diff --git a/README.md b/README.md
index d894bc1d9b395db0e7e8580b9d248ba349948973..a305b5fe4b400c77275ce0365fd75a9f9376a87d 100644
--- a/README.md
+++ b/README.md
@@ -18,11 +18,11 @@ If you use the code from this repository, please cite
publisher = {},
}
```
-For questions, please contact elina.ronnberg@liu.se
+For questions, please contact lukas.eveborn@liu.se
### Electric Vehicle Routing Problem with Time Windows and Piecewise Linear Charging Function
The instances that we use were introduced by M. Schneider, A. Stenger and D. Goeke *The Electric Vehicle-Routing Problem with Time Windows and Recharging Stations*, and can be found at https://data.mendeley.com/datasets/h3mrm5dhxw/1
-These instances are based on the benchmark indtances for the VRP of M.M. Solomon *Algorithms for the Vehicle Routing and Scheduling Problems with Time Window Constraints*.
+These instances are based on the benchmark instances for the VRP of M.M. Solomon *Algorithms for the Vehicle Routing and Scheduling Problems with Time Window Constraints*.
## Code
The code that was used in the paper is found in this repository.
diff --git a/src/evrp_data_subproblem.h b/src/evrp_data_subproblem.h
index 9ed16b564d5ca9b6d80c9c0f7e25ba7393b8632e..1614aa11bb3686aa8dfe3dfb356938b9fd8899b0 100644
--- a/src/evrp_data_subproblem.h
+++ b/src/evrp_data_subproblem.h
@@ -34,7 +34,9 @@ struct Node
double min_time_arc;
double min_fuel_arc;
- double min_time_incoming;
+ double min_time_incoming_ng;
+ double min_time_outgoing_ng;
+
};
struct Arc
diff --git a/src/labelling_algorithm.cpp b/src/labelling_algorithm.cpp
index 9e68e2ff1a428cc32cd30393311eb122b05fb2ad..8e5a38014f222385a2123a95686085ac5da097be 100644
--- a/src/labelling_algorithm.cpp
+++ b/src/labelling_algorithm.cpp
@@ -671,16 +671,6 @@ void LabellingAlgorithm::assign_min_arc()
least_arc_costs.push_back(make_tuple(nodes.uniqueNodeIndex, cost / nodeInfo[nodes.uniqueNodeIndex].demand));
least_arc_time.push_back(make_tuple(nodes.uniqueNodeIndex, cost / (time + (refuel / charging_rates[0]))));
- // Incoming arcs to compute multiplicity of visits in ng-completion
- time = 1000;
- for (auto incoming : nodes.incomingNodes)
- {
- if (nodeInfo[incoming].nodeType != 'f')
- {
- time = min(time, arcInfo[incoming][nodes.uniqueNodeIndex].time + nodeInfo[incoming].serviceTime);
- }
- }
- nodeInfo[nodes.uniqueNodeIndex].min_time_incoming = time;
}
sort(least_arc_costs.begin(), least_arc_costs.end(), compare_cost); // sort the queues cost/demand and cost/(time+refueltime) in increasing order (most negative value first)
sort(least_arc_time.begin(), least_arc_time.end(), compare_cost);
@@ -1049,6 +1039,28 @@ void LabellingAlgorithm::get_ng_sets(int size)
closest.push_back(node.uniqueNodeIndex); // insert node itself into ints ng-set
ng_set[node.uniqueNodeIndex] = closest;
}
+
+
+ //find the node k closest to node i, such that i is not in the ng-set of k
+ for(auto node: nodeInfo){
+ double closest_incoming=1000000;
+ double closest_outgoing=1000000;
+ for(auto next: nodeInfo){ //check all arcs
+ if(next.nodeType=='f'){
+ continue;
+ }
+ else{
+ int neighbour=next.uniqueNodeIndex;
+ if(find(ng_set[neighbour].begin(),ng_set[neighbour].end(),node.uniqueNodeIndex)==ng_set[neighbour].end()){
+ closest_incoming=min(closest_incoming,arcInfo[node.uniqueNodeIndex][neighbour].time+nodeInfo[neighbour].serviceTime);
+ closest_outgoing=min(closest_outgoing,arcInfo[node.uniqueNodeIndex][neighbour].time+nodeInfo[node.uniqueNodeIndex].serviceTime);
+ }
+ }
+ }
+ node.min_time_incoming_ng=closest_incoming;
+ node.min_time_outgoing_ng=closest_outgoing;
+ }
+
}
/**
@@ -1155,13 +1167,7 @@ double LabellingAlgorithm::get_capacity_bound(Label* label, bool ng)
double cost=nodeInfo[labelNode].min_cost_arc;
double resource_left=maxResource.capacity-label->capacity;
-
double earliest_start_time=label->tMin+nodeInfo[labelNode].serviceTime;
-
- vector<tuple<int,int,int>> visited_in_completion; //node identifier, multiple of visits, maximum visits
- visited_in_completion.reserve(20);
-
-
int i=0;
while(i<least_arc_costs.size()){
int currNode=get<0>(least_arc_costs[i]);
@@ -1170,67 +1176,21 @@ double LabellingAlgorithm::get_capacity_bound(Label* label, bool ng)
continue;
}
if(label->visitedForDominance[currNode]==0 || ng){ //node has not been visited before
- if(ng){
- //add nodes to completion calculate the number of times it can be visited
- int completion_size=visited_in_completion.size();
- if(completion_size<2){ //special case when adding the first two nodes
- if(earliest_start_time+arcInfo[labelNode][currNode].time>nodeInfo[currNode].dueDate){
- i++; //find first customer node that is reachable
- continue;
- }
- if(completion_size==0 && label->visitedForDominance[currNode]==1){ //if first node in completion, and label remembers first node
- int k=i+1; //find best node that is not remembered and can be reached
- while(k<least_arc_costs.size()){
- if(label->visitedForDominance[get<0>(least_arc_costs[k])]==0 && earliest_start_time+arcInfo[labelNode][get<0>(least_arc_costs[k])].time<=nodeInfo[get<0>(least_arc_costs[k])].dueDate){
- currNode=get<0>(least_arc_costs[k]); //k is reachable, not remebered by the label, and not a charging node
- i=i-1; //the recent i was not added in the completion, but is valid
- break;
- }
- else{
- k++;
- }
- }
- }
-
- double start_time=max(earliest_start_time+arcInfo[labelNode][currNode].time,nodeInfo[currNode].readyTime);
- int multiplicity=ceil((nodeInfo[currNode].dueDate-start_time)/(nodeInfo[currNode].min_time_arc+nodeInfo[currNode].min_time_incoming));
- visited_in_completion.emplace_back(make_tuple(currNode,1,multiplicity));
- i++;
-
- }
- else{
- tuple<int,int,int> node=visited_in_completion[completion_size-2];
- if(get<1>(node)<get<2>(node)){ //check if any node can still be revisited. Reachability must not be tested here
- visited_in_completion.emplace_back(make_tuple(get<0>(node), get<1>(node)+1,get<2>(node)));
- currNode=get<0>(node);
- }
- else if(earliest_start_time+arcInfo[labelNode][currNode].time>nodeInfo[currNode].dueDate){ //verify reachability of new node
- i++;
- continue;
- }
- else{
- double start_time=max(earliest_start_time+arcInfo[labelNode][currNode].time,nodeInfo[currNode].readyTime); //add new node
- int multiplicity=ceil((nodeInfo[currNode].dueDate-start_time)/(nodeInfo[currNode].min_time_arc+nodeInfo[currNode].min_time_incoming));
- visited_in_completion.emplace_back(make_tuple(currNode,1,multiplicity));
- i++;
- }
- }
- }
-
if(nodeInfo[currNode].min_cost_arc>=0){
- if(ng){
- if(visited_in_completion.size()!=1){ //the first added node may have positive cost
- break;
- }
- }
- else{
- break;
- }
+ break;
}
+ double multiplicity=1;
+ if(ng){ //must check if it can be reached!
+ double start_time=max(earliest_start_time+arcInfo[labelNode][currNode].time,nodeInfo[currNode].readyTime);
+ if(start_time>nodeInfo[currNode].dueDate){
+ i++;
+ continue;
+ }
+ multiplicity=floor((nodeInfo[currNode].dueDate-start_time)/(nodeInfo[currNode].min_time_outgoing_ng+nodeInfo[currNode].min_time_incoming_ng))+1;
+ }
float value;
- value=min((double)1,resource_left/nodeInfo[currNode].demand);
-
+ value=min((double)multiplicity,resource_left/nodeInfo[currNode].demand);
resource_left=resource_left-(nodeInfo[currNode].demand*value);
cost=cost+(nodeInfo[currNode].min_cost_arc*value);
@@ -1239,18 +1199,14 @@ double LabellingAlgorithm::get_capacity_bound(Label* label, bool ng)
}
}
- if(!ng){
- i++;
- }
- }
- if(ng){
- return(min(cost,nodeInfo[labelNode].min_cost_arc));
- }
- else{
- return(cost);
+ i++;
}
+
+ return(cost);
}
+
+
/**
* \fn time_bound_special
* \brief adapted knapsack time bounds with battery constraints
@@ -1269,13 +1225,11 @@ double LabellingAlgorithm::get_time_bound(Label* label, bool ng)
}
double resource_left=maxResource.tMin-label->tMin-nodeInfo[labelNode].min_time_arc-added_time; //reduce time availability
-
double earliest_start_time=label->tMin+nodeInfo[labelNode].serviceTime;
double added_charging;
double required_charging;
- vector<tuple <int,int,int>> visited_in_completion; //node identifier, multiplicity of visits, maximum visits
- visited_in_completion.reserve(15);
+
int i=0;
while(i<least_arc_time.size()){
@@ -1286,89 +1240,33 @@ double LabellingAlgorithm::get_time_bound(Label* label, bool ng)
continue;
}
else if(label->visitedForDominance[currNode]==0 || ng){
- if(ng){
- // add nodes to completion and calculate the number of times it can be visited
- int completion_size=visited_in_completion.size();
-
- if(completion_size<2){ //special case for first two nodes int the completion
- if(label->tMin+nodeInfo[labelNode].serviceTime+arcInfo[labelNode][currNode].time>nodeInfo[currNode].dueDate){
- i++; //find first customer node in list that is reachable
- continue;
- }
- if(completion_size==0 && label->visitedForDominance[currNode]==1){ //first node in completion may not be rememebered byt the label
- int k=i+1;
- while(k<least_arc_time.size()){
- if(label->visitedForDominance[get<0>(least_arc_time[k])]==0 && label->tMin+nodeInfo[labelNode].serviceTime+arcInfo[labelNode][get<0>(least_arc_time[k])].time<=nodeInfo[get<0>(least_arc_time[k])].dueDate && nodeInfo[get<0>(least_arc_time[k])].nodeType!='f'){
- currNode=get<0>(least_arc_time[k]);
- i=i-1; //i is valid, and has not been added to completion
- break;
- }
- else{
- k++;
- }
- }
- }
- double start_time=max(earliest_start_time+arcInfo[labelNode][currNode].time,nodeInfo[currNode].readyTime);
- int multiplicity=ceil((nodeInfo[currNode].dueDate-start_time)/(nodeInfo[currNode].min_time_arc+nodeInfo[currNode].min_time_incoming));
- visited_in_completion.emplace_back(make_tuple(currNode,1,multiplicity));
- i++;
- }
- else{
- tuple<int,int,int>node=visited_in_completion[completion_size-2];
-
- if(get<1>(node)<get<2>(node)){ //check second to last node can still be revisited. Reachability must not be tested
- visited_in_completion.emplace_back(make_tuple(get<0>(node), get<1>(node)+1,get<2>(node)));
- currNode=get<0>(node);
-
- }
- else if(label->tMin+nodeInfo[labelNode].serviceTime+arcInfo[labelNode][currNode].time>nodeInfo[currNode].dueDate){
- i++; //else find next node that is reachable
- continue;
- }
- else{ //add node to completion of the path
- double start_time=max(earliest_start_time+arcInfo[labelNode][currNode].time,nodeInfo[currNode].readyTime);
- int multiplicity=ceil((nodeInfo[currNode].dueDate-start_time)/(nodeInfo[currNode].min_time_arc+nodeInfo[currNode].min_time_incoming));
- visited_in_completion.emplace_back(make_tuple(currNode,1,multiplicity));
- i++;
- }
- }
- }
-
- if(nodeInfo[currNode].min_cost_arc>=0){
- if(ng){
- if(visited_in_completion.size()!=1){ //the first added node may have positive cost
- break;
- }
- }
- else{
- break;
+
+ if(nodeInfo[currNode].min_cost_arc>=0){
+ break;
+ }
+
+ double multiplicity=1;
+ if(ng){
+ double start_time=max(earliest_start_time+arcInfo[labelNode][currNode].time,nodeInfo[currNode].readyTime);
+ if(start_time>nodeInfo[currNode].dueDate){
+ i++;
+ continue;
}
+ multiplicity=floor((nodeInfo[currNode].dueDate-start_time)/(nodeInfo[currNode].min_time_outgoing_ng+nodeInfo[currNode].min_time_incoming_ng))+1;
}
-
float value;
-
added_charging=max((double)0,nodeInfo[currNode].min_fuel_arc-energy)/charging_rates[0]; //charging time at fastest rate
energy=max((double)0.0,energy-nodeInfo[currNode].min_fuel_arc); //update the energy resource
- value=min((double)1,resource_left/(nodeInfo[currNode].min_time_arc+added_charging));
+ value=min((double)multiplicity,resource_left/(nodeInfo[currNode].min_time_arc+added_charging));
resource_left=resource_left-(nodeInfo[currNode].min_time_arc+added_charging)*value;
-
cost=cost+(nodeInfo[currNode].min_cost_arc*value);
if(resource_left<=0){
break;
- }
-
+ }
}
- if(!ng){
- i++;
- }
- }
-
- if(ng){
- return(min(cost,nodeInfo[labelNode].min_cost_arc));
- }
- else{
- return(cost);
+ i++;
}
+ return(cost);
}