// 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_STDAUGSYSTEMSOLVER_HPP__
#define __IP_STDAUGSYSTEMSOLVER_HPP__

#include "IpAugSystemSolver.hpp"
#include "IpCompoundMatrix.hpp"
#include "IpCompoundSymMatrix.hpp"
#include "IpCompoundVector.hpp"
#include "IpSumSymMatrix.hpp"
#include "IpDiagMatrix.hpp"
#include "IpIdentityMatrix.hpp"

namespace Ipopt
{
/** Solver for the augmented system for triple type matrices.
 *
 *  The current implementation assumes that all matrices are of the
 *  type SymTMatrix, and all vectors are of the type DenseVector.
 */
class StdAugSystemSolver: public AugSystemSolver
{
public:
   /**@name Constructors/Destructors */
   ///@{
   /** Constructor using only a linear solver object */
   StdAugSystemSolver(
      SymLinearSolver& LinSolver
   );

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

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

   /** Set up the augmented system and solve it for a set of given
    *  right hand side - implementation for GenTMatrices and
    *  SymTMatrices.
    */
   virtual ESymSolverStatus MultiSolve(
      const SymMatrix*                      W,
      Number                                W_factor,
      const Vector*                         D_x,
      Number                                delta_x,
      const Vector*                         D_s,
      Number                                delta_s,
      const Matrix*                         J_c,
      const Vector*                         D_c,
      Number                                delta_c,
      const Matrix*                         J_d,
      const Vector*                         D_d,
      Number                                delta_d,
      std::vector<SmartPtr<const Vector> >& rhs_xV,
      std::vector<SmartPtr<const Vector> >& rhs_sV,
      std::vector<SmartPtr<const Vector> >& rhs_cV,
      std::vector<SmartPtr<const Vector> >& rhs_dV,
      std::vector<SmartPtr<Vector> >&       sol_xV,
      std::vector<SmartPtr<Vector> >&       sol_sV,
      std::vector<SmartPtr<Vector> >&       sol_cV,
      std::vector<SmartPtr<Vector> >&       sol_dV,
      bool                                  check_NegEVals,
      Index                                 numberOfNegEVals
   );

   /** Number of negative eigenvalues detected during last solve.
    *
    * This must not be called if the linear solver does not
    * compute this quantities (see ProvidesInertia).
    *
    * @return the number of negative eigenvalues of the
    * most recent factorized matrix
    */
   virtual Index NumberOfNegEVals() const;

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

   /** 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).
    *
    *  @return false, if this is not possible (e.g. maximal
    *  pivot tolerance already used)
    */
   virtual bool 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. */
   StdAugSystemSolver();

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

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

   /** Create the matrix space for the Compound Sym Matrix that
    *  represents the augmented system.
    *
    *  This signifies the "first"
    *  time through and requires all structural knowledge
    */
   void CreateAugmentedSpace(
      const SymMatrix& W,
      const Matrix&    J_c,
      const Matrix&    J_d,
      const Vector&    proto_x,
      const Vector&    proto_s,
      const Vector&    proto_c,
      const Vector&    proto_d
   );

   /** Create the new compound sym matrix that represents the
    *  augmented system.
    *
    *  This is done EVERY time Solve is called
    *  with ANY different information.
    */
   void CreateAugmentedSystem(
      const SymMatrix* W,
      Number           W_factor,
      const Vector*    D_x,
      Number           delta_x,
      const Vector*    D_s,
      Number           delta_s,
      const Matrix&    J_c,
      const Vector*    D_c,
      Number           delta_c,
      const Matrix&    J_d,
      const Vector*    D_d,
      Number           delta_d,
      const Vector&    proto_x,
      const Vector&    proto_s,
      const Vector&    proto_c,
      const Vector&    proto_d
   );

   /** Check the internal tags and decide if the passed variables are
    *  different from what is in the augmented_system_.
    */
   bool AugmentedSystemRequiresChange(
      const SymMatrix* W,
      Number           W_factor,
      const Vector*    D_x,
      Number           delta_x,
      const Vector*    D_s,
      Number           delta_s,
      const Matrix&    J_c,
      const Vector*    D_c,
      Number           delta_c,
      const Matrix&    J_d,
      const Vector*    D_d,
      Number           delta_d
   );

   /** The linear solver object that is to be used to solve the
    *  linear systems.
    */
   SmartPtr<SymLinearSolver> linsolver_;

   /** Spaces for piecing together the augmented system */
   SmartPtr<CompoundSymMatrixSpace> augmented_system_space_;
   SmartPtr<SumSymMatrixSpace> sumsym_space_x_;
   SmartPtr<DiagMatrixSpace> diag_space_x_;
   SmartPtr<DiagMatrixSpace> diag_space_s_;
   SmartPtr<DiagMatrixSpace> diag_space_c_;
   SmartPtr<IdentityMatrixSpace> ident_space_ds_;
   SmartPtr<DiagMatrixSpace> diag_space_d_;

   SmartPtr<CompoundVectorSpace> augmented_vector_space_;

   /**@name Tags and values to track in order to decide whether the
    matrix has to be updated compared to the most recent call of
    the Set method.
    */
   ///@{
   /** Tag for W matrix.
    *
    *  If W has been given to Set as NULL, then this tag is set to 0.
    */
   TaggedObject::Tag w_tag_;

   /** Most recent value of W_factor */
   Number w_factor_;

   /** Tag for D_x vector, representing the diagonal matrix D_x.
    *
    *  If D_x has been given to Set as NULL, then this tag is set to 0.
    */
   TaggedObject::Tag d_x_tag_;

   /** Most recent value of delta_x from Set method */
   Number delta_x_;

   /** Tag for D_s vector, representing the diagonal matrix D_s.
    *
    *  If D_s has been given to Set as NULL, then this tag is set to 0.
    */
   TaggedObject::Tag d_s_tag_;

   /** Most recent value of delta_s from Set method */
   Number delta_s_;

   /** Tag for J_c matrix.
    *
    *  If J_c has been given to Set as NULL, then this tag is set to 0.
    */
   TaggedObject::Tag j_c_tag_;

   /** Tag for D_c vector, representing the diagonal matrix D_c.
    *
    *  If D_c has been given to Set as NULL, then this tag is set to 0.
    */
   TaggedObject::Tag d_c_tag_;

   /** Most recent value of delta_c from set method */
   Number delta_c_;

   /** Tag for J_d matrix.
    *
    *  If J_d has been given to Set as NULL, then this tag is set to 0.
    */
   TaggedObject::Tag j_d_tag_;

   /** Tag for D_d vector, representing the diagonal matrix D_d.
    *
    *  If D_d has been given to Set as NULL, then this tag is set to 0.
    */
   TaggedObject::Tag d_d_tag_;

   /** Most recent value of delta_d from Set method */
   Number delta_d_;

   /** This is the tag of the matrix storing the augmented system.
    *
    *  Since this object owns this matrix, no changes should happen outside.
    *  However, since it is given away as a smart pointer, someone outside
    *  might change it.  For debugging purposes, we now track its tag as
    *  well.
    */
   TaggedObject::Tag augsys_tag_;
   ///@}

   /** The resulting augmented matrix.
    *
    *  This matrix is stored as follows:  First we have the diagonal elements
    *  for the upper left block (for D_W and delta_W), then the elements for
    *  the Hessian W, then the Jacobian A, and finally the diagonal elements
    *  for the lower right block (for D_C and delta_C).
    */
   SmartPtr<CompoundSymMatrix> augmented_system_;

   /** A copy of a previous W used in the augmented_system_.
    *
    *  Since Solve can be called with a NULL W, we keep a copy of the last W
    *  passed to keep the nonzero structure of the augmented_system_ consistent.
    */
   SmartPtr<const SymMatrix> old_w_;

   /** @name Algorithmic parameters */
   ///@{
   /** Flag indicating whether the TNLP with identical structure has
    *  already been solved before.
    */
   bool warm_start_same_structure_;
   ///@}
};

} // namespace Ipopt

#endif
