Case10 = 15;
break;
case 14:
if (BTW471) {
if (!BETWEEN(t2, t9, t7))
break;
t10 = SUC(t9);
Case10 = 16;
break;
}
if (BTW573) {
if (!BETWEEN(t7, t9, t3) &&
!BETWEEN(t2, t9, t6))
break;
t10 = SUC(t9);
Case10 = 17;
break;
}
if (!BETWEEN(t7, t9, t6))
break;
t10 = SUC(t9);
Case10 = 18;
break;
case 15:
if (BTW273) {
t10 = BETWEEN(t5, t9, t1) ?
PRED(t9) : SUC(t9);
Case10 = 31;
break;
}
if (!BETWEEN(t2, t9, t3))
break;
t10 = SUC(t9);
Case10 = 19;
break;
case 16:
if (BTW273) {
if (!BETWEEN(t4, t9, t5))
break;
Case10 = 20;
} else {
if (!BETWEEN(t2, t9, t3))
break;
Case10 = 21;
}
t10 = SUC(t9);
break;
}
if (!t10)
break;
} else {
if (Case10 >= 22)
continue;
Case10 += 31;
t10 =
t10 ==
t9->Pred ? t9->Suc : t9->Pred;
}
if (t10 == t1 ||
(t9 == t3 && t10 == t4) ||
(t9 == t4 && t10 == t3) ||
(t9 == t5 && t10 == t6) ||
(t9 == t6 && t10 == t5))
continue;
if (FixedOrCommon(t9, t10))
continue;
G8 = G7 + (this->*C)(t9, t10);
if (!Forbidden(t10, t1) &&
(!c || G8 - (this->*c)(t10, t1) > 0) &&
(*Gain = G8 - (this->*C)(t10, t1)) > 0) {
Make5OptMove(t1, t2, t3, t4, t5,
t6, t7, t8, t9, t10,
Case10);
return 0;
}
if (GainCriterionUsed &&
G8 - Precision < t10->Cost)
continue;
if (!Backtracking || Swaps > 0) {
if ((G8 > BestG8 ||
(G8 == BestG8 && !Near(t9, t10)
&& Near(T9, T10)))
&& Swaps < MaxSwaps
&& Excludable(t9, t10)
&& !InInputTour(t9, t10)) {
/* Ignore the move if the gain does
not vary */
if (RestrictedSearch &&
ProblemType != HCP &&
ProblemType != HPP &&
G2 - t4->Pi == G4 - t6->Pi &&
G4 - t6->Pi == G6 - t8->Pi &&
G6 - t8->Pi == G8 - t10->Pi &&
G3 + t5->Pi == G1 + t3->Pi &&
G5 + t7->Pi == G3 + t5->Pi &&
G7 + t9->Pi == G5 + t7->Pi)
continue;
T3 = t3;
T4 = t4;
T5 = t5;
T6 = t6;
T7 = t7;
T8 = t8;
T9 = t9;
T10 = t10;
BestCase10 = Case10;
BestG8 = G8;
}
} else if (MaxSwaps > 0) {
GainType G = G8;
Node *t = t10;
Make5OptMove(t1, t2, t3, t4, t5,
t6, t7, t8, t9, t10,
Case10);
Exclude(t1, t2);
Exclude(t3, t4);
Exclude(t5, t6);
Exclude(t7, t8);
Exclude(t9, t10);
while ((t =
(this->*BestSubsequentMove)(t1, t,
&G,
Gain)));
if (*Gain > 0)
return 0;
RestoreTour();
if (t2 != SUC(t1))
Reversed ^= 1;
}
}
}
}
}
}
}
}
}
*Gain = 0;
if (T10) {
/* Make the best 5-opt move */
Make5OptMove(t1, t2, T3, T4, T5, T6, T7, T8, T9, T10, BestCase10);
Exclude(t1, t2);
Exclude(T3, T4);
Exclude(T5, T6);
Exclude(T7, T8);
Exclude(T9, T10);
*G0 = BestG8;
}
return T10;
}
