0
4
0
| ... | ... |
@@ -131,15 +131,16 @@ |
| 131 | 131 |
|
| 132 | 132 |
private: |
| 133 | 133 |
|
| 134 | 134 |
TEMPLATE_DIGRAPH_TYPEDEFS(GR); |
| 135 | 135 |
|
| 136 | 136 |
typedef std::vector<int> IntVector; |
| 137 |
typedef std::vector<char> BoolVector; |
|
| 138 | 137 |
typedef std::vector<Value> ValueVector; |
| 139 | 138 |
typedef std::vector<Cost> CostVector; |
| 139 |
typedef std::vector<char> BoolVector; |
|
| 140 |
// Note: vector<char> is used instead of vector<bool> for efficiency reasons |
|
| 140 | 141 |
|
| 141 | 142 |
private: |
| 142 | 143 |
|
| 143 | 144 |
// Data related to the underlying digraph |
| 144 | 145 |
const GR &_graph; |
| 145 | 146 |
int _node_num; |
| ... | ... |
@@ -761,21 +762,21 @@ |
| 761 | 762 |
} |
| 762 | 763 |
} |
| 763 | 764 |
|
| 764 | 765 |
// Initialize delta value |
| 765 | 766 |
if (_factor > 1) {
|
| 766 | 767 |
// With scaling |
| 767 |
Value max_sup = 0, max_dem = 0; |
|
| 768 |
for (int i = 0; i != _node_num; ++i) {
|
|
| 768 |
Value max_sup = 0, max_dem = 0, max_cap = 0; |
|
| 769 |
for (int i = 0; i != _root; ++i) {
|
|
| 769 | 770 |
Value ex = _excess[i]; |
| 770 | 771 |
if ( ex > max_sup) max_sup = ex; |
| 771 | 772 |
if (-ex > max_dem) max_dem = -ex; |
| 772 |
} |
|
| 773 |
Value max_cap = 0; |
|
| 774 |
for (int j = 0; j != _res_arc_num; ++j) {
|
|
| 775 |
if (_res_cap[j] > max_cap) max_cap = _res_cap[j]; |
|
| 773 |
int last_out = _first_out[i+1] - 1; |
|
| 774 |
for (int j = _first_out[i]; j != last_out; ++j) {
|
|
| 775 |
if (_res_cap[j] > max_cap) max_cap = _res_cap[j]; |
|
| 776 |
} |
|
| 776 | 777 |
} |
| 777 | 778 |
max_sup = std::min(std::min(max_sup, max_dem), max_cap); |
| 778 | 779 |
for (_delta = 1; 2 * _delta <= max_sup; _delta *= 2) ; |
| 779 | 780 |
} else {
|
| 780 | 781 |
// Without scaling |
| 781 | 782 |
_delta = 1; |
| ... | ... |
@@ -194,16 +194,17 @@ |
| 194 | 194 |
|
| 195 | 195 |
private: |
| 196 | 196 |
|
| 197 | 197 |
TEMPLATE_DIGRAPH_TYPEDEFS(GR); |
| 198 | 198 |
|
| 199 | 199 |
typedef std::vector<int> IntVector; |
| 200 |
typedef std::vector<char> BoolVector; |
|
| 201 | 200 |
typedef std::vector<Value> ValueVector; |
| 202 | 201 |
typedef std::vector<Cost> CostVector; |
| 203 | 202 |
typedef std::vector<LargeCost> LargeCostVector; |
| 203 |
typedef std::vector<char> BoolVector; |
|
| 204 |
// Note: vector<char> is used instead of vector<bool> for efficiency reasons |
|
| 204 | 205 |
|
| 205 | 206 |
private: |
| 206 | 207 |
|
| 207 | 208 |
template <typename KT, typename VT> |
| 208 | 209 |
class StaticVectorMap {
|
| 209 | 210 |
public: |
| ... | ... |
@@ -241,12 +242,13 @@ |
| 241 | 242 |
int _res_arc_num; |
| 242 | 243 |
int _root; |
| 243 | 244 |
|
| 244 | 245 |
// Parameters of the problem |
| 245 | 246 |
bool _have_lower; |
| 246 | 247 |
Value _sum_supply; |
| 248 |
int _sup_node_num; |
|
| 247 | 249 |
|
| 248 | 250 |
// Data structures for storing the digraph |
| 249 | 251 |
IntNodeMap _node_id; |
| 250 | 252 |
IntArcMap _arc_idf; |
| 251 | 253 |
IntArcMap _arc_idb; |
| 252 | 254 |
IntVector _first_out; |
| ... | ... |
@@ -269,12 +271,18 @@ |
| 269 | 271 |
std::deque<int> _active_nodes; |
| 270 | 272 |
|
| 271 | 273 |
// Data for scaling |
| 272 | 274 |
LargeCost _epsilon; |
| 273 | 275 |
int _alpha; |
| 274 | 276 |
|
| 277 |
IntVector _buckets; |
|
| 278 |
IntVector _bucket_next; |
|
| 279 |
IntVector _bucket_prev; |
|
| 280 |
IntVector _rank; |
|
| 281 |
int _max_rank; |
|
| 282 |
|
|
| 275 | 283 |
// Data for a StaticDigraph structure |
| 276 | 284 |
typedef std::pair<int, int> IntPair; |
| 277 | 285 |
StaticDigraph _sgr; |
| 278 | 286 |
std::vector<IntPair> _arc_vec; |
| 279 | 287 |
std::vector<LargeCost> _cost_vec; |
| 280 | 288 |
LargeCostArcMap _cost_map; |
| ... | ... |
@@ -799,12 +807,17 @@ |
| 799 | 807 |
} else {
|
| 800 | 808 |
for (ArcIt a(_graph); a != INVALID; ++a) {
|
| 801 | 809 |
cap[a] = _upper[_arc_idf[a]]; |
| 802 | 810 |
} |
| 803 | 811 |
} |
| 804 | 812 |
|
| 813 |
_sup_node_num = 0; |
|
| 814 |
for (NodeIt n(_graph); n != INVALID; ++n) {
|
|
| 815 |
if (sup[n] > 0) ++_sup_node_num; |
|
| 816 |
} |
|
| 817 |
|
|
| 805 | 818 |
// Find a feasible flow using Circulation |
| 806 | 819 |
Circulation<Digraph, ConstMap<Arc, Value>, ValueArcMap, ValueNodeMap> |
| 807 | 820 |
circ(_graph, low, cap, sup); |
| 808 | 821 |
if (!circ.flowMap(flow).run()) return INFEASIBLE; |
| 809 | 822 |
|
| 810 | 823 |
// Set residual capacities and handle GEQ supply type |
| ... | ... |
@@ -833,13 +846,13 @@ |
| 833 | 846 |
Value fa = flow[a]; |
| 834 | 847 |
_res_cap[_arc_idf[a]] = cap[a] - fa; |
| 835 | 848 |
_res_cap[_arc_idb[a]] = fa; |
| 836 | 849 |
} |
| 837 | 850 |
for (int a = _first_out[_root]; a != _res_arc_num; ++a) {
|
| 838 | 851 |
int ra = _reverse[a]; |
| 839 |
_res_cap[a] = |
|
| 852 |
_res_cap[a] = 0; |
|
| 840 | 853 |
_res_cap[ra] = 0; |
| 841 | 854 |
_cost[a] = 0; |
| 842 | 855 |
_cost[ra] = 0; |
| 843 | 856 |
} |
| 844 | 857 |
} |
| 845 | 858 |
|
| ... | ... |
@@ -847,13 +860,20 @@ |
| 847 | 860 |
} |
| 848 | 861 |
|
| 849 | 862 |
// Execute the algorithm and transform the results |
| 850 | 863 |
void start(Method method) {
|
| 851 | 864 |
// Maximum path length for partial augment |
| 852 | 865 |
const int MAX_PATH_LENGTH = 4; |
| 853 |
|
|
| 866 |
|
|
| 867 |
// Initialize data structures for buckets |
|
| 868 |
_max_rank = _alpha * _res_node_num; |
|
| 869 |
_buckets.resize(_max_rank); |
|
| 870 |
_bucket_next.resize(_res_node_num + 1); |
|
| 871 |
_bucket_prev.resize(_res_node_num + 1); |
|
| 872 |
_rank.resize(_res_node_num + 1); |
|
| 873 |
|
|
| 854 | 874 |
// Execute the algorithm |
| 855 | 875 |
switch (method) {
|
| 856 | 876 |
case PUSH: |
| 857 | 877 |
startPush(); |
| 858 | 878 |
break; |
| 859 | 879 |
case AUGMENT: |
| ... | ... |
@@ -886,237 +906,325 @@ |
| 886 | 906 |
int limit = _first_out[_root]; |
| 887 | 907 |
for (int j = 0; j != limit; ++j) {
|
| 888 | 908 |
if (!_forward[j]) _res_cap[j] += _lower[j]; |
| 889 | 909 |
} |
| 890 | 910 |
} |
| 891 | 911 |
} |
| 912 |
|
|
| 913 |
// Initialize a cost scaling phase |
|
| 914 |
void initPhase() {
|
|
| 915 |
// Saturate arcs not satisfying the optimality condition |
|
| 916 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 917 |
int last_out = _first_out[u+1]; |
|
| 918 |
LargeCost pi_u = _pi[u]; |
|
| 919 |
for (int a = _first_out[u]; a != last_out; ++a) {
|
|
| 920 |
int v = _target[a]; |
|
| 921 |
if (_res_cap[a] > 0 && _cost[a] + pi_u - _pi[v] < 0) {
|
|
| 922 |
Value delta = _res_cap[a]; |
|
| 923 |
_excess[u] -= delta; |
|
| 924 |
_excess[v] += delta; |
|
| 925 |
_res_cap[a] = 0; |
|
| 926 |
_res_cap[_reverse[a]] += delta; |
|
| 927 |
} |
|
| 928 |
} |
|
| 929 |
} |
|
| 930 |
|
|
| 931 |
// Find active nodes (i.e. nodes with positive excess) |
|
| 932 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 933 |
if (_excess[u] > 0) _active_nodes.push_back(u); |
|
| 934 |
} |
|
| 935 |
|
|
| 936 |
// Initialize the next arcs |
|
| 937 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 938 |
_next_out[u] = _first_out[u]; |
|
| 939 |
} |
|
| 940 |
} |
|
| 941 |
|
|
| 942 |
// Early termination heuristic |
|
| 943 |
bool earlyTermination() {
|
|
| 944 |
const double EARLY_TERM_FACTOR = 3.0; |
|
| 945 |
|
|
| 946 |
// Build a static residual graph |
|
| 947 |
_arc_vec.clear(); |
|
| 948 |
_cost_vec.clear(); |
|
| 949 |
for (int j = 0; j != _res_arc_num; ++j) {
|
|
| 950 |
if (_res_cap[j] > 0) {
|
|
| 951 |
_arc_vec.push_back(IntPair(_source[j], _target[j])); |
|
| 952 |
_cost_vec.push_back(_cost[j] + 1); |
|
| 953 |
} |
|
| 954 |
} |
|
| 955 |
_sgr.build(_res_node_num, _arc_vec.begin(), _arc_vec.end()); |
|
| 956 |
|
|
| 957 |
// Run Bellman-Ford algorithm to check if the current flow is optimal |
|
| 958 |
BellmanFord<StaticDigraph, LargeCostArcMap> bf(_sgr, _cost_map); |
|
| 959 |
bf.init(0); |
|
| 960 |
bool done = false; |
|
| 961 |
int K = int(EARLY_TERM_FACTOR * std::sqrt(double(_res_node_num))); |
|
| 962 |
for (int i = 0; i < K && !done; ++i) {
|
|
| 963 |
done = bf.processNextWeakRound(); |
|
| 964 |
} |
|
| 965 |
return done; |
|
| 966 |
} |
|
| 967 |
|
|
| 968 |
// Global potential update heuristic |
|
| 969 |
void globalUpdate() {
|
|
| 970 |
int bucket_end = _root + 1; |
|
| 971 |
|
|
| 972 |
// Initialize buckets |
|
| 973 |
for (int r = 0; r != _max_rank; ++r) {
|
|
| 974 |
_buckets[r] = bucket_end; |
|
| 975 |
} |
|
| 976 |
Value total_excess = 0; |
|
| 977 |
for (int i = 0; i != _res_node_num; ++i) {
|
|
| 978 |
if (_excess[i] < 0) {
|
|
| 979 |
_rank[i] = 0; |
|
| 980 |
_bucket_next[i] = _buckets[0]; |
|
| 981 |
_bucket_prev[_buckets[0]] = i; |
|
| 982 |
_buckets[0] = i; |
|
| 983 |
} else {
|
|
| 984 |
total_excess += _excess[i]; |
|
| 985 |
_rank[i] = _max_rank; |
|
| 986 |
} |
|
| 987 |
} |
|
| 988 |
if (total_excess == 0) return; |
|
| 989 |
|
|
| 990 |
// Search the buckets |
|
| 991 |
int r = 0; |
|
| 992 |
for ( ; r != _max_rank; ++r) {
|
|
| 993 |
while (_buckets[r] != bucket_end) {
|
|
| 994 |
// Remove the first node from the current bucket |
|
| 995 |
int u = _buckets[r]; |
|
| 996 |
_buckets[r] = _bucket_next[u]; |
|
| 997 |
|
|
| 998 |
// Search the incomming arcs of u |
|
| 999 |
LargeCost pi_u = _pi[u]; |
|
| 1000 |
int last_out = _first_out[u+1]; |
|
| 1001 |
for (int a = _first_out[u]; a != last_out; ++a) {
|
|
| 1002 |
int ra = _reverse[a]; |
|
| 1003 |
if (_res_cap[ra] > 0) {
|
|
| 1004 |
int v = _source[ra]; |
|
| 1005 |
int old_rank_v = _rank[v]; |
|
| 1006 |
if (r < old_rank_v) {
|
|
| 1007 |
// Compute the new rank of v |
|
| 1008 |
LargeCost nrc = (_cost[ra] + _pi[v] - pi_u) / _epsilon; |
|
| 1009 |
int new_rank_v = old_rank_v; |
|
| 1010 |
if (nrc < LargeCost(_max_rank)) |
|
| 1011 |
new_rank_v = r + 1 + int(nrc); |
|
| 1012 |
|
|
| 1013 |
// Change the rank of v |
|
| 1014 |
if (new_rank_v < old_rank_v) {
|
|
| 1015 |
_rank[v] = new_rank_v; |
|
| 1016 |
_next_out[v] = _first_out[v]; |
|
| 1017 |
|
|
| 1018 |
// Remove v from its old bucket |
|
| 1019 |
if (old_rank_v < _max_rank) {
|
|
| 1020 |
if (_buckets[old_rank_v] == v) {
|
|
| 1021 |
_buckets[old_rank_v] = _bucket_next[v]; |
|
| 1022 |
} else {
|
|
| 1023 |
_bucket_next[_bucket_prev[v]] = _bucket_next[v]; |
|
| 1024 |
_bucket_prev[_bucket_next[v]] = _bucket_prev[v]; |
|
| 1025 |
} |
|
| 1026 |
} |
|
| 1027 |
|
|
| 1028 |
// Insert v to its new bucket |
|
| 1029 |
_bucket_next[v] = _buckets[new_rank_v]; |
|
| 1030 |
_bucket_prev[_buckets[new_rank_v]] = v; |
|
| 1031 |
_buckets[new_rank_v] = v; |
|
| 1032 |
} |
|
| 1033 |
} |
|
| 1034 |
} |
|
| 1035 |
} |
|
| 1036 |
|
|
| 1037 |
// Finish search if there are no more active nodes |
|
| 1038 |
if (_excess[u] > 0) {
|
|
| 1039 |
total_excess -= _excess[u]; |
|
| 1040 |
if (total_excess <= 0) break; |
|
| 1041 |
} |
|
| 1042 |
} |
|
| 1043 |
if (total_excess <= 0) break; |
|
| 1044 |
} |
|
| 1045 |
|
|
| 1046 |
// Relabel nodes |
|
| 1047 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 1048 |
int k = std::min(_rank[u], r); |
|
| 1049 |
if (k > 0) {
|
|
| 1050 |
_pi[u] -= _epsilon * k; |
|
| 1051 |
_next_out[u] = _first_out[u]; |
|
| 1052 |
} |
|
| 1053 |
} |
|
| 1054 |
} |
|
| 892 | 1055 |
|
| 893 | 1056 |
/// Execute the algorithm performing augment and relabel operations |
| 894 | 1057 |
void startAugment(int max_length = std::numeric_limits<int>::max()) {
|
| 895 | 1058 |
// Paramters for heuristics |
| 896 |
const int BF_HEURISTIC_EPSILON_BOUND = 1000; |
|
| 897 |
const int BF_HEURISTIC_BOUND_FACTOR = 3; |
|
| 1059 |
const int EARLY_TERM_EPSILON_LIMIT = 1000; |
|
| 1060 |
const double GLOBAL_UPDATE_FACTOR = 3.0; |
|
| 898 | 1061 |
|
| 1062 |
const int global_update_freq = int(GLOBAL_UPDATE_FACTOR * |
|
| 1063 |
(_res_node_num + _sup_node_num * _sup_node_num)); |
|
| 1064 |
int next_update_limit = global_update_freq; |
|
| 1065 |
|
|
| 1066 |
int relabel_cnt = 0; |
|
| 1067 |
|
|
| 899 | 1068 |
// Perform cost scaling phases |
| 900 |
IntVector pred_arc(_res_node_num); |
|
| 901 |
std::vector<int> path_nodes; |
|
| 1069 |
std::vector<int> path; |
|
| 902 | 1070 |
for ( ; _epsilon >= 1; _epsilon = _epsilon < _alpha && _epsilon > 1 ? |
| 903 | 1071 |
1 : _epsilon / _alpha ) |
| 904 | 1072 |
{
|
| 905 |
// "Early Termination" heuristic: use Bellman-Ford algorithm |
|
| 906 |
// to check if the current flow is optimal |
|
| 907 |
if (_epsilon <= BF_HEURISTIC_EPSILON_BOUND) {
|
|
| 908 |
_arc_vec.clear(); |
|
| 909 |
_cost_vec.clear(); |
|
| 910 |
for (int j = 0; j != _res_arc_num; ++j) {
|
|
| 911 |
if (_res_cap[j] > 0) {
|
|
| 912 |
_arc_vec.push_back(IntPair(_source[j], _target[j])); |
|
| 913 |
_cost_vec.push_back(_cost[j] + 1); |
|
| 914 |
} |
|
| 915 |
} |
|
| 916 |
_sgr.build(_res_node_num, _arc_vec.begin(), _arc_vec.end()); |
|
| 917 |
|
|
| 918 |
BellmanFord<StaticDigraph, LargeCostArcMap> bf(_sgr, _cost_map); |
|
| 919 |
bf.init(0); |
|
| 920 |
bool done = false; |
|
| 921 |
int K = int(BF_HEURISTIC_BOUND_FACTOR * sqrt(_res_node_num)); |
|
| 922 |
for (int i = 0; i < K && !done; ++i) |
|
| 923 |
done = bf.processNextWeakRound(); |
|
| 924 |
if (done) break; |
|
| 925 |
} |
|
| 926 |
|
|
| 927 |
// Saturate arcs not satisfying the optimality condition |
|
| 928 |
for (int a = 0; a != _res_arc_num; ++a) {
|
|
| 929 |
if (_res_cap[a] > 0 && |
|
| 930 |
_cost[a] + _pi[_source[a]] - _pi[_target[a]] < 0) {
|
|
| 931 |
Value delta = _res_cap[a]; |
|
| 932 |
_excess[_source[a]] -= delta; |
|
| 933 |
_excess[_target[a]] += delta; |
|
| 934 |
_res_cap[a] = 0; |
|
| 935 |
_res_cap[_reverse[a]] += delta; |
|
| 936 |
} |
|
| 1073 |
// Early termination heuristic |
|
| 1074 |
if (_epsilon <= EARLY_TERM_EPSILON_LIMIT) {
|
|
| 1075 |
if (earlyTermination()) break; |
|
| 937 | 1076 |
} |
| 938 | 1077 |
|
| 939 |
// Find active nodes (i.e. nodes with positive excess) |
|
| 940 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 941 |
if (_excess[u] > 0) _active_nodes.push_back(u); |
|
| 942 |
} |
|
| 943 |
|
|
| 944 |
// Initialize the next arcs |
|
| 945 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 946 |
_next_out[u] = _first_out[u]; |
|
| 947 |
} |
|
| 948 |
|
|
| 1078 |
// Initialize current phase |
|
| 1079 |
initPhase(); |
|
| 1080 |
|
|
| 949 | 1081 |
// Perform partial augment and relabel operations |
| 950 | 1082 |
while (true) {
|
| 951 | 1083 |
// Select an active node (FIFO selection) |
| 952 | 1084 |
while (_active_nodes.size() > 0 && |
| 953 | 1085 |
_excess[_active_nodes.front()] <= 0) {
|
| 954 | 1086 |
_active_nodes.pop_front(); |
| 955 | 1087 |
} |
| 956 | 1088 |
if (_active_nodes.size() == 0) break; |
| 957 | 1089 |
int start = _active_nodes.front(); |
| 958 |
path_nodes.clear(); |
|
| 959 |
path_nodes.push_back(start); |
|
| 960 | 1090 |
|
| 961 | 1091 |
// Find an augmenting path from the start node |
| 1092 |
path.clear(); |
|
| 962 | 1093 |
int tip = start; |
| 963 |
while (_excess[tip] >= 0 && |
|
| 964 |
int(path_nodes.size()) <= max_length) {
|
|
| 1094 |
while (_excess[tip] >= 0 && int(path.size()) < max_length) {
|
|
| 965 | 1095 |
int u; |
| 966 |
LargeCost min_red_cost, rc; |
|
| 967 |
int last_out = _sum_supply < 0 ? |
|
| 968 |
|
|
| 1096 |
LargeCost min_red_cost, rc, pi_tip = _pi[tip]; |
|
| 1097 |
int last_out = _first_out[tip+1]; |
|
| 969 | 1098 |
for (int a = _next_out[tip]; a != last_out; ++a) {
|
| 970 |
if (_res_cap[a] > 0 && |
|
| 971 |
_cost[a] + _pi[_source[a]] - _pi[_target[a]] < 0) {
|
|
| 972 |
u = _target[a]; |
|
| 973 |
pred_arc[u] = a; |
|
| 1099 |
u = _target[a]; |
|
| 1100 |
if (_res_cap[a] > 0 && _cost[a] + pi_tip - _pi[u] < 0) {
|
|
| 1101 |
path.push_back(a); |
|
| 974 | 1102 |
_next_out[tip] = a; |
| 975 | 1103 |
tip = u; |
| 976 |
path_nodes.push_back(tip); |
|
| 977 | 1104 |
goto next_step; |
| 978 | 1105 |
} |
| 979 | 1106 |
} |
| 980 | 1107 |
|
| 981 | 1108 |
// Relabel tip node |
| 982 |
min_red_cost = std::numeric_limits<LargeCost>::max() |
|
| 1109 |
min_red_cost = std::numeric_limits<LargeCost>::max(); |
|
| 1110 |
if (tip != start) {
|
|
| 1111 |
int ra = _reverse[path.back()]; |
|
| 1112 |
min_red_cost = _cost[ra] + pi_tip - _pi[_target[ra]]; |
|
| 1113 |
} |
|
| 983 | 1114 |
for (int a = _first_out[tip]; a != last_out; ++a) {
|
| 984 |
rc = _cost[a] + |
|
| 1115 |
rc = _cost[a] + pi_tip - _pi[_target[a]]; |
|
| 985 | 1116 |
if (_res_cap[a] > 0 && rc < min_red_cost) {
|
| 986 | 1117 |
min_red_cost = rc; |
| 987 | 1118 |
} |
| 988 | 1119 |
} |
| 989 | 1120 |
_pi[tip] -= min_red_cost + _epsilon; |
| 990 |
|
|
| 991 |
// Reset the next arc of tip |
|
| 992 | 1121 |
_next_out[tip] = _first_out[tip]; |
| 1122 |
++relabel_cnt; |
|
| 993 | 1123 |
|
| 994 | 1124 |
// Step back |
| 995 | 1125 |
if (tip != start) {
|
| 996 |
path_nodes.pop_back(); |
|
| 997 |
tip = path_nodes.back(); |
|
| 1126 |
tip = _source[path.back()]; |
|
| 1127 |
path.pop_back(); |
|
| 998 | 1128 |
} |
| 999 | 1129 |
|
| 1000 | 1130 |
next_step: ; |
| 1001 | 1131 |
} |
| 1002 | 1132 |
|
| 1003 | 1133 |
// Augment along the found path (as much flow as possible) |
| 1004 | 1134 |
Value delta; |
| 1005 |
int u, v = path_nodes.front(), pa; |
|
| 1006 |
for (int i = 1; i < int(path_nodes.size()); ++i) {
|
|
| 1135 |
int pa, u, v = start; |
|
| 1136 |
for (int i = 0; i != int(path.size()); ++i) {
|
|
| 1137 |
pa = path[i]; |
|
| 1007 | 1138 |
u = v; |
| 1008 |
v = path_nodes[i]; |
|
| 1009 |
pa = pred_arc[v]; |
|
| 1139 |
v = _target[pa]; |
|
| 1010 | 1140 |
delta = std::min(_res_cap[pa], _excess[u]); |
| 1011 | 1141 |
_res_cap[pa] -= delta; |
| 1012 | 1142 |
_res_cap[_reverse[pa]] += delta; |
| 1013 | 1143 |
_excess[u] -= delta; |
| 1014 | 1144 |
_excess[v] += delta; |
| 1015 | 1145 |
if (_excess[v] > 0 && _excess[v] <= delta) |
| 1016 | 1146 |
_active_nodes.push_back(v); |
| 1017 | 1147 |
} |
| 1148 |
|
|
| 1149 |
// Global update heuristic |
|
| 1150 |
if (relabel_cnt >= next_update_limit) {
|
|
| 1151 |
globalUpdate(); |
|
| 1152 |
next_update_limit += global_update_freq; |
|
| 1153 |
} |
|
| 1018 | 1154 |
} |
| 1019 | 1155 |
} |
| 1020 | 1156 |
} |
| 1021 | 1157 |
|
| 1022 | 1158 |
/// Execute the algorithm performing push and relabel operations |
| 1023 | 1159 |
void startPush() {
|
| 1024 | 1160 |
// Paramters for heuristics |
| 1025 |
const int BF_HEURISTIC_EPSILON_BOUND = 1000; |
|
| 1026 |
const int BF_HEURISTIC_BOUND_FACTOR = 3; |
|
| 1161 |
const int EARLY_TERM_EPSILON_LIMIT = 1000; |
|
| 1162 |
const double GLOBAL_UPDATE_FACTOR = 2.0; |
|
| 1027 | 1163 |
|
| 1164 |
const int global_update_freq = int(GLOBAL_UPDATE_FACTOR * |
|
| 1165 |
(_res_node_num + _sup_node_num * _sup_node_num)); |
|
| 1166 |
int next_update_limit = global_update_freq; |
|
| 1167 |
|
|
| 1168 |
int relabel_cnt = 0; |
|
| 1169 |
|
|
| 1028 | 1170 |
// Perform cost scaling phases |
| 1029 | 1171 |
BoolVector hyper(_res_node_num, false); |
| 1172 |
LargeCostVector hyper_cost(_res_node_num); |
|
| 1030 | 1173 |
for ( ; _epsilon >= 1; _epsilon = _epsilon < _alpha && _epsilon > 1 ? |
| 1031 | 1174 |
1 : _epsilon / _alpha ) |
| 1032 | 1175 |
{
|
| 1033 |
// "Early Termination" heuristic: use Bellman-Ford algorithm |
|
| 1034 |
// to check if the current flow is optimal |
|
| 1035 |
if (_epsilon <= BF_HEURISTIC_EPSILON_BOUND) {
|
|
| 1036 |
_arc_vec.clear(); |
|
| 1037 |
_cost_vec.clear(); |
|
| 1038 |
for (int j = 0; j != _res_arc_num; ++j) {
|
|
| 1039 |
if (_res_cap[j] > 0) {
|
|
| 1040 |
_arc_vec.push_back(IntPair(_source[j], _target[j])); |
|
| 1041 |
_cost_vec.push_back(_cost[j] + 1); |
|
| 1042 |
} |
|
| 1043 |
} |
|
| 1044 |
_sgr.build(_res_node_num, _arc_vec.begin(), _arc_vec.end()); |
|
| 1045 |
|
|
| 1046 |
BellmanFord<StaticDigraph, LargeCostArcMap> bf(_sgr, _cost_map); |
|
| 1047 |
bf.init(0); |
|
| 1048 |
bool done = false; |
|
| 1049 |
int K = int(BF_HEURISTIC_BOUND_FACTOR * sqrt(_res_node_num)); |
|
| 1050 |
for (int i = 0; i < K && !done; ++i) |
|
| 1051 |
done = bf.processNextWeakRound(); |
|
| 1052 |
if (done) break; |
|
| 1176 |
// Early termination heuristic |
|
| 1177 |
if (_epsilon <= EARLY_TERM_EPSILON_LIMIT) {
|
|
| 1178 |
if (earlyTermination()) break; |
|
| 1053 | 1179 |
} |
| 1054 |
|
|
| 1055 |
// Saturate arcs not satisfying the optimality condition |
|
| 1056 |
for (int a = 0; a != _res_arc_num; ++a) {
|
|
| 1057 |
if (_res_cap[a] > 0 && |
|
| 1058 |
_cost[a] + _pi[_source[a]] - _pi[_target[a]] < 0) {
|
|
| 1059 |
Value delta = _res_cap[a]; |
|
| 1060 |
_excess[_source[a]] -= delta; |
|
| 1061 |
_excess[_target[a]] += delta; |
|
| 1062 |
_res_cap[a] = 0; |
|
| 1063 |
_res_cap[_reverse[a]] += delta; |
|
| 1064 |
} |
|
| 1065 |
} |
|
| 1066 |
|
|
| 1067 |
// Find active nodes (i.e. nodes with positive excess) |
|
| 1068 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 1069 |
if (_excess[u] > 0) _active_nodes.push_back(u); |
|
| 1070 |
} |
|
| 1071 |
|
|
| 1072 |
// Initialize the next arcs |
|
| 1073 |
for (int u = 0; u != _res_node_num; ++u) {
|
|
| 1074 |
_next_out[u] = _first_out[u]; |
|
| 1075 |
} |
|
| 1180 |
|
|
| 1181 |
// Initialize current phase |
|
| 1182 |
initPhase(); |
|
| 1076 | 1183 |
|
| 1077 | 1184 |
// Perform push and relabel operations |
| 1078 | 1185 |
while (_active_nodes.size() > 0) {
|
| 1079 |
LargeCost min_red_cost, rc; |
|
| 1186 |
LargeCost min_red_cost, rc, pi_n; |
|
| 1080 | 1187 |
Value delta; |
| 1081 | 1188 |
int n, t, a, last_out = _res_arc_num; |
| 1082 | 1189 |
|
| 1190 |
next_node: |
|
| 1083 | 1191 |
// Select an active node (FIFO selection) |
| 1084 |
next_node: |
|
| 1085 | 1192 |
n = _active_nodes.front(); |
| 1086 |
last_out = _sum_supply < 0 ? |
|
| 1087 |
_first_out[n+1] : _first_out[n+1] - 1; |
|
| 1088 |
|
|
| 1193 |
last_out = _first_out[n+1]; |
|
| 1194 |
pi_n = _pi[n]; |
|
| 1195 |
|
|
| 1089 | 1196 |
// Perform push operations if there are admissible arcs |
| 1090 | 1197 |
if (_excess[n] > 0) {
|
| 1091 | 1198 |
for (a = _next_out[n]; a != last_out; ++a) {
|
| 1092 | 1199 |
if (_res_cap[a] > 0 && |
| 1093 |
_cost[a] + |
|
| 1200 |
_cost[a] + pi_n - _pi[_target[a]] < 0) {
|
|
| 1094 | 1201 |
delta = std::min(_res_cap[a], _excess[n]); |
| 1095 | 1202 |
t = _target[a]; |
| 1096 | 1203 |
|
| 1097 | 1204 |
// Push-look-ahead heuristic |
| 1098 | 1205 |
Value ahead = -_excess[t]; |
| 1099 |
int last_out_t = _sum_supply < 0 ? |
|
| 1100 |
_first_out[t+1] : _first_out[t+1] - 1; |
|
| 1206 |
int last_out_t = _first_out[t+1]; |
|
| 1207 |
LargeCost pi_t = _pi[t]; |
|
| 1101 | 1208 |
for (int ta = _next_out[t]; ta != last_out_t; ++ta) {
|
| 1102 | 1209 |
if (_res_cap[ta] > 0 && |
| 1103 |
_cost[ta] + |
|
| 1210 |
_cost[ta] + pi_t - _pi[_target[ta]] < 0) |
|
| 1104 | 1211 |
ahead += _res_cap[ta]; |
| 1105 | 1212 |
if (ahead >= delta) break; |
| 1106 | 1213 |
} |
| 1107 | 1214 |
if (ahead < 0) ahead = 0; |
| 1108 | 1215 |
|
| 1109 | 1216 |
// Push flow along the arc |
| 1110 |
if (ahead < delta) {
|
|
| 1217 |
if (ahead < delta && !hyper[t]) {
|
|
| 1111 | 1218 |
_res_cap[a] -= ahead; |
| 1112 | 1219 |
_res_cap[_reverse[a]] += ahead; |
| 1113 | 1220 |
_excess[n] -= ahead; |
| 1114 | 1221 |
_excess[t] += ahead; |
| 1115 | 1222 |
_active_nodes.push_front(t); |
| 1116 | 1223 |
hyper[t] = true; |
| 1224 |
hyper_cost[t] = _cost[a] + pi_n - pi_t; |
|
| 1117 | 1225 |
_next_out[n] = a; |
| 1118 | 1226 |
goto next_node; |
| 1119 | 1227 |
} else {
|
| 1120 | 1228 |
_res_cap[a] -= delta; |
| 1121 | 1229 |
_res_cap[_reverse[a]] += delta; |
| 1122 | 1230 |
_excess[n] -= delta; |
| ... | ... |
@@ -1133,33 +1241,41 @@ |
| 1133 | 1241 |
} |
| 1134 | 1242 |
_next_out[n] = a; |
| 1135 | 1243 |
} |
| 1136 | 1244 |
|
| 1137 | 1245 |
// Relabel the node if it is still active (or hyper) |
| 1138 | 1246 |
if (_excess[n] > 0 || hyper[n]) {
|
| 1139 |
min_red_cost = |
|
| 1247 |
min_red_cost = hyper[n] ? -hyper_cost[n] : |
|
| 1248 |
std::numeric_limits<LargeCost>::max(); |
|
| 1140 | 1249 |
for (int a = _first_out[n]; a != last_out; ++a) {
|
| 1141 |
rc = _cost[a] + |
|
| 1250 |
rc = _cost[a] + pi_n - _pi[_target[a]]; |
|
| 1142 | 1251 |
if (_res_cap[a] > 0 && rc < min_red_cost) {
|
| 1143 | 1252 |
min_red_cost = rc; |
| 1144 | 1253 |
} |
| 1145 | 1254 |
} |
| 1146 | 1255 |
_pi[n] -= min_red_cost + _epsilon; |
| 1256 |
_next_out[n] = _first_out[n]; |
|
| 1147 | 1257 |
hyper[n] = false; |
| 1148 |
|
|
| 1149 |
// Reset the next arc |
|
| 1150 |
|
|
| 1258 |
++relabel_cnt; |
|
| 1151 | 1259 |
} |
| 1152 | 1260 |
|
| 1153 | 1261 |
// Remove nodes that are not active nor hyper |
| 1154 | 1262 |
remove_nodes: |
| 1155 | 1263 |
while ( _active_nodes.size() > 0 && |
| 1156 | 1264 |
_excess[_active_nodes.front()] <= 0 && |
| 1157 | 1265 |
!hyper[_active_nodes.front()] ) {
|
| 1158 | 1266 |
_active_nodes.pop_front(); |
| 1159 | 1267 |
} |
| 1268 |
|
|
| 1269 |
// Global update heuristic |
|
| 1270 |
if (relabel_cnt >= next_update_limit) {
|
|
| 1271 |
globalUpdate(); |
|
| 1272 |
for (int u = 0; u != _res_node_num; ++u) |
|
| 1273 |
hyper[u] = false; |
|
| 1274 |
next_update_limit += global_update_freq; |
|
| 1275 |
} |
|
| 1160 | 1276 |
} |
| 1161 | 1277 |
} |
| 1162 | 1278 |
} |
| 1163 | 1279 |
|
| 1164 | 1280 |
}; //class CostScaling |
| 1165 | 1281 |
| ... | ... |
@@ -141,16 +141,17 @@ |
| 141 | 141 |
|
| 142 | 142 |
private: |
| 143 | 143 |
|
| 144 | 144 |
TEMPLATE_DIGRAPH_TYPEDEFS(GR); |
| 145 | 145 |
|
| 146 | 146 |
typedef std::vector<int> IntVector; |
| 147 |
typedef std::vector<char> CharVector; |
|
| 148 | 147 |
typedef std::vector<double> DoubleVector; |
| 149 | 148 |
typedef std::vector<Value> ValueVector; |
| 150 | 149 |
typedef std::vector<Cost> CostVector; |
| 150 |
typedef std::vector<char> BoolVector; |
|
| 151 |
// Note: vector<char> is used instead of vector<bool> for efficiency reasons |
|
| 151 | 152 |
|
| 152 | 153 |
private: |
| 153 | 154 |
|
| 154 | 155 |
template <typename KT, typename VT> |
| 155 | 156 |
class StaticVectorMap {
|
| 156 | 157 |
public: |
| ... | ... |
@@ -195,13 +196,13 @@ |
| 195 | 196 |
|
| 196 | 197 |
// Data structures for storing the digraph |
| 197 | 198 |
IntNodeMap _node_id; |
| 198 | 199 |
IntArcMap _arc_idf; |
| 199 | 200 |
IntArcMap _arc_idb; |
| 200 | 201 |
IntVector _first_out; |
| 201 |
|
|
| 202 |
BoolVector _forward; |
|
| 202 | 203 |
IntVector _source; |
| 203 | 204 |
IntVector _target; |
| 204 | 205 |
IntVector _reverse; |
| 205 | 206 |
|
| 206 | 207 |
// Node and arc data |
| 207 | 208 |
ValueVector _lower; |
| ... | ... |
@@ -930,14 +931,14 @@ |
| 930 | 931 |
const double LIMIT_FACTOR = 1.0; |
| 931 | 932 |
const int MIN_LIMIT = 5; |
| 932 | 933 |
|
| 933 | 934 |
// Contruct auxiliary data vectors |
| 934 | 935 |
DoubleVector pi(_res_node_num, 0.0); |
| 935 | 936 |
IntVector level(_res_node_num); |
| 936 |
CharVector reached(_res_node_num); |
|
| 937 |
CharVector processed(_res_node_num); |
|
| 937 |
BoolVector reached(_res_node_num); |
|
| 938 |
BoolVector processed(_res_node_num); |
|
| 938 | 939 |
IntVector pred_node(_res_node_num); |
| 939 | 940 |
IntVector pred_arc(_res_node_num); |
| 940 | 941 |
std::vector<int> stack(_res_node_num); |
| 941 | 942 |
std::vector<int> proc_vector(_res_node_num); |
| 942 | 943 |
|
| 943 | 944 |
// Initialize epsilon |
| ... | ... |
@@ -161,15 +161,16 @@ |
| 161 | 161 |
|
| 162 | 162 |
private: |
| 163 | 163 |
|
| 164 | 164 |
TEMPLATE_DIGRAPH_TYPEDEFS(GR); |
| 165 | 165 |
|
| 166 | 166 |
typedef std::vector<int> IntVector; |
| 167 |
typedef std::vector<char> CharVector; |
|
| 168 | 167 |
typedef std::vector<Value> ValueVector; |
| 169 | 168 |
typedef std::vector<Cost> CostVector; |
| 169 |
typedef std::vector<char> BoolVector; |
|
| 170 |
// Note: vector<char> is used instead of vector<bool> for efficiency reasons |
|
| 170 | 171 |
|
| 171 | 172 |
// State constants for arcs |
| 172 | 173 |
enum ArcStateEnum {
|
| 173 | 174 |
STATE_UPPER = -1, |
| 174 | 175 |
STATE_TREE = 0, |
| 175 | 176 |
STATE_LOWER = 1 |
| ... | ... |
@@ -209,14 +210,14 @@ |
| 209 | 210 |
IntVector _pred; |
| 210 | 211 |
IntVector _thread; |
| 211 | 212 |
IntVector _rev_thread; |
| 212 | 213 |
IntVector _succ_num; |
| 213 | 214 |
IntVector _last_succ; |
| 214 | 215 |
IntVector _dirty_revs; |
| 215 |
CharVector _forward; |
|
| 216 |
CharVector _state; |
|
| 216 |
BoolVector _forward; |
|
| 217 |
BoolVector _state; |
|
| 217 | 218 |
int _root; |
| 218 | 219 |
|
| 219 | 220 |
// Temporary data used in the current pivot iteration |
| 220 | 221 |
int in_arc, join, u_in, v_in, u_out, v_out; |
| 221 | 222 |
int first, second, right, last; |
| 222 | 223 |
int stem, par_stem, new_stem; |
| ... | ... |
@@ -241,13 +242,13 @@ |
| 241 | 242 |
private: |
| 242 | 243 |
|
| 243 | 244 |
// References to the NetworkSimplex class |
| 244 | 245 |
const IntVector &_source; |
| 245 | 246 |
const IntVector &_target; |
| 246 | 247 |
const CostVector &_cost; |
| 247 |
const |
|
| 248 |
const BoolVector &_state; |
|
| 248 | 249 |
const CostVector &_pi; |
| 249 | 250 |
int &_in_arc; |
| 250 | 251 |
int _search_arc_num; |
| 251 | 252 |
|
| 252 | 253 |
// Pivot rule data |
| 253 | 254 |
int _next_arc; |
| ... | ... |
@@ -262,21 +263,21 @@ |
| 262 | 263 |
_next_arc(0) |
| 263 | 264 |
{}
|
| 264 | 265 |
|
| 265 | 266 |
// Find next entering arc |
| 266 | 267 |
bool findEnteringArc() {
|
| 267 | 268 |
Cost c; |
| 268 |
for (int e = _next_arc; e |
|
| 269 |
for (int e = _next_arc; e != _search_arc_num; ++e) {
|
|
| 269 | 270 |
c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 270 | 271 |
if (c < 0) {
|
| 271 | 272 |
_in_arc = e; |
| 272 | 273 |
_next_arc = e + 1; |
| 273 | 274 |
return true; |
| 274 | 275 |
} |
| 275 | 276 |
} |
| 276 |
for (int e = 0; e |
|
| 277 |
for (int e = 0; e != _next_arc; ++e) {
|
|
| 277 | 278 |
c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 278 | 279 |
if (c < 0) {
|
| 279 | 280 |
_in_arc = e; |
| 280 | 281 |
_next_arc = e + 1; |
| 281 | 282 |
return true; |
| 282 | 283 |
} |
| ... | ... |
@@ -293,13 +294,13 @@ |
| 293 | 294 |
private: |
| 294 | 295 |
|
| 295 | 296 |
// References to the NetworkSimplex class |
| 296 | 297 |
const IntVector &_source; |
| 297 | 298 |
const IntVector &_target; |
| 298 | 299 |
const CostVector &_cost; |
| 299 |
const |
|
| 300 |
const BoolVector &_state; |
|
| 300 | 301 |
const CostVector &_pi; |
| 301 | 302 |
int &_in_arc; |
| 302 | 303 |
int _search_arc_num; |
| 303 | 304 |
|
| 304 | 305 |
public: |
| 305 | 306 |
|
| ... | ... |
@@ -310,13 +311,13 @@ |
| 310 | 311 |
_in_arc(ns.in_arc), _search_arc_num(ns._search_arc_num) |
| 311 | 312 |
{}
|
| 312 | 313 |
|
| 313 | 314 |
// Find next entering arc |
| 314 | 315 |
bool findEnteringArc() {
|
| 315 | 316 |
Cost c, min = 0; |
| 316 |
for (int e = 0; e |
|
| 317 |
for (int e = 0; e != _search_arc_num; ++e) {
|
|
| 317 | 318 |
c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 318 | 319 |
if (c < min) {
|
| 319 | 320 |
min = c; |
| 320 | 321 |
_in_arc = e; |
| 321 | 322 |
} |
| 322 | 323 |
} |
| ... | ... |
@@ -332,13 +333,13 @@ |
| 332 | 333 |
private: |
| 333 | 334 |
|
| 334 | 335 |
// References to the NetworkSimplex class |
| 335 | 336 |
const IntVector &_source; |
| 336 | 337 |
const IntVector &_target; |
| 337 | 338 |
const CostVector &_cost; |
| 338 |
const |
|
| 339 |
const BoolVector &_state; |
|
| 339 | 340 |
const CostVector &_pi; |
| 340 | 341 |
int &_in_arc; |
| 341 | 342 |
int _search_arc_num; |
| 342 | 343 |
|
| 343 | 344 |
// Pivot rule data |
| 344 | 345 |
int _block_size; |
| ... | ... |
@@ -351,37 +352,37 @@ |
| 351 | 352 |
_source(ns._source), _target(ns._target), |
| 352 | 353 |
_cost(ns._cost), _state(ns._state), _pi(ns._pi), |
| 353 | 354 |
_in_arc(ns.in_arc), _search_arc_num(ns._search_arc_num), |
| 354 | 355 |
_next_arc(0) |
| 355 | 356 |
{
|
| 356 | 357 |
// The main parameters of the pivot rule |
| 357 |
const double BLOCK_SIZE_FACTOR = |
|
| 358 |
const double BLOCK_SIZE_FACTOR = 1.0; |
|
| 358 | 359 |
const int MIN_BLOCK_SIZE = 10; |
| 359 | 360 |
|
| 360 | 361 |
_block_size = std::max( int(BLOCK_SIZE_FACTOR * |
| 361 | 362 |
std::sqrt(double(_search_arc_num))), |
| 362 | 363 |
MIN_BLOCK_SIZE ); |
| 363 | 364 |
} |
| 364 | 365 |
|
| 365 | 366 |
// Find next entering arc |
| 366 | 367 |
bool findEnteringArc() {
|
| 367 | 368 |
Cost c, min = 0; |
| 368 | 369 |
int cnt = _block_size; |
| 369 | 370 |
int e; |
| 370 |
for (e = _next_arc; e |
|
| 371 |
for (e = _next_arc; e != _search_arc_num; ++e) {
|
|
| 371 | 372 |
c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 372 | 373 |
if (c < min) {
|
| 373 | 374 |
min = c; |
| 374 | 375 |
_in_arc = e; |
| 375 | 376 |
} |
| 376 | 377 |
if (--cnt == 0) {
|
| 377 | 378 |
if (min < 0) goto search_end; |
| 378 | 379 |
cnt = _block_size; |
| 379 | 380 |
} |
| 380 | 381 |
} |
| 381 |
for (e = 0; e |
|
| 382 |
for (e = 0; e != _next_arc; ++e) {
|
|
| 382 | 383 |
c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 383 | 384 |
if (c < min) {
|
| 384 | 385 |
min = c; |
| 385 | 386 |
_in_arc = e; |
| 386 | 387 |
} |
| 387 | 388 |
if (--cnt == 0) {
|
| ... | ... |
@@ -405,13 +406,13 @@ |
| 405 | 406 |
private: |
| 406 | 407 |
|
| 407 | 408 |
// References to the NetworkSimplex class |
| 408 | 409 |
const IntVector &_source; |
| 409 | 410 |
const IntVector &_target; |
| 410 | 411 |
const CostVector &_cost; |
| 411 |
const |
|
| 412 |
const BoolVector &_state; |
|
| 412 | 413 |
const CostVector &_pi; |
| 413 | 414 |
int &_in_arc; |
| 414 | 415 |
int _search_arc_num; |
| 415 | 416 |
|
| 416 | 417 |
// Pivot rule data |
| 417 | 418 |
IntVector _candidates; |
| ... | ... |
@@ -466,24 +467,24 @@ |
| 466 | 467 |
if (min < 0) return true; |
| 467 | 468 |
} |
| 468 | 469 |
|
| 469 | 470 |
// Major iteration: build a new candidate list |
| 470 | 471 |
min = 0; |
| 471 | 472 |
_curr_length = 0; |
| 472 |
for (e = _next_arc; e |
|
| 473 |
for (e = _next_arc; e != _search_arc_num; ++e) {
|
|
| 473 | 474 |
c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 474 | 475 |
if (c < 0) {
|
| 475 | 476 |
_candidates[_curr_length++] = e; |
| 476 | 477 |
if (c < min) {
|
| 477 | 478 |
min = c; |
| 478 | 479 |
_in_arc = e; |
| 479 | 480 |
} |
| 480 | 481 |
if (_curr_length == _list_length) goto search_end; |
| 481 | 482 |
} |
| 482 | 483 |
} |
| 483 |
for (e = 0; e |
|
| 484 |
for (e = 0; e != _next_arc; ++e) {
|
|
| 484 | 485 |
c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 485 | 486 |
if (c < 0) {
|
| 486 | 487 |
_candidates[_curr_length++] = e; |
| 487 | 488 |
if (c < min) {
|
| 488 | 489 |
min = c; |
| 489 | 490 |
_in_arc = e; |
| ... | ... |
@@ -508,13 +509,13 @@ |
| 508 | 509 |
private: |
| 509 | 510 |
|
| 510 | 511 |
// References to the NetworkSimplex class |
| 511 | 512 |
const IntVector &_source; |
| 512 | 513 |
const IntVector &_target; |
| 513 | 514 |
const CostVector &_cost; |
| 514 |
const |
|
| 515 |
const BoolVector &_state; |
|
| 515 | 516 |
const CostVector &_pi; |
| 516 | 517 |
int &_in_arc; |
| 517 | 518 |
int _search_arc_num; |
| 518 | 519 |
|
| 519 | 520 |
// Pivot rule data |
| 520 | 521 |
int _block_size, _head_length, _curr_length; |
| ... | ... |
@@ -561,38 +562,38 @@ |
| 561 | 562 |
} |
| 562 | 563 |
|
| 563 | 564 |
// Find next entering arc |
| 564 | 565 |
bool findEnteringArc() {
|
| 565 | 566 |
// Check the current candidate list |
| 566 | 567 |
int e; |
| 567 |
for (int i = 0; i |
|
| 568 |
for (int i = 0; i != _curr_length; ++i) {
|
|
| 568 | 569 |
e = _candidates[i]; |
| 569 | 570 |
_cand_cost[e] = _state[e] * |
| 570 | 571 |
(_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 571 | 572 |
if (_cand_cost[e] >= 0) {
|
| 572 | 573 |
_candidates[i--] = _candidates[--_curr_length]; |
| 573 | 574 |
} |
| 574 | 575 |
} |
| 575 | 576 |
|
| 576 | 577 |
// Extend the list |
| 577 | 578 |
int cnt = _block_size; |
| 578 | 579 |
int limit = _head_length; |
| 579 | 580 |
|
| 580 |
for (e = _next_arc; e |
|
| 581 |
for (e = _next_arc; e != _search_arc_num; ++e) {
|
|
| 581 | 582 |
_cand_cost[e] = _state[e] * |
| 582 | 583 |
(_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 583 | 584 |
if (_cand_cost[e] < 0) {
|
| 584 | 585 |
_candidates[_curr_length++] = e; |
| 585 | 586 |
} |
| 586 | 587 |
if (--cnt == 0) {
|
| 587 | 588 |
if (_curr_length > limit) goto search_end; |
| 588 | 589 |
limit = 0; |
| 589 | 590 |
cnt = _block_size; |
| 590 | 591 |
} |
| 591 | 592 |
} |
| 592 |
for (e = 0; e |
|
| 593 |
for (e = 0; e != _next_arc; ++e) {
|
|
| 593 | 594 |
_cand_cost[e] = _state[e] * |
| 594 | 595 |
(_cost[e] + _pi[_source[e]] - _pi[_target[e]]); |
| 595 | 596 |
if (_cand_cost[e] < 0) {
|
| 596 | 597 |
_candidates[_curr_length++] = e; |
| 597 | 598 |
} |
| 598 | 599 |
if (--cnt == 0) {
|
| ... | ... |
@@ -1325,13 +1326,13 @@ |
| 1325 | 1326 |
if (old_rev_thread != v_in) {
|
| 1326 | 1327 |
_thread[old_rev_thread] = right; |
| 1327 | 1328 |
_rev_thread[right] = old_rev_thread; |
| 1328 | 1329 |
} |
| 1329 | 1330 |
|
| 1330 | 1331 |
// Update _rev_thread using the new _thread values |
| 1331 |
for (int i = 0; i |
|
| 1332 |
for (int i = 0; i != int(_dirty_revs.size()); ++i) {
|
|
| 1332 | 1333 |
u = _dirty_revs[i]; |
| 1333 | 1334 |
_rev_thread[_thread[u]] = u; |
| 1334 | 1335 |
} |
| 1335 | 1336 |
|
| 1336 | 1337 |
// Update _pred, _forward, _last_succ and _succ_num for the |
| 1337 | 1338 |
// stem nodes from u_out to u_in |
| ... | ... |
@@ -1397,12 +1398,106 @@ |
| 1397 | 1398 |
int end = _thread[_last_succ[u_in]]; |
| 1398 | 1399 |
for (int u = u_in; u != end; u = _thread[u]) {
|
| 1399 | 1400 |
_pi[u] += sigma; |
| 1400 | 1401 |
} |
| 1401 | 1402 |
} |
| 1402 | 1403 |
|
| 1404 |
// Heuristic initial pivots |
|
| 1405 |
bool initialPivots() {
|
|
| 1406 |
Value curr, total = 0; |
|
| 1407 |
std::vector<Node> supply_nodes, demand_nodes; |
|
| 1408 |
for (NodeIt u(_graph); u != INVALID; ++u) {
|
|
| 1409 |
curr = _supply[_node_id[u]]; |
|
| 1410 |
if (curr > 0) {
|
|
| 1411 |
total += curr; |
|
| 1412 |
supply_nodes.push_back(u); |
|
| 1413 |
} |
|
| 1414 |
else if (curr < 0) {
|
|
| 1415 |
demand_nodes.push_back(u); |
|
| 1416 |
} |
|
| 1417 |
} |
|
| 1418 |
if (_sum_supply > 0) total -= _sum_supply; |
|
| 1419 |
if (total <= 0) return true; |
|
| 1420 |
|
|
| 1421 |
IntVector arc_vector; |
|
| 1422 |
if (_sum_supply >= 0) {
|
|
| 1423 |
if (supply_nodes.size() == 1 && demand_nodes.size() == 1) {
|
|
| 1424 |
// Perform a reverse graph search from the sink to the source |
|
| 1425 |
typename GR::template NodeMap<bool> reached(_graph, false); |
|
| 1426 |
Node s = supply_nodes[0], t = demand_nodes[0]; |
|
| 1427 |
std::vector<Node> stack; |
|
| 1428 |
reached[t] = true; |
|
| 1429 |
stack.push_back(t); |
|
| 1430 |
while (!stack.empty()) {
|
|
| 1431 |
Node u, v = stack.back(); |
|
| 1432 |
stack.pop_back(); |
|
| 1433 |
if (v == s) break; |
|
| 1434 |
for (InArcIt a(_graph, v); a != INVALID; ++a) {
|
|
| 1435 |
if (reached[u = _graph.source(a)]) continue; |
|
| 1436 |
int j = _arc_id[a]; |
|
| 1437 |
if (_cap[j] >= total) {
|
|
| 1438 |
arc_vector.push_back(j); |
|
| 1439 |
reached[u] = true; |
|
| 1440 |
stack.push_back(u); |
|
| 1441 |
} |
|
| 1442 |
} |
|
| 1443 |
} |
|
| 1444 |
} else {
|
|
| 1445 |
// Find the min. cost incomming arc for each demand node |
|
| 1446 |
for (int i = 0; i != int(demand_nodes.size()); ++i) {
|
|
| 1447 |
Node v = demand_nodes[i]; |
|
| 1448 |
Cost c, min_cost = std::numeric_limits<Cost>::max(); |
|
| 1449 |
Arc min_arc = INVALID; |
|
| 1450 |
for (InArcIt a(_graph, v); a != INVALID; ++a) {
|
|
| 1451 |
c = _cost[_arc_id[a]]; |
|
| 1452 |
if (c < min_cost) {
|
|
| 1453 |
min_cost = c; |
|
| 1454 |
min_arc = a; |
|
| 1455 |
} |
|
| 1456 |
} |
|
| 1457 |
if (min_arc != INVALID) {
|
|
| 1458 |
arc_vector.push_back(_arc_id[min_arc]); |
|
| 1459 |
} |
|
| 1460 |
} |
|
| 1461 |
} |
|
| 1462 |
} else {
|
|
| 1463 |
// Find the min. cost outgoing arc for each supply node |
|
| 1464 |
for (int i = 0; i != int(supply_nodes.size()); ++i) {
|
|
| 1465 |
Node u = supply_nodes[i]; |
|
| 1466 |
Cost c, min_cost = std::numeric_limits<Cost>::max(); |
|
| 1467 |
Arc min_arc = INVALID; |
|
| 1468 |
for (OutArcIt a(_graph, u); a != INVALID; ++a) {
|
|
| 1469 |
c = _cost[_arc_id[a]]; |
|
| 1470 |
if (c < min_cost) {
|
|
| 1471 |
min_cost = c; |
|
| 1472 |
min_arc = a; |
|
| 1473 |
} |
|
| 1474 |
} |
|
| 1475 |
if (min_arc != INVALID) {
|
|
| 1476 |
arc_vector.push_back(_arc_id[min_arc]); |
|
| 1477 |
} |
|
| 1478 |
} |
|
| 1479 |
} |
|
| 1480 |
|
|
| 1481 |
// Perform heuristic initial pivots |
|
| 1482 |
for (int i = 0; i != int(arc_vector.size()); ++i) {
|
|
| 1483 |
in_arc = arc_vector[i]; |
|
| 1484 |
if (_state[in_arc] * (_cost[in_arc] + _pi[_source[in_arc]] - |
|
| 1485 |
_pi[_target[in_arc]]) >= 0) continue; |
|
| 1486 |
findJoinNode(); |
|
| 1487 |
bool change = findLeavingArc(); |
|
| 1488 |
if (delta >= MAX) return false; |
|
| 1489 |
changeFlow(change); |
|
| 1490 |
if (change) {
|
|
| 1491 |
updateTreeStructure(); |
|
| 1492 |
updatePotential(); |
|
| 1493 |
} |
|
| 1494 |
} |
|
| 1495 |
return true; |
|
| 1496 |
} |
|
| 1497 |
|
|
| 1403 | 1498 |
// Execute the algorithm |
| 1404 | 1499 |
ProblemType start(PivotRule pivot_rule) {
|
| 1405 | 1500 |
// Select the pivot rule implementation |
| 1406 | 1501 |
switch (pivot_rule) {
|
| 1407 | 1502 |
case FIRST_ELIGIBLE: |
| 1408 | 1503 |
return start<FirstEligiblePivotRule>(); |
| ... | ... |
@@ -1419,12 +1514,15 @@ |
| 1419 | 1514 |
} |
| 1420 | 1515 |
|
| 1421 | 1516 |
template <typename PivotRuleImpl> |
| 1422 | 1517 |
ProblemType start() {
|
| 1423 | 1518 |
PivotRuleImpl pivot(*this); |
| 1424 | 1519 |
|
| 1520 |
// Perform heuristic initial pivots |
|
| 1521 |
if (!initialPivots()) return UNBOUNDED; |
|
| 1522 |
|
|
| 1425 | 1523 |
// Execute the Network Simplex algorithm |
| 1426 | 1524 |
while (pivot.findEnteringArc()) {
|
| 1427 | 1525 |
findJoinNode(); |
| 1428 | 1526 |
bool change = findLeavingArc(); |
| 1429 | 1527 |
if (delta >= MAX) return UNBOUNDED; |
| 1430 | 1528 |
changeFlow(change); |
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