private double SingleSwap([NotNull, ItemNotNull] ICollection <SwapPair> swaps)
{
SwapPair maxPair = null;
double maxGain = double.MinValue;
foreach (TVertex vertexFromA in _unSwappedSetA)
{
foreach (TVertex vertexFromB in _unSwappedSetB)
{
bool foundEdge = FindEdge(vertexFromA, vertexFromB, out TEdge edge);
double edgeCost = foundEdge ? edge.Tag : 0.0;
double gain = GetVertexCost(vertexFromA) + GetVertexCost(vertexFromB) - 2 * edgeCost;
if (gain > maxGain)
{
maxPair = new SwapPair(vertexFromA, vertexFromB);
maxGain = gain;
}
}
}
if (maxPair is null)
{
throw new InvalidOperationException("Must find a swap.");
}
SwapVertices(_vertexSetA, maxPair.Vertex1, _vertexSetB, maxPair.Vertex2);
swaps.Add(maxPair);
_unSwappedSetA.Remove(maxPair.Vertex1);
_unSwappedSetB.Remove(maxPair.Vertex2);
return(GetCutCost());
}
private Partition <TVertex> DoAllSwaps()
{
var swaps = new List <SwapPair>();
double minCost = double.MaxValue;
int minId = -1;
for (int i = 0; i < _partitionSize; ++i)
{
double cost = SingleSwap(swaps);
if (cost < minCost)
{
minCost = cost;
minId = i;
}
}
// Back to swap step with min cut cost
while (swaps.Count - 1 > minId)
{
SwapPair pair = swaps.Last();
swaps.Remove(pair);
SwapVertices(_vertexSetA, pair.Vertex2, _vertexSetB, pair.Vertex1);
}
return(new Partition <TVertex>(_vertexSetA, _vertexSetB, minCost));
}
/// <summary>Delegate method invoked by dcSwap.</summary>
private void ExecuteSwap()
{
if (CanExecuteSwap())
{
Drive SwapDrive = _SourceDrive;
_SourceDrive = _DestinationDrive;
_DestinationDrive = SwapDrive;
string sSwapDirectory = _sSourceDirectory;
_sSourceDirectory = _sDestinationDirectory;
_sDestinationDirectory = sSwapDirectory;
_SourceDrive.isSource = true;
_DestinationDrive.isSource = false;
foreach (PairOfFiles SwapPair in _ltPairs)
{
SwapPair.SwapSourceAndDestination();
}
RequeryDisplayedPairs(true);
NotifyPropertyChanged("sSourceDirectory");
NotifyPropertyChanged("sDestinationDirectory");
}
}
static IEnumerable <SwapPair> PossibleSwaps(Matchspace space)
{
var surfaceNoMatch = from Matchable match in space.grid
where !match.Hidden() && !match.AnyMatch()
select match;
foreach (Matchable first in surfaceNoMatch.Where(first => first.AnyAlmost()))
{
foreach (Matchable second in surfaceNoMatch)
{
if (SwapPair.MatchingSwap(first, second))
{
yield return(new SwapPair(first, second));
}
}
}
}
