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::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;
}
