/// <summary>
/// Solves the clauses and returns a solution.
/// </summary>
/// <param name="status">The solver status.</param>
/// <returns>The solution.</returns>
public Dictionary <string, bool> Solve(out SolverStatus status)
{
// Use Z3 and figure out the variable assignments
using (Context context = new Context())
{
Dictionary <string, Z3Variable> variables = GetVariables(context, this.hard_clauses.Union(this.soft_clauses.Keys));
List <BoolExpr> hard_clauses = GenerateClauses(context, this.hard_clauses, variables);
Dictionary <BoolExpr, uint> soft_clauses = GenerateClauses(context, this.soft_clauses, variables);
Optimize optimize = context.MkOptimize();
optimize.Assert(hard_clauses);
foreach (BoolExpr clause in soft_clauses.Keys)
{
optimize.AssertSoft(clause, soft_clauses[clause], "group");
}
Status solver_status = optimize.Check();
if (solver_status == Status.SATISFIABLE)
{
Dictionary <string, bool> assignments = new Dictionary <string, bool>();
foreach (string variable in variables.Keys)
{
Expr expr = optimize.Model.Evaluate(variables[variable].Positive);
if (expr.BoolValue != Z3_lbool.Z3_L_UNDEF)
{
assignments.Add(variable, expr.BoolValue == Z3_lbool.Z3_L_TRUE ? true : false);
}
}
status = SolverStatus.Satisfiable;
return(assignments);
}
status = SolverStatus.Unsatisfiable;
return(null);
}
}
