// Copyright (C) 2008, 2011 International Business Machines and others.
// All Rights Reserved.
// This code is published under the Eclipse Public License.
//
// Authors:  Andreas Waechter            IBM    2008-09-05

#ifndef __IPINEXACTNEWTONNORMAL_HPP__
#define __IPINEXACTNEWTONNORMAL_HPP__

#include "IpAlgStrategy.hpp"
#include "IpAugSystemSolver.hpp"
#include "IpInexactCq.hpp"

namespace Ipopt
{
/** Compute the "Newton" normal step from the (slack-scaled)
 *  augmented system.
 */
class InexactNewtonNormalStep: public AlgorithmStrategyObject
{
public:
   /**@name Constructors/Destructors */
   //@{
   /** Constructor */
   InexactNewtonNormalStep(
      SmartPtr<AugSystemSolver> aug_solver
   );

   /** Destructor */
   virtual ~InexactNewtonNormalStep();
   //@}

   virtual bool InitializeImpl(
      const OptionsList& options,
      const std::string& prefix
   );

   /** Method for computing the normal step.
    *
    *  The computed step is
    *  returned as normal_x and normal_s, for the x and s variables,
    *  respectively.  These quantities are not in the original space,
    *  but in the space scaled by the slacks.  If the step cannot be
    *  computed, this method returns false.
    */
   virtual bool ComputeNewtonNormalStep(
      Vector& newton_x,
      Vector& newton_s
   );

   static void RegisterOptions(
      SmartPtr<RegisteredOptions> roptions
   );

protected:
   /** Method to easily access Inexact data */
   InexactData& InexData()
   {
      InexactData& inexact_data = static_cast<InexactData&>(IpData().AdditionalData());
      DBG_ASSERT(dynamic_cast<InexactData*>(&IpData().AdditionalData()));
      return inexact_data;
   }

   /** Method to easily access Inexact calculated quantities */
   InexactCq& InexCq()
   {
      InexactCq& inexact_cq = static_cast<InexactCq&>(IpCq().AdditionalCq());
      DBG_ASSERT(dynamic_cast<InexactCq*>(&IpCq().AdditionalCq()));
      return inexact_cq;
   }

private:
   /**@name Default Compiler Generated Methods
    * (Hidden to avoid implicit creation/calling).
    *
    * These methods are not implemented and
    * we do not want the compiler to implement
    * them for us, so we declare them private
    * and do not define them. This ensures that
    * they will not be implicitly created/called.
    */
   //@{
   /** Default Constructor */
   InexactNewtonNormalStep();

   /** Copy Constructor */
   InexactNewtonNormalStep(
      const InexactNewtonNormalStep&);

   /** Overloaded Assignment Operator */
   void operator=(
      const InexactNewtonNormalStep&
   );
   //@}

   /** Object to be used to solve the augmented system */
   SmartPtr<AugSystemSolver> aug_solver_;
};

} // namespace Ipopt

#endif
