// ============================================================================
// ==                                                                        ==
// == AMDiS - Adaptive multidimensional simulations                          ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  crystal growth group                                                  ==
// ==                                                                        ==
// ==  Stiftung caesar                                                       ==
// ==  Ludwig-Erhard-Allee 2                                                 ==
// ==  53175 Bonn                                                            ==
// ==  germany                                                               ==
// ==                                                                        ==
// ============================================================================
// ==                                                                        ==
// ==  http://www.caesar.de/cg/AMDiS                                         ==
// ==                                                                        ==
// ============================================================================

/** \file UmfPackSolver.h */

#ifndef AMDIS_UMFPACKSOLVER_H
#define AMDIS_UMFPACKSOLVER_H

#ifdef HAVE_UMFPACK

#include "OEMSolver.h"
#include "MemoryManager.h"

namespace AMDiS {

  // ============================================================================
  // ===== class UmfPackSolver ==================================================
  // ============================================================================
  
  /**
   * \ingroup Solver
   * 
   * \brief
   * Wrapper for the external UMFPACK solver:
   *   http://www.cise.ufl.edu/research/sparse/umfpack/
   *
   * This is a direct solver for large sparse matrices.
   */
  template<typename VectorType>
  class UmfPackSolver : public OEMSolver<VectorType>
  {
  public:
    MEMORY_MANAGED(UmfPackSolver<VectorType>);

    /** \brief
     * Creator class used in the OEMSolverMap.
     */
    class Creator : public OEMSolverCreator<VectorType>
    {
    public:
      MEMORY_MANAGED(Creator);
      
      virtual ~Creator() {};
      
      /** \brief
       * Returns a new UmfPackSolver object.
       */
      OEMSolver<VectorType>* create() { 
	return NEW UmfPackSolver<VectorType>(this->name); 
      };
    };

    /** \brief
     * constructor
     */
    UmfPackSolver(std::string name);
    
    /** \brief
     * destructor
     */
    ~UmfPackSolver();
  protected:
    /** \brief
     * Implements OEMSolver<VectorType>::init().
     */
    void init() {
      p = this->vectorCreator->create();
      r = this->vectorCreator->create();
    }
    
    /** \brief
     * Implements OEMSolver<VectorType>::exit().
     */
    void exit() {
      this->vectorCreator->free(p);
      this->vectorCreator->free(r);
    }
    
    /** \brief
     * Implements OEMSolver<VectorType>::solve().
     */
    int solveSystem(MatVecMultiplier<VectorType> *mv, VectorType *x, VectorType *b, bool reuseMatrix);
    
  private:
    /** \brief
     * These vectors are justed to calculate the final residual of the solution.
     */
    VectorType *r, *p;

    /** \brief
     * Stores the result of umfpack_di_symbolic (the symbolic analysis which is needed
     * for the numeric factorization).
     */
    void *symbolic_;

    /** \brief
     * Stores the result of umfpack_di_numeric, if multiple right hand sides will occure.
     */
    void *numeric;

    /** \brief
     * If the symbolic analysis should be done only once (for example, if the matrices
     * to solve have all the same pattern because of no adaptivity), this variable 
     * is one, otherwise 0 and the symbolic analysis will be performed at every call
     * of solveSystem().
     */
    int storeSymbolic_;

    /** \brief
     * If not zero, Umfpack is prepared to solve multiple following systems with equal
     * system matrix but different right hand side vectors.
     */
    int multipleRhs;
  };
  
}

#include "UmfPackSolver.hh"

#endif // HAVE_UMFPACK

#endif // AMDIS_UMFPACKSOLVER_H