Changes in lemon/network_simplex.h [840:2914b6f0fde0:830:75c97c3786d6] in lemon-main

File:

• lemon/network_simplex.h (modified) (21 diffs)

lemon/network_simplex.h

@@ -165 +165 @@
 
     typedef std::vector<int> IntVector;
+    typedef std::vector<char> CharVector;
     typedef std::vector<Value> ValueVector;
     typedef std::vector<Cost> CostVector;
-    typedef std::vector<char> BoolVector;
-    // Note: vector<char> is used instead of vector<bool> for efficiency reasons
 
     // State constants for arcs
@@ -215 +214 @@
     IntVector _last_succ;
     IntVector _dirty_revs;
-    BoolVector _forward;
-    BoolVector _state;
+    CharVector _forward;
+    CharVector _state;
     int _root;
 
@@ -247 +246 @@
       const IntVector  &_target;
       const CostVector &_cost;
-      const BoolVector &_state;
+      const CharVector &_state;
       const CostVector &_pi;
       int &_in_arc;
@@ -268 +267 @@
       bool findEnteringArc() {
         Cost c;
-        for (int e = _next_arc; e != _search_arc_num; ++e) {
+        for (int e = _next_arc; e < _search_arc_num; ++e) {
           c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
           if (c < 0) {
@@ -276 +275 @@
           }
         }
-        for (int e = 0; e != _next_arc; ++e) {
+        for (int e = 0; e < _next_arc; ++e) {
           c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
           if (c < 0) {
@@ -299 +298 @@
       const IntVector  &_target;
       const CostVector &_cost;
-      const BoolVector &_state;
+      const CharVector &_state;
       const CostVector &_pi;
       int &_in_arc;
@@ -316 +315 @@
       bool findEnteringArc() {
         Cost c, min = 0;
-        for (int e = 0; e != _search_arc_num; ++e) {
+        for (int e = 0; e < _search_arc_num; ++e) {
           c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
           if (c < min) {
@@ -338 +337 @@
       const IntVector  &_target;
       const CostVector &_cost;
-      const BoolVector &_state;
+      const CharVector &_state;
       const CostVector &_pi;
       int &_in_arc;
@@ -357 +356 @@
       {
         // The main parameters of the pivot rule
-        const double BLOCK_SIZE_FACTOR = 1.0;
+        const double BLOCK_SIZE_FACTOR = 0.5;
         const int MIN_BLOCK_SIZE = 10;
 
@@ -370 +369 @@
         int cnt = _block_size;
         int e;
-        for (e = _next_arc; e != _search_arc_num; ++e) {
+        for (e = _next_arc; e < _search_arc_num; ++e) {
           c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
           if (c < min) {
@@ -381 +380 @@
           }
         }
-        for (e = 0; e != _next_arc; ++e) {
+        for (e = 0; e < _next_arc; ++e) {
           c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
           if (c < min) {
@@ -411 +410 @@
       const IntVector  &_target;
       const CostVector &_cost;
-      const BoolVector &_state;
+      const CharVector &_state;
       const CostVector &_pi;
       int &_in_arc;
@@ -472 +471 @@
         min = 0;
         _curr_length = 0;
-        for (e = _next_arc; e != _search_arc_num; ++e) {
+        for (e = _next_arc; e < _search_arc_num; ++e) {
           c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
           if (c < 0) {
@@ -483 +482 @@
           }
         }
-        for (e = 0; e != _next_arc; ++e) {
+        for (e = 0; e < _next_arc; ++e) {
           c = _state[e] * (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
           if (c < 0) {
@@ -514 +513 @@
       const IntVector  &_target;
       const CostVector &_cost;
-      const BoolVector &_state;
+      const CharVector &_state;
       const CostVector &_pi;
       int &_in_arc;
@@ -567 +566 @@
         // Check the current candidate list
         int e;
-        for (int i = 0; i != _curr_length; ++i) {
+        for (int i = 0; i < _curr_length; ++i) {
           e = _candidates[i];
           _cand_cost[e] = _state[e] *
@@ -580 +579 @@
         int limit = _head_length;
 
-        for (e = _next_arc; e != _search_arc_num; ++e) {
+        for (e = _next_arc; e < _search_arc_num; ++e) {
           _cand_cost[e] = _state[e] *
             (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
@@ -592 +591 @@
           }
         }
-        for (e = 0; e != _next_arc; ++e) {
+        for (e = 0; e < _next_arc; ++e) {
           _cand_cost[e] = _state[e] *
             (_cost[e] + _pi[_source[e]] - _pi[_target[e]]);
@@ -1362 +1361 @@
 
       // Update _rev_thread using the new _thread values
-      for (int i = 0; i != int(_dirty_revs.size()); ++i) {
+      for (int i = 0; i < int(_dirty_revs.size()); ++i) {
         u = _dirty_revs[i];
         _rev_thread[_thread[u]] = u;
@@ -1432 +1431 @@
         _pi[u] += sigma;
       }
-    }
-
-    // Heuristic initial pivots
-    bool initialPivots() {
-      Value curr, total = 0;
-      std::vector<Node> supply_nodes, demand_nodes;
-      for (NodeIt u(_graph); u != INVALID; ++u) {
-        curr = _supply[_node_id[u]];
-        if (curr > 0) {
-          total += curr;
-          supply_nodes.push_back(u);
-        }
-        else if (curr < 0) {
-          demand_nodes.push_back(u);
-        }
-      }
-      if (_sum_supply > 0) total -= _sum_supply;
-      if (total <= 0) return true;
-
-      IntVector arc_vector;
-      if (_sum_supply >= 0) {
-        if (supply_nodes.size() == 1 && demand_nodes.size() == 1) {
-          // Perform a reverse graph search from the sink to the source
-          typename GR::template NodeMap<bool> reached(_graph, false);
-          Node s = supply_nodes[0], t = demand_nodes[0];
-          std::vector<Node> stack;
-          reached[t] = true;
-          stack.push_back(t);
-          while (!stack.empty()) {
-            Node u, v = stack.back();
-            stack.pop_back();
-            if (v == s) break;
-            for (InArcIt a(_graph, v); a != INVALID; ++a) {
-              if (reached[u = _graph.source(a)]) continue;
-              int j = _arc_id[a];
-              if (_cap[j] >= total) {
-                arc_vector.push_back(j);
-                reached[u] = true;
-                stack.push_back(u);
-              }
-            }
-          }
-        } else {
-          // Find the min. cost incomming arc for each demand node
-          for (int i = 0; i != int(demand_nodes.size()); ++i) {
-            Node v = demand_nodes[i];
-            Cost c, min_cost = std::numeric_limits<Cost>::max();
-            Arc min_arc = INVALID;
-            for (InArcIt a(_graph, v); a != INVALID; ++a) {
-              c = _cost[_arc_id[a]];
-              if (c < min_cost) {
-                min_cost = c;
-                min_arc = a;
-              }
-            }
-            if (min_arc != INVALID) {
-              arc_vector.push_back(_arc_id[min_arc]);
-            }
-          }
-        }
-      } else {
-        // Find the min. cost outgoing arc for each supply node
-        for (int i = 0; i != int(supply_nodes.size()); ++i) {
-          Node u = supply_nodes[i];
-          Cost c, min_cost = std::numeric_limits<Cost>::max();
-          Arc min_arc = INVALID;
-          for (OutArcIt a(_graph, u); a != INVALID; ++a) {
-            c = _cost[_arc_id[a]];
-            if (c < min_cost) {
-              min_cost = c;
-              min_arc = a;
-            }
-          }
-          if (min_arc != INVALID) {
-            arc_vector.push_back(_arc_id[min_arc]);
-          }
-        }
-      }
-
-      // Perform heuristic initial pivots
-      for (int i = 0; i != int(arc_vector.size()); ++i) {
-        in_arc = arc_vector[i];
-        if (_state[in_arc] * (_cost[in_arc] + _pi[_source[in_arc]] -
-            _pi[_target[in_arc]]) >= 0) continue;
-        findJoinNode();
-        bool change = findLeavingArc();
-        if (delta >= MAX) return false;
-        changeFlow(change);
-        if (change) {
-          updateTreeStructure();
-          updatePotential();
-        }
-      }
-      return true;
     }
 
@@ -1550 +1455 @@
       PivotRuleImpl pivot(*this);
 
-      // Perform heuristic initial pivots
-      if (!initialPivots()) return UNBOUNDED;
-
       // Execute the Network Simplex algorithm
       while (pivot.findEnteringArc()) {