// Copyright (C) 2011, Science and Technology Facilities Council.
// Copyright (C) 2009, Jonathan Hogg <jdh41.at.cantab.net>.
// Copyright (C) 2004, 2007 International Business Machines and others.
// All Rights Reserved.
// This code is published under the Eclipse Public License.
//
// Authors: Jonathan Hogg                    STFC   2011-03-15
//          Jonathan Hogg                           2009-07-29
//          Carl Laird, Andreas Waechter     IBM    2004-03-17

#include "IpoptConfig.h"
#include "IpMa86SolverInterface.hpp"

#include <cmath>

#ifdef IPOPT_HAS_HSL
#include "CoinHslConfig.h"
#endif

namespace Ipopt
{

static IPOPT_DECL_MA86_DEFAULT_CONTROL(*user_ma86_default_control) = NULL;
static IPOPT_DECL_MA86_ANALYSE(*user_ma86_analyse) = NULL;
static IPOPT_DECL_MA86_FACTOR(*user_ma86_factor) = NULL;
static IPOPT_DECL_MA86_FACTOR_SOLVE(*user_ma86_factor_solve) = NULL;
static IPOPT_DECL_MA86_SOLVE(*user_ma86_solve) = NULL;
static IPOPT_DECL_MA86_FINALISE(*user_ma86_finalise) = NULL;
static IPOPT_DECL_MC68_DEFAULT_CONTROL(*user_mc68_default_control) = NULL;
static IPOPT_DECL_MC68_ORDER(*user_mc68_order) = NULL;

Ma86SolverInterface::~Ma86SolverInterface()
{
   delete[] val_;
   delete[] order_;

   if( keep_ )
   {
      ma86_finalise(&keep_, &control_);
   }
}

void Ma86SolverInterface::RegisterOptions(
   SmartPtr<RegisteredOptions> roptions
)
{
   roptions->AddIntegerOption(
      "ma86_print_level",
      "Debug printing level",
      -1,
      "<0: no printing; 0: Error and warning messages only; 1: Limited diagnostic printing; >1 Additional diagnostic printing.");
   roptions->AddLowerBoundedIntegerOption(
      "ma86_nemin",
      "Node Amalgamation parameter",
      1,
      32,
      "Two nodes in elimination tree are merged if result has fewer than ma86_nemin variables.");
   roptions->AddLowerBoundedNumberOption(
      "ma86_small",
      "Zero Pivot Threshold",
      0.0, false,
      1e-20,
      "Any pivot less than ma86_small is treated as zero.");
   roptions->AddLowerBoundedNumberOption(
      "ma86_static",
      "Static Pivoting Threshold",
      0.0, false,
      0.0,
      "See MA86 documentation. "
      "Either ma86_static=0.0 or ma86_static>ma86_small. "
      "ma86_static=0.0 disables static pivoting.");
   roptions->AddBoundedNumberOption(
      "ma86_u",
      "Pivoting Threshold",
      0.0, false,
      0.5, false,
      1e-8,
      "See MA86 documentation.");
   roptions->AddBoundedNumberOption(
      "ma86_umax",
      "Maximum Pivoting Threshold",
      0.0, false,
      0.5, false,
      1e-4,
      "Maximum value to which u will be increased to improve quality.");
   roptions->AddStringOption3(
      "ma86_scaling",
      "Controls scaling of matrix",
      "mc64",
      "none", "Do not scale the linear system matrix",
      "mc64", "Scale linear system matrix using MC64",
      "mc77", "Scale linear system matrix using MC77 [1,3,0]");
   roptions->AddStringOption3(
      "ma86_order",
      "Controls type of ordering",
#ifdef COINHSL_HAS_METIS
      "auto",
#else
      "amd",
#endif
      "auto", "Try both AMD and MeTiS, pick best",
      "amd", "Use the HSL_MC68 approximate minimum degree algorithm",
      "metis", "Use the MeTiS nested dissection algorithm (if available)");
}

void Ma86SolverInterface::SetFunctions(
   IPOPT_DECL_MA86_DEFAULT_CONTROL(*ma86_default_control),
   IPOPT_DECL_MA86_ANALYSE(*ma86_analyse),
   IPOPT_DECL_MA86_FACTOR(*ma86_factor),
   IPOPT_DECL_MA86_FACTOR_SOLVE(*ma86_factor_solve),
   IPOPT_DECL_MA86_SOLVE(*ma86_solve),
   IPOPT_DECL_MA86_FINALISE(*ma86_finalise),
   IPOPT_DECL_MC68_DEFAULT_CONTROL(*mc68_default_control),
   IPOPT_DECL_MC68_ORDER(*mc68_order)
)
{
   DBG_ASSERT(ma86_default_control != NULL);
   DBG_ASSERT(ma86_analyse != NULL);
   DBG_ASSERT(ma86_factor != NULL);
   DBG_ASSERT(ma86_factor_solve != NULL);
   DBG_ASSERT(ma86_solve != NULL);
   DBG_ASSERT(ma86_finalise != NULL);
   DBG_ASSERT(mc68_default_control != NULL);
   DBG_ASSERT(mc68_order != NULL);

   user_ma86_default_control = ma86_default_control;
   user_ma86_analyse = ma86_analyse;
   user_ma86_factor = ma86_factor;
   user_ma86_factor_solve = ma86_factor_solve;
   user_ma86_solve = ma86_solve;
   user_ma86_finalise = ma86_finalise;
   user_mc68_default_control = mc68_default_control;
   user_mc68_order = mc68_order;
}

bool Ma86SolverInterface::InitializeImpl(
   const OptionsList& options,
   const std::string& prefix
)
{
   if( user_ma86_default_control != NULL )
   {
      ma86_default_control = user_ma86_default_control;
      ma86_analyse = user_ma86_analyse;
      ma86_factor = user_ma86_factor;
      ma86_factor_solve = user_ma86_factor_solve;
      ma86_solve = user_ma86_solve;
      ma86_finalise = user_ma86_finalise;
      mc68_default_control = user_mc68_default_control;
      mc68_order = user_mc68_order;
   }
   else
   {
#if (defined(COINHSL_HAS_MA86) && !defined(IPOPT_SINGLE)) || (defined(COINHSL_HAS_MA86S) && defined(IPOPT_SINGLE))
      // use HSL functions that should be available in linked HSL library
      ma86_default_control = &::ma86_default_control;
      ma86_analyse = &::ma86_analyse;
      ma86_factor = &::ma86_factor;
      ma86_factor_solve = &::ma86_factor_solve;
      ma86_solve = &::ma86_solve;
      ma86_finalise = &::ma86_finalise;
      mc68_default_control = &::mc68_default_control;
      mc68_order = &::mc68_order;
#else
      // try to load HSL functions from a shared library at runtime
      DBG_ASSERT(IsValid(hslloader));

#define STR2(x) #x
#define STR(x) STR2(x)
      ma86_default_control = (IPOPT_DECL_MA86_DEFAULT_CONTROL(*))hslloader->loadSymbol(STR(ma86_default_control));
      ma86_analyse = (IPOPT_DECL_MA86_ANALYSE(*))hslloader->loadSymbol(STR(ma86_analyse));
      ma86_factor = (IPOPT_DECL_MA86_FACTOR(*))hslloader->loadSymbol(STR(ma86_factor));
      ma86_factor_solve = (IPOPT_DECL_MA86_FACTOR_SOLVE(*))hslloader->loadSymbol(STR(ma86_factor_solve));
      ma86_solve = (IPOPT_DECL_MA86_SOLVE(*))hslloader->loadSymbol(STR(ma86_solve));
      ma86_finalise = (IPOPT_DECL_MA86_FINALISE(*))hslloader->loadSymbol(STR(ma86_finalise));
      mc68_default_control = (IPOPT_DECL_MC68_DEFAULT_CONTROL(*))hslloader->loadSymbol(STR(mc68_default_control));
      mc68_order = (IPOPT_DECL_MC68_ORDER(*))hslloader->loadSymbol(STR(mc68_order));
#endif
   }

   DBG_ASSERT(ma86_default_control != NULL);
   DBG_ASSERT(ma86_analyse != NULL);
   DBG_ASSERT(ma86_factor != NULL);
   DBG_ASSERT(ma86_factor_solve != NULL);
   DBG_ASSERT(ma86_solve != NULL);
   DBG_ASSERT(ma86_finalise != NULL);
   DBG_ASSERT(mc68_default_control != NULL);
   DBG_ASSERT(mc68_order != NULL);

   ma86_default_control(&control_);
   control_.f_arrays = 1; // Use Fortran numbering (faster)
   /* Note: we can't set control_.action = false as we need to know the
    * intertia. (Otherwise we just enter the restoration phase and fail) */

   Index temp;
   options.GetIntegerValue("ma86_print_level", temp, prefix);
   control_.diagnostics_level = temp;
   options.GetIntegerValue("ma86_nemin", temp, prefix);
   control_.nemin = temp;
   options.GetNumericValue("ma86_small", control_.small_, prefix);
   options.GetNumericValue("ma86_static", control_.static_, prefix);
   options.GetNumericValue("ma86_u", control_.u, prefix);
   options.GetNumericValue("ma86_umax", umax_, prefix);
   std::string order_method, scaling_method;
   options.GetStringValue("ma86_order", order_method, prefix);
   if( order_method == "metis" )
   {
      ordering_ = ORDER_METIS;
   }
   else if( order_method == "amd" )
   {
      ordering_ = ORDER_AMD;
   }
   else
   {
      ordering_ = ORDER_AUTO;
   }
   options.GetStringValue("ma86_scaling", scaling_method, prefix);
   if( scaling_method == "mc64" )
   {
      control_.scaling = 1;
   }
   else if( scaling_method == "mc77" )
   {
      control_.scaling = 2;
   }
   else
   {
      control_.scaling = 0;
   }

   return true; // All is well
}

ESymSolverStatus Ma86SolverInterface::InitializeStructure(
   Index        dim,
   Index        nonzeros,
   const Index* ia,
   const Index* ja
)
{
   struct ma86_info info, info2;
   struct mc68_control control68;
   struct mc68_info info68;
   int* order_amd;
   int* order_metis;
   void* keep_amd;
   void* keep_metis;

   // Store size for later use
   ndim_ = dim;

   if( HaveIpData() )
   {
      IpData().TimingStats().LinearSystemSymbolicFactorization().Start();
   }

   // Determine an ordering
   mc68_default_control(&control68);
   control68.f_array_in = 1; // Use Fortran numbering (faster)
   control68.f_array_out = 1; // Use Fortran numbering (faster)
   order_amd = NULL;
   order_metis = NULL;
   DBG_ASSERT(ordering_ == ORDER_METIS || ordering_ == ORDER_AMD || ordering_ == ORDER_AUTO);
   if( ordering_ == ORDER_METIS || ordering_ == ORDER_AUTO )
   {
      order_metis = new int[dim];
      mc68_order(3, dim, ia, ja, order_metis, &control68, &info68); /* MeTiS */
      if( info68.flag == -5 )
      {
         // MeTiS not available
         ordering_ = ORDER_AMD;
         delete[] order_metis;
         order_metis = NULL;
      }
      else if( info68.flag < 0 )
      {
         return SYMSOLVER_FATAL_ERROR;
      }
   }
   if( ordering_ == ORDER_AMD || ordering_ == ORDER_AUTO )
   {
      order_amd = new int[dim];
      mc68_order(1, dim, ia, ja, order_amd, &control68, &info68); /* AMD */
   }
   if( info68.flag < 0 )
   {
      return SYMSOLVER_FATAL_ERROR;
   }

   // perform analyse
   if( ordering_ == ORDER_AUTO )
   {
      ma86_analyse(dim, ia, ja, order_amd, &keep_amd, &control_, &info2);
      if( info2.flag < 0 )
      {
         return SYMSOLVER_FATAL_ERROR;
      }
      ma86_analyse(dim, ia, ja, order_metis, &keep_metis, &control_, &info);
      if( info.flag < 0 )
      {
         return SYMSOLVER_FATAL_ERROR;
      }
      if( info.num_flops > info2.num_flops )
      {
         // Use AMD
         order_ = order_amd;
         keep_ = keep_amd;
         delete[] order_metis;
         ma86_finalise(&keep_metis, &control_);
      }
      else
      {
         // Use MeTiS
         order_ = order_metis;
         keep_ = keep_metis;
         delete[] order_amd;
         ma86_finalise(&keep_amd, &control_);
      }
   }
   else
   {
      if( ordering_ == ORDER_AMD )
      {
         order_ = order_amd;
      }
      if( ordering_ == ORDER_METIS )
      {
         order_ = order_metis;
      }
      ma86_analyse(dim, ia, ja, order_, &keep_, &control_, &info);
   }

   if( HaveIpData() )
   {
      IpData().TimingStats().LinearSystemSymbolicFactorization().End();
   }

   // Setup memory for values
   if( val_ != NULL )
   {
      delete[] val_;
   }
   val_ = new Number[nonzeros];

   if( info.flag >= 0 )
   {
      return SYMSOLVER_SUCCESS;
   }
   else
   {
      return SYMSOLVER_FATAL_ERROR;
   }
}

ESymSolverStatus Ma86SolverInterface::MultiSolve(
   bool         new_matrix,
   const Index* ia,
   const Index* ja,
   Index        nrhs,
   Number*      rhs_vals,
   bool         check_NegEVals,
   Index        numberOfNegEVals)
{
   struct ma86_info info;

   if( new_matrix || pivtol_changed_ )
   {

      if( HaveIpData() )
      {
         IpData().TimingStats().LinearSystemFactorization().Start();
      }
      //ma86_factor(ndim_, ia, ja, val_, order_, &keep_, &control_, &info);
      ma86_factor_solve(ndim_, ia, ja, val_, order_, &keep_, &control_, &info, nrhs, ndim_, rhs_vals, NULL);
      if( HaveIpData() )
      {
         IpData().TimingStats().LinearSystemFactorization().End();
      }
      if( info.flag < 0 )
      {
         return SYMSOLVER_FATAL_ERROR;
      }
      if( info.flag == 2 /* || info.flag == -3 */ )
      {
         return SYMSOLVER_SINGULAR;
      }
      if( check_NegEVals && info.num_neg != numberOfNegEVals )
      {
         return SYMSOLVER_WRONG_INERTIA;
      }

      /*if (HaveIpData()) {
       IpData().TimingStats().LinearSystemBackSolve().Start();
       }
       ma86_solve(0, 1, ndim_, rhs_vals, order_, &keep_, &control_, &info);
       if (HaveIpData()) {
       IpData().TimingStats().LinearSystemBackSolve().End();
       }*/

      numneg_ = info.num_neg;
      pivtol_changed_ = false;
   }
   else
   {
      if( HaveIpData() )
      {
         IpData().TimingStats().LinearSystemBackSolve().Start();
      }
      ma86_solve(0, nrhs, ndim_, rhs_vals, order_, &keep_, &control_, &info,
                 NULL);
      if( HaveIpData() )
      {
         IpData().TimingStats().LinearSystemBackSolve().End();
      }
   }

   return SYMSOLVER_SUCCESS;
}

bool Ma86SolverInterface::IncreaseQuality()
{
   if( control_.u >= umax_ )
   {
      return false;
   }

   pivtol_changed_ = true;

   Jnlst().Printf(J_DETAILED, J_LINEAR_ALGEBRA,
                  "Increasing pivot tolerance for HSL_MA86 from %7.2e ", control_.u);
   control_.u = Min(umax_, std::pow(control_.u, Number(0.75)));
   Jnlst().Printf(J_DETAILED, J_LINEAR_ALGEBRA,
                  "to %7.2e.\n", control_.u);
   return true;
}

} // namespace Ipopt
