private static void Swap(NodeInfo[] nodes, int i, int j)
{
var temp = nodes[i];
nodes[i] = nodes[j];
nodes[j] = temp;
}
static void ReadVRP(string fName)
{
string[] lines = File.ReadAllLines(fName);
string[] header = lines[0].Split(' ');
numNodes = int.Parse(header[0]);
numTrucks = int.Parse(header[1]);
truckCapacity = int.Parse(header[2]);
string[] whStr = lines[1].Split(' ');
wareHouseLoc = new Point() {
x = double.Parse(whStr[1]),
y = double.Parse(whStr[2])
};
/*nodes[0] always refers to the warehouse location
the actual nodes begin from nodes[1]*/
nodes = new NodeInfo[numNodes];
demands = new int[numNodes];
nodes[0] = new NodeInfo() {
demand = 0,
point = wareHouseLoc,
id = 0
};
int currNode = 1;
for (int i = 2; i <= numNodes; i++) {
string[] nodeStr = lines[i].Split(' ');
Point p = new Point() {
x = double.Parse(nodeStr[1]),
y = double.Parse(nodeStr[2])
};
NodeInfo n = new NodeInfo() {
id = currNode,
demand = int.Parse(nodeStr[0]),
point = p
};
demands[currNode] = n.demand;
nodes[currNode] = n;
currNode++;
}
distMatrix = new double[numNodes, numNodes];
/*calculate the distance between every pair of nodes*/
for (int i = 0; i < numNodes; i++) {
for (int j = 0; j < numNodes; j++) {
if (i != j) {
distMatrix[i, j] = Dist(nodes[i].point, nodes[j].point);
}
}
}
}
private static void Shuffle(NodeInfo[] nodes)
{
Random rnd = new Random();
int numNodes = nodes.Length;
for (int i = 0; i < nodes.Length; i++)
Swap(nodes, i, rnd.Next(i, numNodes));
}
private static Solution GetInitialFeasibleSolution(NodeInfo[] nodes)
{
Solution soln = new Solution();
int currTruck = 1;
bool allDemandSatisfied = false;
HashSet<int> assignedNodes = new HashSet<int>();
while (!allDemandSatisfied && currTruck <= numTrucks) {
int availableCap = truckCapacity;
//iterate over each of the nodes and if any node has not been assigned yet
//to any truck and the capacity constraints of the truck are satisfied, then
//assign this node to this truck.
Route thisRoute = new Route();
thisRoute.ids.Add(0);
thisRoute.truckId = currTruck;
thisRoute.unusedDemand = availableCap;
for (int i = 0; i < nodes.Length; i++) {
if (nodes[i].id != 0) {
int thisNodeId = nodes[i].id;
int thisNodeDemand = demands[thisNodeId];
if (!assignedNodes.Contains(thisNodeId) && availableCap >= thisNodeDemand) {
availableCap -= thisNodeDemand;
assignedNodes.Add(thisNodeId);
thisRoute.ids.Add(thisNodeId);
thisRoute.unusedDemand = availableCap;
if (assignedNodes.Count == nodes.Length - 1) {
allDemandSatisfied = true;
break;
}
}
}
}
//thisRoute.ids.Add(0); /*to keep it consistent with tsp routines*/
CalculateRouteDistance(thisRoute);
soln.routes.Add(thisRoute);
currTruck++;
}
if (!allDemandSatisfied) {
return null;
} else {
//fill up additional trucks with path : 0-0
int usedTrucks = soln.routes.Count;
for (int i = 0; i < numTrucks - usedTrucks; i++) {
soln.routes.Add(new Route() {
ids = new List<int>() {0},
totalDist = 0,
unusedDemand = truckCapacity,
truckId = currTruck++
});
}
return soln;
}
}