/// <summary>
/// Parsing of the CDKRGraph. This is the recursive method
/// to perform a query. The method will recursively
/// parse the CDKRGraph thru connected nodes and visiting the
/// CDKRGraph using allowed adjacency relationship.
/// </summary>
/// <param name="traversed">node already parsed</param>
/// <param name="extension">possible extension node (allowed neighbors)</param>
/// <param name="forbidden">node forbidden (set of node incompatible with the current solution)</param>
private void ParseRec(BitArray traversed, BitArray extension, BitArray forbidden)
{
BitArray newTraversed = null;
BitArray newExtension = null;
BitArray newForbidden = null;
BitArray potentialNode = null;
CheckTimeOut();
// if there is no more extension possible we
// have reached a potential new solution
if (BitArrays.IsEmpty(extension))
{
Solution(traversed);
} // carry on with each possible extension
else
{
// calculates the set of nodes that may still
// be reached at this stage (not forbidden)
potentialNode = ((BitArray)GraphBitSet.Clone());
BitArrays.AndNot(potentialNode, forbidden);
potentialNode.Or(traversed);
// checks if we must continue the search
// according to the potential node set
if (MustContinue(potentialNode))
{
// carry on research and update iteration count
NbIteration = NbIteration + 1;
// for each node in the set of possible extension (neighbors of
// the current partial solution, include the node to the solution
// and parse recursively the CDKRGraph with the new context.
for (int x = BitArrays.NextSetBit(extension, 0); x >= 0; x = BitArrays.NextSetBit(extension, x + 1))
{
#if !DEBUG && !TEST
if (IsStop)
{
break;
}
#endif
// evaluates the new set of forbidden nodes
// by including the nodes not compatible with the
// newly accepted node.
newForbidden = (BitArray)forbidden.Clone();
newForbidden.Or((Graph[x]).Forbidden);
// if maxIterator is the first time we are here then
// traversed is empty and we initialize the set of
// possible extensions to the extension of the first
// accepted node in the solution.
if (BitArrays.IsEmpty(traversed))
{
newExtension = (BitArray)((Graph[x]).Extension.Clone());
} // else we simply update the set of solution by
// including the neighbors of the newly accepted node
else
{
newExtension = (BitArray)extension.Clone();
newExtension.Or((Graph[x]).Extension);
}
// extension my not contain forbidden nodes
BitArrays.AndNot(newExtension, newForbidden);
// create the new set of traversed node
// (update current partial solution)
// and add x to the set of forbidden node
// (a node may only appear once in a solution)
newTraversed = (BitArray)traversed.Clone();
newTraversed.Set(x, true);
forbidden.Set(x, true);
// parse recursively the CDKRGraph
ParseRec(newTraversed, newExtension, newForbidden);
}
}
}
}