0
2
0
58
24
... | ... |
@@ -170,13 +170,13 @@ |
170 | 170 |
CostVector _pi; |
171 | 171 |
ValueVector _excess; |
172 | 172 |
IntVector _excess_nodes; |
173 | 173 |
IntVector _deficit_nodes; |
174 | 174 |
|
175 | 175 |
Value _delta; |
176 |
int |
|
176 |
int _factor; |
|
177 | 177 |
IntVector _pred; |
178 | 178 |
|
179 | 179 |
public: |
180 | 180 |
|
181 | 181 |
/// \brief Constant for infinite upper bounds (capacities). |
182 | 182 |
/// |
... | ... |
@@ -510,32 +510,32 @@ |
510 | 510 |
/// |
511 | 511 |
/// This function can be called more than once. All the parameters |
512 | 512 |
/// that have been given are kept for the next call, unless |
513 | 513 |
/// \ref reset() is called, thus only the modified parameters |
514 | 514 |
/// have to be set again. See \ref reset() for examples. |
515 | 515 |
/// However the underlying digraph must not be modified after this |
516 |
/// class have been constructed, since it copies the |
|
516 |
/// class have been constructed, since it copies and extends the graph. |
|
517 | 517 |
/// |
518 |
/// \param scaling Enable or disable capacity scaling. |
|
519 |
/// If the maximum upper bound and/or the amount of total supply |
|
520 |
/// is rather small, the algorithm could be slightly faster without |
|
521 |
/// scaling. |
|
518 |
/// \param factor The capacity scaling factor. It must be larger than |
|
519 |
/// one to use scaling. If it is less or equal to one, then scaling |
|
520 |
/// will be disabled. |
|
522 | 521 |
/// |
523 | 522 |
/// \return \c INFEASIBLE if no feasible flow exists, |
524 | 523 |
/// \n \c OPTIMAL if the problem has optimal solution |
525 | 524 |
/// (i.e. it is feasible and bounded), and the algorithm has found |
526 | 525 |
/// optimal flow and node potentials (primal and dual solutions), |
527 | 526 |
/// \n \c UNBOUNDED if the digraph contains an arc of negative cost |
528 | 527 |
/// and infinite upper bound. It means that the objective function |
529 | 528 |
/// is unbounded on that arc, however note that it could actually be |
530 | 529 |
/// bounded over the feasible flows, but this algroithm cannot handle |
531 | 530 |
/// these cases. |
532 | 531 |
/// |
533 | 532 |
/// \see ProblemType |
534 |
ProblemType run(bool scaling = true) { |
|
535 |
ProblemType pt = init(scaling); |
|
533 |
ProblemType run(int factor = 4) { |
|
534 |
_factor = factor; |
|
535 |
ProblemType pt = init(); |
|
536 | 536 |
if (pt != OPTIMAL) return pt; |
537 | 537 |
return start(); |
538 | 538 |
} |
539 | 539 |
|
540 | 540 |
/// \brief Reset all the parameters that have been given before. |
541 | 541 |
/// |
... | ... |
@@ -543,13 +543,13 @@ |
543 | 543 |
/// before using functions \ref lowerMap(), \ref upperMap(), |
544 | 544 |
/// \ref costMap(), \ref supplyMap(), \ref stSupply(). |
545 | 545 |
/// |
546 | 546 |
/// It is useful for multiple run() calls. If this function is not |
547 | 547 |
/// used, all the parameters given before are kept for the next |
548 | 548 |
/// \ref run() call. |
549 |
/// However the underlying digraph must not be modified after this |
|
549 |
/// However, the underlying digraph must not be modified after this |
|
550 | 550 |
/// class have been constructed, since it copies and extends the graph. |
551 | 551 |
/// |
552 | 552 |
/// For example, |
553 | 553 |
/// \code |
554 | 554 |
/// CapacityScaling<ListDigraph> cs(graph); |
555 | 555 |
/// |
... | ... |
@@ -674,13 +674,13 @@ |
674 | 674 |
|
675 | 675 |
/// @} |
676 | 676 |
|
677 | 677 |
private: |
678 | 678 |
|
679 | 679 |
// Initialize the algorithm |
680 |
ProblemType init( |
|
680 |
ProblemType init() { |
|
681 | 681 |
if (_node_num == 0) return INFEASIBLE; |
682 | 682 |
|
683 | 683 |
// Check the sum of supply values |
684 | 684 |
_sum_supply = 0; |
685 | 685 |
for (int i = 0; i != _root; ++i) { |
686 | 686 |
_sum_supply += _supply[i]; |
... | ... |
@@ -755,27 +755,25 @@ |
755 | 755 |
_cost[a] = 0; |
756 | 756 |
_cost[_reverse[a]] = 0; |
757 | 757 |
} |
758 | 758 |
} |
759 | 759 |
|
760 | 760 |
// Initialize delta value |
761 |
if ( |
|
761 |
if (_factor > 1) { |
|
762 | 762 |
// With scaling |
763 | 763 |
Value max_sup = 0, max_dem = 0; |
764 | 764 |
for (int i = 0; i != _node_num; ++i) { |
765 | 765 |
if ( _excess[i] > max_sup) max_sup = _excess[i]; |
766 | 766 |
if (-_excess[i] > max_dem) max_dem = -_excess[i]; |
767 | 767 |
} |
768 | 768 |
Value max_cap = 0; |
769 | 769 |
for (int j = 0; j != _res_arc_num; ++j) { |
770 | 770 |
if (_res_cap[j] > max_cap) max_cap = _res_cap[j]; |
771 | 771 |
} |
772 | 772 |
max_sup = std::min(std::min(max_sup, max_dem), max_cap); |
773 |
_phase_num = 0; |
|
774 |
for (_delta = 1; 2 * _delta <= max_sup; _delta *= 2) |
|
775 |
|
|
773 |
for (_delta = 1; 2 * _delta <= max_sup; _delta *= 2) ; |
|
776 | 774 |
} else { |
777 | 775 |
// Without scaling |
778 | 776 |
_delta = 1; |
779 | 777 |
} |
780 | 778 |
|
781 | 779 |
return OPTIMAL; |
... | ... |
@@ -808,14 +806,12 @@ |
808 | 806 |
} |
809 | 807 |
|
810 | 808 |
// Execute the capacity scaling algorithm |
811 | 809 |
ProblemType startWithScaling() { |
812 | 810 |
// Perform capacity scaling phases |
813 | 811 |
int s, t; |
814 |
int phase_cnt = 0; |
|
815 |
int factor = 4; |
|
816 | 812 |
ResidualDijkstra _dijkstra(*this); |
817 | 813 |
while (true) { |
818 | 814 |
// Saturate all arcs not satisfying the optimality condition |
819 | 815 |
for (int u = 0; u != _node_num; ++u) { |
820 | 816 |
for (int a = _first_out[u]; a != _first_out[u+1]; ++a) { |
821 | 817 |
int v = _target[a]; |
... | ... |
@@ -884,14 +880,13 @@ |
884 | 880 |
_excess[t] += d; |
885 | 881 |
|
886 | 882 |
if (_excess[s] < _delta) ++next_node; |
887 | 883 |
} |
888 | 884 |
|
889 | 885 |
if (_delta == 1) break; |
890 |
if (++phase_cnt == _phase_num / 4) factor = 2; |
|
891 |
_delta = _delta <= factor ? 1 : _delta / factor; |
|
886 |
_delta = _delta <= _factor ? 1 : _delta / _factor; |
|
892 | 887 |
} |
893 | 888 |
|
894 | 889 |
return OPTIMAL; |
895 | 890 |
} |
896 | 891 |
|
897 | 892 |
// Execute the successive shortest path algorithm |
... | ... |
@@ -107,12 +107,16 @@ |
107 | 107 |
/// algorithm. By default it is the same as \c V. |
108 | 108 |
/// |
109 | 109 |
/// \warning Both value types must be signed and all input data must |
110 | 110 |
/// be integer. |
111 | 111 |
/// \warning This algorithm does not support negative costs for such |
112 | 112 |
/// arcs that have infinite upper bound. |
113 |
/// |
|
114 |
/// \note %CostScaling provides three different internal methods, |
|
115 |
/// from which the most efficient one is used by default. |
|
116 |
/// For more information, see \ref Method. |
|
113 | 117 |
#ifdef DOXYGEN |
114 | 118 |
template <typename GR, typename V, typename C, typename TR> |
115 | 119 |
#else |
116 | 120 |
template < typename GR, typename V = int, typename C = V, |
117 | 121 |
typename TR = CostScalingDefaultTraits<GR, V, C> > |
118 | 122 |
#endif |
... | ... |
@@ -156,12 +160,39 @@ |
156 | 160 |
/// on that arc, however note that it could actually be bounded |
157 | 161 |
/// over the feasible flows, but this algroithm cannot handle |
158 | 162 |
/// these cases. |
159 | 163 |
UNBOUNDED |
160 | 164 |
}; |
161 | 165 |
|
166 |
/// \brief Constants for selecting the internal method. |
|
167 |
/// |
|
168 |
/// Enum type containing constants for selecting the internal method |
|
169 |
/// for the \ref run() function. |
|
170 |
/// |
|
171 |
/// \ref CostScaling provides three internal methods that differ mainly |
|
172 |
/// in their base operations, which are used in conjunction with the |
|
173 |
/// relabel operation. |
|
174 |
/// By default, the so called \ref PARTIAL_AUGMENT |
|
175 |
/// "Partial Augment-Relabel" method is used, which proved to be |
|
176 |
/// the most efficient and the most robust on various test inputs. |
|
177 |
/// However, the other methods can be selected using the \ref run() |
|
178 |
/// function with the proper parameter. |
|
179 |
enum Method { |
|
180 |
/// Local push operations are used, i.e. flow is moved only on one |
|
181 |
/// admissible arc at once. |
|
182 |
PUSH, |
|
183 |
/// Augment operations are used, i.e. flow is moved on admissible |
|
184 |
/// paths from a node with excess to a node with deficit. |
|
185 |
AUGMENT, |
|
186 |
/// Partial augment operations are used, i.e. flow is moved on |
|
187 |
/// admissible paths started from a node with excess, but the |
|
188 |
/// lengths of these paths are limited. This method can be viewed |
|
189 |
/// as a combined version of the previous two operations. |
|
190 |
PARTIAL_AUGMENT |
|
191 |
}; |
|
192 |
|
|
162 | 193 |
private: |
163 | 194 |
|
164 | 195 |
TEMPLATE_DIGRAPH_TYPEDEFS(GR); |
165 | 196 |
|
166 | 197 |
typedef std::vector<int> IntVector; |
167 | 198 |
typedef std::vector<char> BoolVector; |
... | ... |
@@ -502,35 +533,35 @@ |
502 | 533 |
/// \endcode |
503 | 534 |
/// |
504 | 535 |
/// This function can be called more than once. All the parameters |
505 | 536 |
/// that have been given are kept for the next call, unless |
506 | 537 |
/// \ref reset() is called, thus only the modified parameters |
507 | 538 |
/// have to be set again. See \ref reset() for examples. |
508 |
/// However the underlying digraph must not be modified after this |
|
509 |
/// class have been constructed, since it copies the digraph. |
|
539 |
/// However, the underlying digraph must not be modified after this |
|
540 |
/// class have been constructed, since it copies and extends the graph. |
|
510 | 541 |
/// |
511 |
/// \param partial_augment By default the algorithm performs |
|
512 |
/// partial augment and relabel operations in the cost scaling |
|
513 |
/// phases. Set this parameter to \c false for using local push and |
|
514 |
/// relabel operations instead. |
|
542 |
/// \param method The internal method that will be used in the |
|
543 |
/// algorithm. For more information, see \ref Method. |
|
544 |
/// \param factor The cost scaling factor. It must be larger than one. |
|
515 | 545 |
/// |
516 | 546 |
/// \return \c INFEASIBLE if no feasible flow exists, |
517 | 547 |
/// \n \c OPTIMAL if the problem has optimal solution |
518 | 548 |
/// (i.e. it is feasible and bounded), and the algorithm has found |
519 | 549 |
/// optimal flow and node potentials (primal and dual solutions), |
520 | 550 |
/// \n \c UNBOUNDED if the digraph contains an arc of negative cost |
521 | 551 |
/// and infinite upper bound. It means that the objective function |
522 | 552 |
/// is unbounded on that arc, however note that it could actually be |
523 | 553 |
/// bounded over the feasible flows, but this algroithm cannot handle |
524 | 554 |
/// these cases. |
525 | 555 |
/// |
526 |
/// \see ProblemType |
|
527 |
ProblemType run(bool partial_augment = true) { |
|
556 |
/// \see ProblemType, Method |
|
557 |
ProblemType run(Method method = PARTIAL_AUGMENT, int factor = 8) { |
|
558 |
_alpha = factor; |
|
528 | 559 |
ProblemType pt = init(); |
529 | 560 |
if (pt != OPTIMAL) return pt; |
530 |
start( |
|
561 |
start(method); |
|
531 | 562 |
return OPTIMAL; |
532 | 563 |
} |
533 | 564 |
|
534 | 565 |
/// \brief Reset all the parameters that have been given before. |
535 | 566 |
/// |
536 | 567 |
/// This function resets all the paramaters that have been given |
... | ... |
@@ -678,15 +709,12 @@ |
678 | 709 |
private: |
679 | 710 |
|
680 | 711 |
// Initialize the algorithm |
681 | 712 |
ProblemType init() { |
682 | 713 |
if (_res_node_num == 0) return INFEASIBLE; |
683 | 714 |
|
684 |
// Scaling factor |
|
685 |
_alpha = 8; |
|
686 |
|
|
687 | 715 |
// Check the sum of supply values |
688 | 716 |
_sum_supply = 0; |
689 | 717 |
for (int i = 0; i != _root; ++i) { |
690 | 718 |
_sum_supply += _supply[i]; |
691 | 719 |
} |
692 | 720 |
if (_sum_supply > 0) return INFEASIBLE; |
... | ... |
@@ -814,18 +842,27 @@ |
814 | 842 |
} |
815 | 843 |
|
816 | 844 |
return OPTIMAL; |
817 | 845 |
} |
818 | 846 |
|
819 | 847 |
// Execute the algorithm and transform the results |
820 |
void start( |
|
848 |
void start(Method method) { |
|
849 |
// Maximum path length for partial augment |
|
850 |
const int MAX_PATH_LENGTH = 4; |
|
851 |
|
|
821 | 852 |
// Execute the algorithm |
822 |
if (partial_augment) { |
|
823 |
startPartialAugment(); |
|
824 |
} else { |
|
825 |
startPushRelabel(); |
|
853 |
switch (method) { |
|
854 |
case PUSH: |
|
855 |
startPush(); |
|
856 |
break; |
|
857 |
case AUGMENT: |
|
858 |
startAugment(); |
|
859 |
break; |
|
860 |
case PARTIAL_AUGMENT: |
|
861 |
startAugment(MAX_PATH_LENGTH); |
|
862 |
break; |
|
826 | 863 |
} |
827 | 864 |
|
828 | 865 |
// Compute node potentials for the original costs |
829 | 866 |
_arc_vec.clear(); |
830 | 867 |
_cost_vec.clear(); |
831 | 868 |
for (int j = 0; j != _res_arc_num; ++j) { |
... | ... |
@@ -848,20 +885,17 @@ |
848 | 885 |
for (int j = 0; j != limit; ++j) { |
849 | 886 |
if (!_forward[j]) _res_cap[j] += _lower[j]; |
850 | 887 |
} |
851 | 888 |
} |
852 | 889 |
} |
853 | 890 |
|
854 |
/// Execute the algorithm performing partial augmentation and |
|
855 |
/// relabel operations |
|
856 |
|
|
891 |
/// Execute the algorithm performing augment and relabel operations |
|
892 |
void startAugment(int max_length = std::numeric_limits<int>::max()) { |
|
857 | 893 |
// Paramters for heuristics |
858 | 894 |
const int BF_HEURISTIC_EPSILON_BOUND = 1000; |
859 | 895 |
const int BF_HEURISTIC_BOUND_FACTOR = 3; |
860 |
// Maximum augment path length |
|
861 |
const int MAX_PATH_LENGTH = 4; |
|
862 | 896 |
|
863 | 897 |
// Perform cost scaling phases |
864 | 898 |
IntVector pred_arc(_res_node_num); |
865 | 899 |
std::vector<int> path_nodes; |
866 | 900 |
for ( ; _epsilon >= 1; _epsilon = _epsilon < _alpha && _epsilon > 1 ? |
867 | 901 |
1 : _epsilon / _alpha ) |
... | ... |
@@ -922,13 +956,13 @@ |
922 | 956 |
path_nodes.clear(); |
923 | 957 |
path_nodes.push_back(start); |
924 | 958 |
|
925 | 959 |
// Find an augmenting path from the start node |
926 | 960 |
int tip = start; |
927 | 961 |
while (_excess[tip] >= 0 && |
928 |
int(path_nodes.size()) <= |
|
962 |
int(path_nodes.size()) <= max_length) { |
|
929 | 963 |
int u; |
930 | 964 |
LargeCost min_red_cost, rc; |
931 | 965 |
int last_out = _sum_supply < 0 ? |
932 | 966 |
_first_out[tip+1] : _first_out[tip+1] - 1; |
933 | 967 |
for (int a = _next_out[tip]; a != last_out; ++a) { |
934 | 968 |
if (_res_cap[a] > 0 && |
... | ... |
@@ -981,13 +1015,13 @@ |
981 | 1015 |
} |
982 | 1016 |
} |
983 | 1017 |
} |
984 | 1018 |
} |
985 | 1019 |
|
986 | 1020 |
/// Execute the algorithm performing push and relabel operations |
987 |
void |
|
1021 |
void startPush() { |
|
988 | 1022 |
// Paramters for heuristics |
989 | 1023 |
const int BF_HEURISTIC_EPSILON_BOUND = 1000; |
990 | 1024 |
const int BF_HEURISTIC_BOUND_FACTOR = 3; |
991 | 1025 |
|
992 | 1026 |
// Perform cost scaling phases |
993 | 1027 |
BoolVector hyper(_res_node_num, false); |
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