public override int[] GetPath(int n, IMeasure measure)
{
var baseState = new GenerationState
{
C = new double[n,n],
Edges = new List<Edge>(n),
N = n,
VertexSet = new int[n]
};
baseState.C = measure.GetMatrix();
for (int i = 0; i < n; i++)
{
baseState.C[i, i] = Inf;
}
baseState.J = ReductMatrix(n, baseState.C);
for (int i = 0; i < n; i++)
{
baseState.VertexSet[i] = i;
}
var queue = new PriorityQueue<GenerationState>((a, b) => -a.J.CompareTo(b.J));
queue.Enqueue(baseState);
while (queue.Count > 0)
{
var current = queue.Dequeue();
if (current.Edges.Count == n - 1)
{
var result = GetResult(n, current.Edges);
return result;
}
Process(current, queue);
}
throw new ApplicationException("Path not found");
}
private void Process(GenerationState state, PriorityQueue<GenerationState> queue)
{
//state.J = ReductMatrix(state.N, state.C);
int bestI = 0, bestJ = 0;
double bestMax = -1;
int n = state.N;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
if (state.C[i, j] < Eps)
{
double m = GetMinSum(n, state.C, i, j);
if (bestMax < m)
{
bestMax = m;
bestI = i;
bestJ = j;
}
}
}
}
if (state.C[bestI, bestJ] > InfBound)
{
return;
}
// get state 1
var stateWithoutEdge = new GenerationState
{
N = state.N,
C = new double[n,n],
Edges = state.Edges,
VertexSet = state.VertexSet
};
Array.Copy(state.C, stateWithoutEdge.C, state.C.Length);
stateWithoutEdge.C[bestI, bestJ] = Inf; // TODO: Remove j -> i ??
double r2 = ReductMatrix(n, stateWithoutEdge.C);
stateWithoutEdge.J = state.J + r2;
// get state 2
var stateWithEdge = new GenerationState
{
N = state.N,
C = new double[n, n],
Edges = new List<Edge>(state.Edges),
VertexSet = new int[n]
};
Array.Copy(state.C, stateWithEdge.C, state.C.Length);
for (int i = 0; i < n; i++)
{
stateWithEdge.C[i, bestJ] = Inf;
}
for (int j = 0; j < n; j++)
{
stateWithEdge.C[bestI, j] = Inf;
}
stateWithEdge.C[bestJ, bestI] = Inf;
Array.Copy(state.VertexSet, stateWithEdge.VertexSet, n);
int c1 = stateWithEdge.VertexSet[bestI];
int c2 = stateWithEdge.VertexSet[bestJ];
for (int i = 0; i < n; i++)
{
if (stateWithEdge.VertexSet[i] == c1)
{
for (int j = 0; j < n; j++)
{
if (stateWithEdge.VertexSet[j] == c2)
{
stateWithEdge.C[i, j] = Inf;
stateWithEdge.C[j, i] = Inf;
}
}
}
}
for (int i = 0; i < n; i++)
{
if (stateWithEdge.VertexSet[i] == c2)
{
stateWithEdge.VertexSet[i] = c1;
}
}
double r1 = ReductMatrix(n, stateWithEdge.C);
stateWithEdge.J = state.J + r1;
stateWithEdge.Edges.Add(new Edge(bestI, bestJ));
queue.Enqueue(stateWithEdge);
queue.Enqueue(stateWithoutEdge);
return;
}
