public void PrintNetworkFlowSolution(MinCostFlow networkFlowSolution)
{
long optimalCost = networkFlowSolution.OptimalCost();
Console.WriteLine("Minimum cost: " + optimalCost);
Console.WriteLine("");
Console.WriteLine(" Edge Flow / Capacity Cost");
for (int i = 0; i < numArcs; ++i)
{
long cost = networkFlowSolution.Flow(i) * networkFlowSolution.UnitCost(i);
Console.WriteLine(networkFlowSolution.Tail(i) + " -> " +
networkFlowSolution.Head(i) + " " +
string.Format("{0,3}", networkFlowSolution.Flow(i)) + " / " +
string.Format("{0,3}", networkFlowSolution.Capacity(i)) + " " +
string.Format("{0,3}", cost));
}
}
static void Main()
{
// [START data]
// Define four parallel arrays: sources, destinations, capacities, and unit costs
// between each pair. For instance, the arc from node 0 to node 1 has a
// capacity of 15.
// Problem taken From Taha's 'Introduction to Operations Research',
// example 6.4-2.
int[] startNodes = { 0, 0, 1, 1, 1, 2, 2, 3, 4 };
int[] endNodes = { 1, 2, 2, 3, 4, 3, 4, 4, 2 };
int[] capacities = { 15, 8, 20, 4, 10, 15, 4, 20, 5 };
int[] unitCosts = { 4, 4, 2, 2, 6, 1, 3, 2, 3 };
// Define an array of supplies at each node.
int[] supplies = { 20, 0, 0, -5, -15 };
// [END data]
// [START constraints]
// Instantiate a SimpleMinCostFlow solver.
MinCostFlow minCostFlow = new MinCostFlow();
// Add each arc.
for (int i = 0; i < startNodes.Length; ++i)
{
int arc =
minCostFlow.AddArcWithCapacityAndUnitCost(startNodes[i], endNodes[i], capacities[i], unitCosts[i]);
if (arc != i)
{
throw new Exception("Internal error");
}
}
// Add node supplies.
for (int i = 0; i < supplies.Length; ++i)
{
minCostFlow.SetNodeSupply(i, supplies[i]);
}
// [END constraints]
// [START solve]
// Find the min cost flow.
MinCostFlow.Status solveStatus = minCostFlow.Solve();
// [END solve]
// [START print_solution]
if (solveStatus == MinCostFlow.Status.OPTIMAL)
{
Console.WriteLine("Minimum cost: " + minCostFlow.OptimalCost());
Console.WriteLine("");
Console.WriteLine(" Edge Flow / Capacity Cost");
for (int i = 0; i < minCostFlow.NumArcs(); ++i)
{
long cost = minCostFlow.Flow(i) * minCostFlow.UnitCost(i);
Console.WriteLine(minCostFlow.Tail(i) + " -> " + minCostFlow.Head(i) + " " +
string.Format("{0,3}", minCostFlow.Flow(i)) + " / " +
string.Format("{0,3}", minCostFlow.Capacity(i)) + " " +
string.Format("{0,3}", cost));
}
}
else
{
Console.WriteLine("Solving the min cost flow problem failed. Solver status: " + solveStatus);
}
// [END print_solution]
}
static void Main()
{
// [START solver]
// Instantiate a SimpleMinCostFlow solver.
MinCostFlow minCostFlow = new MinCostFlow();
// [END solver]
// [START data]
// Define the directed graph for the flow.
int[] teamA = { 1, 3, 5 };
int[] teamB = { 2, 4, 6 };
// Define four parallel arrays: sources, destinations, capacities, and unit costs
// between each pair.
int[] startNodes = { 0, 0, 11, 11, 11, 12, 12, 12, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3,
3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 8, 9, 10 };
int[] endNodes = { 11, 12, 1, 3, 5, 2, 4, 6, 7, 8, 9, 10, 7, 8, 9, 10, 7, 8,
9, 10, 7, 8, 9, 10, 7, 8, 9, 10, 7, 8, 9, 10, 13, 13, 13, 13 };
int[] capacities = { 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
int[] unitCosts = { 0, 0, 0, 0, 0, 0, 0, 0, 90, 76, 75, 70, 35, 85, 55, 65, 125, 95,
90, 105, 45, 110, 95, 115, 60, 105, 80, 75, 45, 65, 110, 95, 0, 0, 0, 0 };
int source = 0;
int sink = 13;
// Define an array of supplies at each node.
int[] supplies = { 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -4 };
// [END data]
// [START constraints]
// Add each arc.
for (int i = 0; i < startNodes.Length; ++i)
{
int arc =
minCostFlow.AddArcWithCapacityAndUnitCost(startNodes[i], endNodes[i], capacities[i], unitCosts[i]);
if (arc != i)
{
throw new Exception("Internal error");
}
}
// Add node supplies.
for (int i = 0; i < supplies.Length; ++i)
{
minCostFlow.SetNodeSupply(i, supplies[i]);
}
// [END constraints]
// [START solve]
// Find the min cost flow.
MinCostFlow.Status status = minCostFlow.Solve();
// [END solve]
// [START print_solution]
if (status == MinCostFlow.Status.OPTIMAL)
{
Console.WriteLine("Total cost: " + minCostFlow.OptimalCost());
Console.WriteLine("");
for (int i = 0; i < minCostFlow.NumArcs(); ++i)
{
// Can ignore arcs leading out of source or into sink.
if (minCostFlow.Tail(i) != 0 && minCostFlow.Tail(i) != 11 && minCostFlow.Tail(i) != 12 &&
minCostFlow.Head(i) != 13)
{
// Arcs in the solution have a flow value of 1. Their start and end nodes
// give an assignment of worker to task.
if (minCostFlow.Flow(i) > 0)
{
Console.WriteLine("Worker " + minCostFlow.Tail(i) + " assigned to task " + minCostFlow.Head(i) +
" Cost: " + minCostFlow.UnitCost(i));
}
}
}
}
else
{
Console.WriteLine("Solving the min cost flow problem failed.");
Console.WriteLine("Solver status: " + status);
}
// [END print_solution]
}
public List <TimedMove>[] GetCFMAMSolution(MinCostFlow mcmfSolution, long mcmfTime, bool printPath = false)
{
Stack <NFReducerNode>[] paths = new Stack <NFReducerNode> [startPositions.Length];
Stack <NFReducerNode[]>[] nodesForEachTime = new Stack <NFReducerNode[]> [this.T + 1];
for (int i = 0; i < nodesForEachTime.Length; i++)
{
nodesForEachTime[i] = new Stack <NFReducerNode[]>();
}
// Sorting each move to it's time
for (int i = 0; i < outputProblem.numArcs; i++)
{
long cost = mcmfSolution.Flow(i) * mcmfSolution.UnitCost(i);
if (cost != 0)
{
NFReducerNode fromNode = GetNode(mcmfSolution.Tail(i));
NFReducerNode toNode = GetNode(mcmfSolution.Head(i));
if (T - fromNode.nodeTime == 0)
{
NFReducerNode[] nodesStartArray = { null, fromNode };
nodesForEachTime[0].Push(nodesStartArray);
}
NFReducerNode[] nodesArray = { fromNode, toNode };
nodesForEachTime[T - toNode.nodeTime].Push(nodesArray);
}
}
// Inserting start nodes to each agent path
int startNodesCounter = 0;
foreach (NFReducerNode[] startNode in nodesForEachTime[0])
{
paths[startNodesCounter] = new Stack <NFReducerNode>();
paths[startNodesCounter].Push(startNode[1]);
startNodesCounter++;
}
// Searching agents that started on the meeting points
for (int i = 0; i < paths.Length; i++)
{
if (paths[i] == null)
{
if (isAgentStartedOnGoalNode())
{
paths[i] = new Stack <NFReducerNode>();
paths[i].Push(new NFReducerNode(0, goalState.x, goalState.y));
}
else
{
paths = paths.Where(p => p != null).ToArray();
}
break;
}
}
// Adding each node of each agent to his path
for (int i = 1; i < nodesForEachTime.Length; i++)
{
while (nodesForEachTime[i].Count != 0)
{
NFReducerNode[] move = nodesForEachTime[i].Pop();
for (int j = 0; j < paths.Length; j++)
{
NFReducerNode lastNode = paths[j].Peek();
if (lastNode.x == move[0].x && lastNode.y == move[0].y && lastNode.nodeTime == move[0].nodeTime)
{
paths[j].Push(move[1]);
break;
}
}
}
}
List <TimedMove>[] agentPaths = new List <TimedMove> [startPositions.Length];
for (int i = 0; i < agentPaths.Length; i++)
{
agentPaths[i] = new List <TimedMove>();
}
for (int i = 0; i < paths.Length; i++)
{
int pathLength = paths[i].Count;
while (paths[i].Count != 0)
{
int nodeTime = pathLength - paths[i].Count;
NFReducerNode node = paths[i].Pop();
agentPaths[i].Insert(0, new TimedMove(node.x, node.y, Move.Direction.NO_DIRECTION, nodeTime));
}
}
return(agentPaths);
}
