private SolverNode(IEnumerable<AbstractConstraint> constraints,
IDictionary<IVariable, AbstractClosedVariable> closedVariables,
SolverNode origin)
{
_debugOrigin = origin;
if (origin != null) {
origin._debugSuccessors++;
}
//var foldingVisitor = new ConstantFoldingVisitor();
var foldingVisitor = new PolynomialFoldingVisitor();
_constraints = constraints.Select(c => c.Accept(foldingVisitor, Ig.nore)).ToArray(); // !!!TOARRAY
foreach (var c in _constraints) {
c.SetDebugCreatingNodeIdIfMissing(DebugId);
}
_closedVariables = new SortedDictionary<IVariable, AbstractClosedVariable>(closedVariables);
}
public abstract IEnumerable<SolverNode> SuccessfulMatch(SolverNode current, ScalarConstraint constraint);
private SolverNode(IEnumerable<AbstractConstraint> constraints,
SolverNode origin)
: this(constraints, origin.ClosedVariables, origin)
{
}
public static IEnumerable<SolverNode> SolverStep(IEnumerable<SolverNode> open,
IDictionary<IVariable, VariableWithValue> previousValues,
out SolverNode solutionOrNull,
EvaluationVisitor debugExpectedResults = null)
{
double minRank = open.Min(cs => cs.Rank);
SolverNode selected;
if (debugExpectedResults == null) {
selected = open.First(cs => cs.Rank <= minRank);
} else {
// The debugExpectedResults are intended to steer the solver only on
// nodes that match the expected result!
selected = open.FirstOrDefault(cs =>
cs.Constraints.All(c => DebugIsTrueOrUnknown(c, debugExpectedResults))
);
if (selected == null) {
Debug.WriteLine("---- All open nodes do not match expected results:");
foreach (var node in open) {
Debug.WriteLine(node.DebugToString(debugExpectedResults));
}
throw new InvalidOperationException("No node matches expected results");
}
}
IEnumerable<SolverNode> expanded = selected.Expand( /*previousValues*/).ToArray();
if (!expanded.Any()) {
// Dead node - register in dead nodes.
DebugDeadNodes.Add(selected);
// ????
if (debugExpectedResults != null) {
Debug.WriteLine(".... Constraint state " + selected.DebugToString(debugExpectedResults));
}
}
//IEnumerable<SolverNode> newOpen = open.Except(selected).Concat(expandedSets);
IEnumerable<SolverNode> newOpen = expanded.Concat(open.Except(selected)).ToArray();
// Not really correct: We should also check whether all anchor variables have
// a single value. For the moment, in our tests, we live with this rough check.
solutionOrNull = expanded.FirstOrDefault(cs => cs.IsSolved());
return newOpen;
}