source: branches/GeneralizedQAP/HeuristicLab.Problems.GeneralizedQuadraticAssignment.Algorithms/3.3/GRASPContext.cs @ 15553

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2017 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Threading;
using HeuristicLab.Common;
using HeuristicLab.Core;
using HeuristicLab.Data;
using HeuristicLab.Optimization;
using HeuristicLab.Parameters;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Random;

namespace HeuristicLab.Problems.GeneralizedQuadraticAssignment.Algorithms.GRASP {
  [Item("GRASP+PR (GQAP) Context", "Context for GRASP+PR (GQAP).")]
  [StorableClass]
  public sealed class GRASPContext : ParameterizedNamedItem, IExecutionContext {
    
    private IExecutionContext parent;
    public IExecutionContext Parent {
      get { return parent; }
      set { parent = value; }
    }

    [Storable]
    private IScope scope;
    public IScope Scope {
      get { return scope; }
      private set { scope = value; }
    }

    IKeyedItemCollection<string, IParameter> IExecutionContext.Parameters {
      get { return Parameters; }
    }

    [Storable]
    private IValueParameter<GQAP> problem;
    public GQAP Problem {
      get { return problem.Value; }
      set { problem.Value = value; }
    }
    public bool Maximization {
      get { return Problem.Maximization; }
    }

    [Storable]
    private IValueParameter<BoolValue> initialized;
    public bool Initialized {
      get { return initialized.Value.Value; }
      set { initialized.Value.Value = value; }
    }

    [Storable]
    private IValueParameter<IntValue> iterations;
    public int Iterations {
      get { return iterations.Value.Value; }
      set { iterations.Value.Value = value; }
    }

    [Storable]
    private IValueParameter<IntValue> evaluatedSolutions;
    public int EvaluatedSolutions {
      get { return evaluatedSolutions.Value.Value; }
      set { evaluatedSolutions.Value.Value = value; }
    }

    [Storable]
    private IValueParameter<DoubleValue> bestQuality;
    public double BestQuality {
      get { return bestQuality.Value.Value; }
      set { bestQuality.Value.Value = value; }
    }

    [Storable]
    private IValueParameter<GQAPSolution> bestSolution;
    public GQAPSolution BestSolution {
      get { return bestSolution.Value; }
      set { bestSolution.Value = value; }
    }

    [Storable]
    private IValueParameter<IntValue> localSearchEvaluations;
    public int LocalSearchEvaluations {
      get { return localSearchEvaluations.Value.Value; }
      set { localSearchEvaluations.Value.Value = value; }
    }
    
    [Storable]
    private IValueParameter<IRandom> random;
    public IRandom Random {
      get { return random.Value; }
      set { random.Value = value; }
    }

    public IEnumerable<ISingleObjectiveSolutionScope<GQAPSolution>> Population {
      get { return scope.SubScopes.OfType<ISingleObjectiveSolutionScope<GQAPSolution>>(); }
    }
    public void AddToPopulation(ISingleObjectiveSolutionScope<GQAPSolution> solScope) {
      scope.SubScopes.Add(solScope);
    }
    public void ReplaceAtPopulation(int index, ISingleObjectiveSolutionScope<GQAPSolution> solScope) {
      scope.SubScopes[index] = solScope;
    }
    public ISingleObjectiveSolutionScope<GQAPSolution> AtPopulation(int index) {
      return scope.SubScopes[index] as ISingleObjectiveSolutionScope<GQAPSolution>;
    }
    public void SortPopulation() {
      scope.SubScopes.Replace(scope.SubScopes.OfType<ISingleObjectiveSolutionScope<GQAPSolution>>().OrderBy(x => Maximization ? -x.Fitness : x.Fitness).ToList());
    }
    public int PopulationCount {
      get { return scope.SubScopes.Count; }
    }
    
    [StorableConstructor]
    private GRASPContext(bool deserializing) : base(deserializing) { }
    private GRASPContext(GRASPContext original, Cloner cloner)
      : base(original, cloner) {
      scope = cloner.Clone(original.scope);
      problem = cloner.Clone(original.problem);
      initialized = cloner.Clone(original.initialized);
      iterations = cloner.Clone(original.iterations);
      evaluatedSolutions = cloner.Clone(original.evaluatedSolutions);
      bestQuality = cloner.Clone(original.bestQuality);
      bestSolution = cloner.Clone(original.bestSolution);
      localSearchEvaluations = cloner.Clone(original.localSearchEvaluations);
      random = cloner.Clone(original.random);
    }
    public GRASPContext() : this("GRASP+PR (GQAP) Context") { }
    public GRASPContext(string name) : base(name) {
      scope = new Scope("Global");

      Parameters.Add(problem = new ValueParameter<GQAP>("Problem"));
      Parameters.Add(initialized = new ValueParameter<BoolValue>("Initialized", new BoolValue(false)));
      Parameters.Add(iterations = new ValueParameter<IntValue>("Iterations", new IntValue(0)));
      Parameters.Add(evaluatedSolutions = new ValueParameter<IntValue>("EvaluatedSolutions", new IntValue(0)));
      Parameters.Add(bestQuality = new ValueParameter<DoubleValue>("BestQuality", new DoubleValue(double.NaN)));
      Parameters.Add(bestSolution = new ValueParameter<GQAPSolution>("BestFoundSolution"));
      Parameters.Add(localSearchEvaluations = new ValueParameter<IntValue>("LocalSearchEvaluations", new IntValue(0)));
      Parameters.Add(random = new ValueParameter<IRandom>("Random", new MersenneTwister()));
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new GRASPContext(this, cloner);
    }

    public ISingleObjectiveSolutionScope<GQAPSolution> ToScope(GQAPSolution code, double fitness = double.NaN) {
      var name = Problem.Encoding.Name;
      var scope = new SingleObjectiveSolutionScope<GQAPSolution>(code,
        name + "Solution", fitness, Problem.Evaluator.QualityParameter.ActualName) {
        Parent = Scope
      };
      scope.Variables.Add(new Variable(name, code.Assignment));
      scope.Variables.Add(new Variable("Evaluation", code.Evaluation));
      return scope;
    }

    public double Evaluate(GQAPSolution solution, CancellationToken token) {
      var solScope = ToScope(solution);
      Evaluate(solScope, token);
      return solScope.Fitness;
    }

    public void Evaluate(ISingleObjectiveSolutionScope<GQAPSolution> solScope, CancellationToken token) {
      var pdef = Problem as ISingleObjectiveProblemDefinition;
      if (pdef != null) {
        var ind = new SingleEncodingIndividual(pdef.Encoding, solScope);
        solScope.Fitness = pdef.Evaluate(ind, Random);
      } else {
        RunOperator(Problem.Evaluator, solScope, token);
      }
    }

    public GRASPSolutionContext CreateSingleSolutionContext(ISingleObjectiveSolutionScope<GQAPSolution> solution) {
      return new GRASPSolutionContext(this, solution);
    }

    public void IncrementEvaluatedSolutions(int byEvaluations) {
      if (byEvaluations < 0) throw new ArgumentException("Can only increment and not decrement evaluated solutions.");
      EvaluatedSolutions += byEvaluations;
    }
    
    private static void ExecuteAlgorithm(IAlgorithm algorithm) {
      using (var evt = new AutoResetEvent(false)) {
        EventHandler exeStateChanged = (o, args) => {
          if (algorithm.ExecutionState != ExecutionState.Started)
            evt.Set();
        };
        algorithm.ExecutionStateChanged += exeStateChanged;
        if (algorithm.ExecutionState != ExecutionState.Prepared) {
          algorithm.Prepare(true);
          evt.WaitOne();
        }
        algorithm.Start();
        evt.WaitOne();
        algorithm.ExecutionStateChanged -= exeStateChanged;
      }
    }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public bool IsBetter(ISingleObjectiveSolutionScope<GQAPSolution> a, ISingleObjectiveSolutionScope<GQAPSolution> b) {
      return IsBetter(a.Fitness, b.Fitness);
    }
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    public bool IsBetter(double a, double b) {
      return double.IsNaN(b) && !double.IsNaN(a)
        || Maximization && a > b
        || !Maximization && a < b;
    }

    #region IExecutionContext members
    public IAtomicOperation CreateOperation(IOperator op) {
      return new Core.ExecutionContext(this, op, Scope);
    }

    public IAtomicOperation CreateOperation(IOperator op, IScope s) {
      return new Core.ExecutionContext(this, op, s);
    }

    public IAtomicOperation CreateChildOperation(IOperator op) {
      return new Core.ExecutionContext(this, op, Scope);
    }

    public IAtomicOperation CreateChildOperation(IOperator op, IScope s) {
      return new Core.ExecutionContext(this, op, s);
    }
    #endregion

    #region Engine Helper
    public void RunOperator(IOperator op, IScope scope, CancellationToken cancellationToken) {
      var stack = new Stack<IOperation>();
      stack.Push(CreateChildOperation(op, scope));

      while (stack.Count > 0) {
        cancellationToken.ThrowIfCancellationRequested();

        var next = stack.Pop();
        if (next is OperationCollection) {
          var coll = (OperationCollection)next;
          for (int i = coll.Count - 1; i >= 0; i--)
            if (coll[i] != null) stack.Push(coll[i]);
        } else if (next is IAtomicOperation) {
          var operation = (IAtomicOperation)next;
          try {
            next = operation.Operator.Execute((IExecutionContext)operation, cancellationToken);
          } catch (Exception ex) {
            stack.Push(operation);
            if (ex is OperationCanceledException) throw ex;
            else throw new OperatorExecutionException(operation.Operator, ex);
          }
          if (next != null) stack.Push(next);
        }
      }
    }
    #endregion
  }

  [Item("GRASP+PR (GQAP) SolutionContext", "SolutionContext for GRASP+PR (GQAP).")]
  [StorableClass]
  public sealed class GRASPSolutionContext : ParameterizedNamedItem, IExecutionContext {

    private GRASPContext parent;
    public IExecutionContext Parent {
      get { return parent; }
      set { throw new InvalidOperationException("Cannot set the parent of a single-solution context."); }
    }

    [Storable]
    private ISingleObjectiveSolutionScope<GQAPSolution> scope;
    public IScope Scope {
      get { return scope; }
    }

    IKeyedItemCollection<string, IParameter> IExecutionContext.Parameters {
      get { return Parameters; }
    }

    public GQAP Problem {
      get { return parent.Problem; }
    }
    public bool Maximization {
      get { return parent.Maximization; }
    }

    public double BestQuality {
      get { return parent.BestQuality; }
      set { parent.BestQuality = value; }
    }

    public GQAPSolution BestSolution {
      get { return parent.BestSolution; }
      set { parent.BestSolution = value; }
    }

    public IRandom Random {
      get { return parent.Random; }
    }

    [Storable]
    private IValueParameter<IntValue> evaluatedSolutions;
    public int EvaluatedSolutions {
      get { return evaluatedSolutions.Value.Value; }
      set { evaluatedSolutions.Value.Value = value; }
    }

    [Storable]
    private IValueParameter<IntValue> iterations;
    public int Iterations {
      get { return iterations.Value.Value; }
      set { iterations.Value.Value = value; }
    }

    [StorableConstructor]
    private GRASPSolutionContext(bool deserializing) : base(deserializing) { }
    private GRASPSolutionContext(GRASPSolutionContext original, Cloner cloner)
      : base(original, cloner) {
      scope = cloner.Clone(original.scope);
      evaluatedSolutions = cloner.Clone(original.evaluatedSolutions);
      iterations = cloner.Clone(original.iterations);
    }
    public GRASPSolutionContext(GRASPContext baseContext, ISingleObjectiveSolutionScope<GQAPSolution> solution) {
      parent = baseContext;
      scope = solution;

      Parameters.Add(evaluatedSolutions = new ValueParameter<IntValue>("EvaluatedSolutions", new IntValue(0)));
      Parameters.Add(iterations = new ValueParameter<IntValue>("Iterations", new IntValue(0)));
    }

    public override IDeepCloneable Clone(Cloner cloner) {
      return new GRASPSolutionContext(this, cloner);
    }

    public void IncrementEvaluatedSolutions(int byEvaluations) {
      if (byEvaluations < 0) throw new ArgumentException("Can only increment and not decrement evaluated solutions.");
      EvaluatedSolutions += byEvaluations;
    }
    public double Evaluate(GQAPSolution solution, CancellationToken token) {
      return parent.Evaluate(solution, token);
    }

    public void Evaluate(ISingleObjectiveSolutionScope<GQAPSolution> solScope, CancellationToken token) {
      parent.Evaluate(solScope, token);
    }

    #region IExecutionContext members
    public IAtomicOperation CreateOperation(IOperator op) {
      return new Core.ExecutionContext(this, op, Scope);
    }

    public IAtomicOperation CreateOperation(IOperator op, IScope s) {
      return new Core.ExecutionContext(this, op, s);
    }

    public IAtomicOperation CreateChildOperation(IOperator op) {
      return new Core.ExecutionContext(this, op, Scope);
    }

    public IAtomicOperation CreateChildOperation(IOperator op, IScope s) {
      return new Core.ExecutionContext(this, op, s);
    }
    #endregion
  }
}