// Different strategy for JoinTwo
// The column obtained by joining two partial solutions is the bitwise AND of the columns corresponding to both solutions
// Exploits this to attempt to speed up RBA
public Dictionary <PartialSolution, int> JoinTwoIncremental(TDNode bag, List <int> verticesInvolved, Dictionary <PartialSolution, int> leftTable, Dictionary <PartialSolution, int> rightTable)
{
Dictionary <PartialSolution, int> newTable = new Dictionary <PartialSolution, int>();
RankBased irbL = new RankBased(leftTable.First().Key.Subset);
RankBased irbR = new RankBased(rightTable.First().Key.Subset);
Tuple <KeyValuePair <PartialSolution, int>, Vector <uint>[]>[] leftSolutions = leftTable.OrderBy((kvp2) => kvp2.Value).Select((s) => Tuple.Create(s, irbL.GetColumn(s.Key))).ToArray();
Tuple <KeyValuePair <PartialSolution, int>, Vector <uint>[]>[] rightSolutions = rightTable.OrderBy((kvp2) => kvp2.Value).Select((s) => Tuple.Create(s, irbR.GetColumn(s.Key))).ToArray();
if (leftSolutions.Length > (1 << (verticesInvolved.Count - 1)))
{
for (int i = 0; i < leftSolutions.Length; i++)
{
if (!irbL.AddSolution(leftSolutions[i].Item1.Key, leftSolutions[i].Item2))
{
leftSolutions[i] = null;
}
}
}
if (rightSolutions.Length > (1 << (verticesInvolved.Count - 1)))
{
for (int i = 0; i < rightSolutions.Length; i++)
{
if (!irbR.AddSolution(rightSolutions[i].Item1.Key, rightSolutions[i].Item2))
{
rightSolutions[i] = null;
}
}
}
leftSolutions = leftSolutions.Where((s) => s != null).ToArray();
rightSolutions = rightSolutions.Where((s) => s != null).ToArray();
Tuple <PartialSolution, PartialSolution, Vector <uint>[], Vector <uint>[], int>[] joinedSolutions = new Tuple <PartialSolution, PartialSolution, Vector <uint>[], Vector <uint>[], int> [leftSolutions.Length * rightSolutions.Length];
int pos = 0;
foreach (Tuple <KeyValuePair <PartialSolution, int>, Vector <uint>[]> ls in leftSolutions)
{
foreach (Tuple <KeyValuePair <PartialSolution, int>, Vector <uint>[]> rs in rightSolutions)
{
joinedSolutions[pos++] = Tuple.Create(ls.Item1.Key, rs.Item1.Key, ls.Item2, rs.Item2, ls.Item1.Value + rs.Item1.Value);
}
}
joinedSolutions = joinedSolutions.OrderBy((s) => s.Item5).ToArray();
//leftTable = RankBasedReduce(leftTable, 1);
//rightTable = RankBasedReduce(rightTable, 1);
RankBased irbJoined = new RankBased(leftTable.First().Key.Subset);
HashSet <PartialSolution> psSeen = new HashSet <PartialSolution>();
foreach (Tuple <PartialSolution, PartialSolution, Vector <uint>[], Vector <uint>[], int> pair in joinedSolutions)
{
VertexSubset newSubset = VertexSubset.Create(bag, pair.Item1.Subset.LocalSubset, pair.Item1.Subset, pair.Item2.Subset);
PartialSolution newSol = new PartialSolution(newSubset, pair.Item1);
bool good = true;
foreach (int i in verticesInvolved)
{
byte rep = pair.Item2.Find(i);
if (rep == i)
{
continue;
}
if (newSol.Find(i) == newSol.Find(rep))
{
good = false; break;
}
newSol.Union(i, rep);
}
if (!good || !psSeen.Add(newSol))
{
continue;
}
Vector <uint>[] joinedColumn = RankBased.GetArray();
RankBased.AND(pair.Item3, pair.Item4, joinedColumn, irbJoined.rowCountVector);
if (!irbJoined.AddSolution(newSol, joinedColumn))
{
RankBased.ReleaseArray(joinedColumn);
continue;
}
newTable.Add(newSol, pair.Item5);
}
RankBased.ClearPool();
return(newTable);
}
// Splits up joins into binary joins in a heuristically efficient way
public void DeconstructJoins(TDNode parent)
{
IEnumerable <TDNode> children = Adj.Where((n) => n != parent);
foreach (TDNode child in children)
{
child.DeconstructJoins(this);
}
if (children.Count() <= 2)
{
return;
}
List <Tuple <int, TDNode> > toJoin = new List <Tuple <int, TDNode> >();
foreach (TDNode child in children)
{
int code = 0;
foreach (Vertex v in child.Bag)
{
code |= 1 << v.Color;
}
toJoin.Add(Tuple.Create(code, child));
child.Adj.Remove(this);
}
this.Adj.Clear();
Adj.Add(parent);
while (toJoin.Count > 2 || (toJoin.Count == 2 && (toJoin[0].Item1 | toJoin[1].Item1).BitCount() < Bag.Length))
{
int min = int.MaxValue; Tuple <int, TDNode> left = null, right = null;
for (int i = 0; i < toJoin.Count; i++)
{
for (int j = i + 1; j < toJoin.Count; j++)
{
if ((toJoin[i].Item1 | toJoin[j].Item1).BitCount() < min)
{
min = (toJoin[i].Item1 | toJoin[j].Item1).BitCount();
left = toJoin[i]; right = toJoin[j];
}
}
}
toJoin.Remove(left); toJoin.Remove(right);
TDNode newNode = new TDNode((left.Item1 | right.Item1).BitCount(), ParentDecomposition, VertexByColor.Length);
toJoin.Add(Tuple.Create(left.Item1 | right.Item1, newNode));
newNode.Adj.Add(left.Item2);
newNode.Adj.Add(right.Item2);
left.Item2.Adj.Add(newNode);
right.Item2.Adj.Add(newNode);
ParentDecomposition.Nodes.Add(newNode);
int c = 0;
for (int i = 0; i < VertexByColor.Length; i++)
{
if (left.Item2.VertexByColor[i] != null)
{
newNode.Bag[c++] = left.Item2.VertexByColor[i];
newNode.VertexByColor[i] = left.Item2.VertexByColor[i];
}
else if (right.Item2.VertexByColor[i] != null)
{
newNode.Bag[c++] = right.Item2.VertexByColor[i];
newNode.VertexByColor[i] = right.Item2.VertexByColor[i];
}
}
}
this.Adj.Add(toJoin[0].Item2);
toJoin[0].Item2.Adj.Add(this);
if (toJoin.Count > 1)
{
this.Adj.Add(toJoin[1].Item2);
toJoin[1].Item2.Adj.Add(this);
}
}