// Copyright (C) 2004, 2006 International Business Machines and others.
// All Rights Reserved.
// This code is published under the Eclipse Public License.
//
// Authors:  Carl Laird, Andreas Waechter     IBM    2004-08-13

#ifndef __IP_AUGRESTOSYSTEMSOLVER_HPP__
#define __IP_AUGRESTOSYSTEMSOLVER_HPP__

#include "IpAugSystemSolver.hpp"

namespace Ipopt
{

/** Class that converts an augmented system with compound restoration
 *  pieces into a smaller "pivoted" system to be solved with an
 *  existing AugSystemSolver.
 *
 *  This is really a decorator that changes
 *  the behavior of the AugSystemSolver to account for the known structure
 *  of the restoration phase.
 */
class AugRestoSystemSolver: public AugSystemSolver
{
public:
   /**@name Constructors/Destructors */
   ///@{
   /** Constructor.
    *
    *  Here, orig_aug_solver is the object for solving
    *  the original augmented system.  The flag
    *  skip_orig_aug_solver_init indicates, if the initialization
    *  call (to Initialize) should be skipped; this flag will usually
    *  be true, so that the symbolic factorization of the main
    *  algorithm will be used.
    */
   AugRestoSystemSolver(
      AugSystemSolver& orig_aug_solver,
      bool             skip_orig_aug_solver_init = true
   );

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

   /** overloaded from AlgorithmStrategyObject */
   bool InitializeImpl(
      const OptionsList& options,
      const std::string& prefix
   );

   /** Translate the augmented system (in the full space of the
    *  restoration variables) into the smaller space of the original
    *  variables.
    */
   virtual ESymSolverStatus Solve(
      const SymMatrix* W,
      double           W_factor,
      const Vector*    D_x,
      double           delta_x,
      const Vector*    D_s,
      double           delta_s,
      const Matrix*    J_c,
      const Vector*    D_c,
      double           delta_c,
      const Matrix*    J_d,
      const Vector*    D_d,
      double           delta_d,
      const Vector&    rhs_x,
      const Vector&    rhs_s,
      const Vector&    rhs_c,
      const Vector&    rhs_d,
      Vector&          sol_x,
      Vector&          sol_s,
      Vector&          sol_c,
      Vector&          sol_d,
      bool             check_NegEVals,
      Index            numberOfNegEVals
   );

   /** Returns the number of negative eigenvalues from the original
    *  augmented system call
    */
   virtual Index NumberOfNegEVals() const
   {
      return orig_aug_solver_->NumberOfNegEVals();
   }

   /** Query whether inertia is computed by linear solver.
    *
    * @return true, if linear solver provides inertia
    */
   virtual bool ProvidesInertia() const
   {
      return orig_aug_solver_->ProvidesInertia();
   }

   /** Request to increase quality of solution for next solve.
    *
    *  Ask underlying linear solver to increase quality of solution for
    *  the next solve (e.g. increase pivot tolerance).  Returns
    *  false, if this is not possible (e.g. maximal pivot tolerance
    *  already used.)
    */
   virtual bool IncreaseQuality()
   {
      return orig_aug_solver_->IncreaseQuality();
   }

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 */
   AugRestoSystemSolver();

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

   /** Default Assignment Operator */
   void operator=(
      const AugRestoSystemSolver&
   );
   ///@}

   /**@name Caches for some of the necessary calculated quantities */
   ///@{
   CachedResults<SmartPtr<Vector> > neg_omega_c_plus_D_c_cache_;
   CachedResults<SmartPtr<Vector> > neg_omega_d_plus_D_d_cache_;
   CachedResults<SmartPtr<Vector> > sigma_tilde_n_c_inv_cache_;
   CachedResults<SmartPtr<Vector> > sigma_tilde_p_c_inv_cache_;
   CachedResults<SmartPtr<Vector> > sigma_tilde_n_d_inv_cache_;
   CachedResults<SmartPtr<Vector> > sigma_tilde_p_d_inv_cache_;
   CachedResults<SmartPtr<Vector> > d_x_plus_wr_d_cache_;
   CachedResults<SmartPtr<Vector> > rhs_cR_cache_;
   CachedResults<SmartPtr<Vector> > rhs_dR_cache_;
   ///@}

   /**@name Methods to calculate the cached quantities */
   ///@{
   SmartPtr<const Vector> Neg_Omega_c_plus_D_c(
      const SmartPtr<const Vector>& sigma_tilde_n_c_inv,
      const SmartPtr<const Vector>& sigma_tilde_p_c_inv,
      const Vector*                 D_c,
      const Vector&                 any_vec_in_c
   );

   SmartPtr<const Vector> Neg_Omega_d_plus_D_d(
      const Matrix&                 Pd_L,
      const SmartPtr<const Vector>& sigma_tilde_n_d_inv,
      const Matrix&                 neg_Pd_U,
      const SmartPtr<const Vector>& sigma_tilde_p_d_inv,
      const Vector*                 D_d,
      const Vector&                 any_vec_in_d
   );

   /** Sigma tilde is the sum of Sigma and delta_x times the identity */
   SmartPtr<const Vector> Sigma_tilde_n_c_inv(
      const SmartPtr<const Vector>& sigma_tilde_n_c,
      Number                        delta_x,
      const Vector&                 any_vec_in_n_c
   );

   SmartPtr<const Vector> Sigma_tilde_p_c_inv(
      const SmartPtr<const Vector>& sigma_tilde_p_c,
      Number                        delta_x,
      const Vector&                 any_vec_in_p_c
   );

   SmartPtr<const Vector> Sigma_tilde_n_d_inv(
      const SmartPtr<const Vector>& sigma_tilde_n_d,
      Number                        delta_x,
      const Vector&                 any_vec_in_n_d
   );

   SmartPtr<const Vector> Sigma_tilde_p_d_inv(
      const SmartPtr<const Vector>& sigma_tilde_p_d,
      Number                        delta_x,
      const Vector&                 any_vec_in_p_d
   );

   SmartPtr<const Vector> D_x_plus_wr_d(
      const SmartPtr<const Vector>& CD_x0,
      Number                        factor,
      const Vector&                 wr_d
   );

   SmartPtr<const Vector> Rhs_cR(
      const Vector&                 rhs_c,
      const SmartPtr<const Vector>& sigma_tilde_n_c_inv,
      const Vector&                 rhs_n_c,
      const SmartPtr<const Vector>& sigma_tilde_p_c_inv,
      const Vector&                 rhs_p_c
   );

   SmartPtr<const Vector> Rhs_dR(
      const Vector&                 rhs_d,
      const SmartPtr<const Vector>& sigma_tilde_n_d_inv,
      const Vector&                 rhs_n_d,
      const Matrix&                 pd_L,
      const SmartPtr<const Vector>& sigma_tilde_p_d_inv,
      const Vector&                 rhs_p_d,
      const Matrix&                 pd_U
   );
   ///@}

   SmartPtr<AugSystemSolver> orig_aug_solver_;
   bool skip_orig_aug_solver_init_;
};

} // namespace Ipopt

#endif
