/* -*- c++ -*- (enables emacs c++ mode) */
/*===========================================================================

 Copyright (C) 2003-2020 Yves Renard, Julien Pommier

 This file is a part of GetFEM

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/**@file gmm_MUMPS_interface.h
   @author Yves Renard <Yves.Renard@insa-lyon.fr>,
   @author Julien Pommier <Julien.Pommier@insa-toulouse.fr>
   @date December 8, 2005.
   @brief Interface with MUMPS (LU direct solver for sparse matrices).
*/
#if defined(GMM_USES_MUMPS)

#ifndef GMM_MUMPS_INTERFACE_H
#define GMM_MUMPS_INTERFACE_H

#include "gmm_kernel.h"


extern "C" {

#include <smumps_c.h>
#undef F_INT
#undef F_DOUBLE
#undef F_DOUBLE2
#include <dmumps_c.h>
#undef F_INT
#undef F_DOUBLE
#undef F_DOUBLE2
#include <cmumps_c.h>
#undef F_INT
#undef F_DOUBLE
#undef F_DOUBLE2
#include <zmumps_c.h>
#undef F_INT
#undef F_DOUBLE
#undef F_DOUBLE2

}

namespace gmm {

#define ICNTL(I) icntl[(I)-1]
#define INFO(I) info[(I)-1]
#define INFOG(I) infog[(I)-1]
#define RINFOG(I) rinfog[(I)-1]

  template <typename T> struct ij_sparse_matrix {
    std::vector<int> irn;
    std::vector<int> jcn;
    std::vector<T> a;
    bool sym;

    template <typename L> void store(const L& l, size_type i) {
       typename linalg_traits<L>::const_iterator it = vect_const_begin(l),
         ite = vect_const_end(l);
       for (; it != ite; ++it) {
         int ir = (int)i + 1, jc = (int)it.index() + 1;
         if (*it != T(0) && (!sym || ir >= jc))
         { irn.push_back(ir); jcn.push_back(jc); a.push_back(*it); }
       }
    }

    template <typename L> void build_from(const L& l, row_major) {
      for (size_type i = 0; i < mat_nrows(l); ++i)
        store(mat_const_row(l, i), i);
    }

    template <typename L> void build_from(const L& l, col_major) {
      for (size_type i = 0; i < mat_ncols(l); ++i)
        store(mat_const_col(l, i), i);
      irn.swap(jcn);
    }

    template <typename L> ij_sparse_matrix(const L& A, bool sym_) {
      size_type nz = nnz(A);
      sym = sym_;
      irn.reserve(nz); jcn.reserve(nz); a.reserve(nz);
      build_from(A,  typename principal_orientation_type<typename
                 linalg_traits<L>::sub_orientation>::potype());
    }
  };

  /* ********************************************************************* */
  /*   MUMPS solve interface                                               */
  /* ********************************************************************* */

  template <typename T> struct mumps_interf {};

  template <> struct mumps_interf<float> {
    typedef SMUMPS_STRUC_C  MUMPS_STRUC_C;
    typedef float value_type;

    static void mumps_c(MUMPS_STRUC_C &id) { smumps_c(&id); }
  };

  template <> struct mumps_interf<double> {
    typedef DMUMPS_STRUC_C  MUMPS_STRUC_C;
    typedef double value_type;
    static void mumps_c(MUMPS_STRUC_C &id) { dmumps_c(&id); }
  };

  template <> struct mumps_interf<std::complex<float> > {
    typedef CMUMPS_STRUC_C  MUMPS_STRUC_C;
    typedef mumps_complex value_type;
    static void mumps_c(MUMPS_STRUC_C &id) { cmumps_c(&id); }
  };

  template <> struct mumps_interf<std::complex<double> > {
    typedef ZMUMPS_STRUC_C  MUMPS_STRUC_C;
    typedef mumps_double_complex value_type;
    static void mumps_c(MUMPS_STRUC_C &id) { zmumps_c(&id); }
  };


  template <typename MUMPS_STRUCT>
  static inline bool mumps_error_check(MUMPS_STRUCT &id) {
    if (id.INFO(1) < 0) {
      switch (id.INFO(1)) {
        case -2:
          GMM_ASSERT1(false, "Solve with MUMPS failed: NZ = " << id.INFO(2)
                      << " is out of range");
          break;
        case -6 : case -10 :
          GMM_WARNING1("Solve with MUMPS failed: matrix is singular");
          return false;
        case -9:
          GMM_ASSERT1(false, "Solve with MUMPS failed: error "
                      << id.INFO(1) << ", increase ICNTL(14)");
          break;
        case -13 :
          GMM_ASSERT1(false, "Solve with MUMPS failed: not enough memory");
          break;
        default :
          GMM_ASSERT1(false, "Solve with MUMPS failed with error "
                      << id.INFO(1));
          break;
      }
    }
    return true;
  }


  /** MUMPS solve interface
   *  Works only with sparse or skyline matrices
   */
  template <typename MAT, typename VECTX, typename VECTB>
  bool MUMPS_solve(const MAT &A, const VECTX &X_, const VECTB &B,
                   bool sym = false, bool distributed = false) {
    VECTX &X = const_cast<VECTX &>(X_);

    typedef typename linalg_traits<MAT>::value_type T;
    typedef typename mumps_interf<T>::value_type MUMPS_T;
    GMM_ASSERT2(gmm::mat_nrows(A) == gmm::mat_ncols(A), "Non-square matrix");

    std::vector<T> rhs(gmm::vect_size(B)); gmm::copy(B, rhs);

    ij_sparse_matrix<T> AA(A, sym);

    const int JOB_INIT = -1;
    const int JOB_END = -2;
    const int USE_COMM_WORLD = -987654;

    typename mumps_interf<T>::MUMPS_STRUC_C id;

    int rank(0);
#ifdef GMM_USES_MPI
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
#endif

    id.job = JOB_INIT;
    id.par = 1;
    id.sym = sym ? 2 : 0;
    id.comm_fortran = USE_COMM_WORLD;
    mumps_interf<T>::mumps_c(id);

    if (rank == 0 || distributed) {
      id.n = int(gmm::mat_nrows(A));
      if (distributed) {
        id.nz_loc = int(AA.irn.size());
        id.irn_loc = &(AA.irn[0]);
        id.jcn_loc = &(AA.jcn[0]);
        id.a_loc = (MUMPS_T*)(&(AA.a[0]));
      } else {
        id.nz = int(AA.irn.size());
        id.irn = &(AA.irn[0]);
        id.jcn = &(AA.jcn[0]);
        id.a = (MUMPS_T*)(&(AA.a[0]));
      }
      if (rank == 0)
        id.rhs = (MUMPS_T*)(&(rhs[0]));
    }

    id.ICNTL(1) = -1; // output stream for error messages
    id.ICNTL(2) = -1; // output stream for other messages
    id.ICNTL(3) = -1; // output stream for global information
    id.ICNTL(4) = 0;  // verbosity level

    if (distributed)
      id.ICNTL(5) = 0;  // assembled input matrix (default)

    id.ICNTL(14) += 80; /* small boost to the workspace size as we have encountered some problem
                           who did not fit in the default settings of mumps..
                           by default, ICNTL(14) = 15 or 20
                        */
    //cout << "ICNTL(14): " << id.ICNTL(14) << "\n";

    if (distributed)
      id.ICNTL(18) = 3; // strategy for distributed input matrix

    // id.ICNTL(22) = 1;   /* enables out-of-core support */

    id.job = 6;
    mumps_interf<T>::mumps_c(id);
    bool ok = mumps_error_check(id);

    id.job = JOB_END;
    mumps_interf<T>::mumps_c(id);

#ifdef GMM_USES_MPI
    MPI_Bcast(&(rhs[0]),id.n,gmm::mpi_type(T()),0,MPI_COMM_WORLD);
#endif

    gmm::copy(rhs, X);

    return ok;

  }



  /** MUMPS solve interface for distributed matrices
   *  Works only with sparse or skyline matrices
   */
  template <typename MAT, typename VECTX, typename VECTB>
  bool MUMPS_distributed_matrix_solve(const MAT &A, const VECTX &X_,
                                      const VECTB &B, bool sym = false) {
    return MUMPS_solve(A, X_, B, sym, true);
  }



  template<typename T>
  inline T real_or_complex(std::complex<T> a) { return a.real(); }
  template<typename T>
  inline T real_or_complex(T &a) { return a; }


  /** Evaluate matrix determinant with MUMPS
   *  Works only with sparse or skyline matrices
   */
  template <typename MAT, typename T = typename linalg_traits<MAT>::value_type>
  T MUMPS_determinant(const MAT &A, int &exponent,
                      bool sym = false, bool distributed = false) {
    exponent = 0;
    typedef typename mumps_interf<T>::value_type MUMPS_T;
    typedef typename number_traits<T>::magnitude_type R;
    GMM_ASSERT2(gmm::mat_nrows(A) == gmm::mat_ncols(A), "Non-square matrix");

    ij_sparse_matrix<T> AA(A, sym);

    const int JOB_INIT = -1;
    const int JOB_END = -2;
    const int USE_COMM_WORLD = -987654;

    typename mumps_interf<T>::MUMPS_STRUC_C id;

    int rank(0);
#ifdef GMM_USES_MPI
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
#endif

    id.job = JOB_INIT;
    id.par = 1;
    id.sym = sym ? 2 : 0;
    id.comm_fortran = USE_COMM_WORLD;
    mumps_interf<T>::mumps_c(id);

    if (rank == 0 || distributed) {
      id.n = int(gmm::mat_nrows(A));
      if (distributed) {
        id.nz_loc = int(AA.irn.size());
        id.irn_loc = &(AA.irn[0]);
        id.jcn_loc = &(AA.jcn[0]);
        id.a_loc = (MUMPS_T*)(&(AA.a[0]));
      } else {
        id.nz = int(AA.irn.size());
        id.irn = &(AA.irn[0]);
        id.jcn = &(AA.jcn[0]);
        id.a = (MUMPS_T*)(&(AA.a[0]));
      }
    }

    id.ICNTL(1) = -1; // output stream for error messages
    id.ICNTL(2) = -1; // output stream for other messages
    id.ICNTL(3) = -1; // output stream for global information
    id.ICNTL(4) = 0;  // verbosity level

    if (distributed)
      id.ICNTL(5) = 0;  // assembled input matrix (default)

//    id.ICNTL(14) += 80; // small boost to the workspace size

    if (distributed)
      id.ICNTL(18) = 3; // strategy for distributed input matrix

    id.ICNTL(31) = 1;   // only factorization, no solution to follow
    id.ICNTL(33) = 1;   // request determinant calculation

    id.job = 4; // abalysis (job=1) + factorization (job=2)
    mumps_interf<T>::mumps_c(id);
    mumps_error_check(id);

    T det = real_or_complex(std::complex<R>(id.RINFOG(12),id.RINFOG(13)));
    exponent = id.INFOG(34);

    id.job = JOB_END;
    mumps_interf<T>::mumps_c(id);

    return det;
  }

#undef ICNTL
#undef INFO
#undef INFOG
#undef RINFOG

}


#endif // GMM_MUMPS_INTERFACE_H

#endif // GMM_USES_MUMPS
