/***************************************************************************
                               base_three.cpp
                             -------------------
                            W. Michael Brown (ORNL)

  Base class for pair styles with per-particle data for position and type

 __________________________________________________________________________
    This file is part of the LAMMPS Accelerator Library (LAMMPS_AL)
 __________________________________________________________________________

    begin                : Tue April 2, 2013
    email                : brownw@ornl.gov
 ***************************************************************************/

#include "lal_base_three.h"
using namespace LAMMPS_AL;
#define BaseThreeT BaseThree<numtyp, acctyp>

extern Device<PRECISION,ACC_PRECISION> global_device;

template <class numtyp, class acctyp>
BaseThreeT::BaseThree() : _compiled(false), _max_bytes(0)  {
  device=&global_device;
  ans=new Answer<numtyp,acctyp>();
  nbor=new Neighbor();
  #ifdef THREE_CONCURRENT
  ans2=new Answer<numtyp,acctyp>();
  #endif
}

template <class numtyp, class acctyp>
BaseThreeT::~BaseThree() {
  delete ans;
  delete nbor;
  #ifdef THREE_CONCURRENT
  delete ans2;
  #endif
}

template <class numtyp, class acctyp>
int BaseThreeT::bytes_per_atom_atomic(const int max_nbors) const {
  int b=device->atom.bytes_per_atom()+ans->bytes_per_atom()+
         nbor->bytes_per_atom(max_nbors);
  #ifdef THREE_CONCURRENT
  b+=ans2->bytes_per_atom();
  #endif
  return b;
}

template <class numtyp, class acctyp>
int BaseThreeT::init_three(const int nlocal, const int nall,
                           const int max_nbors, const int maxspecial,
                           const double cell_size, const double gpu_split,
                           FILE *_screen, const void *pair_program,
                           const char *k_two, const char *k_three_center,
                           const char *k_three_end) {
  screen=_screen;

  int gpu_nbor=0;
  if (device->gpu_mode()==Device<numtyp,acctyp>::GPU_NEIGH)
    gpu_nbor=1;
  else if (device->gpu_mode()==Device<numtyp,acctyp>::GPU_HYB_NEIGH)
    gpu_nbor=2;
  _gpu_nbor=gpu_nbor;

  int _gpu_host=0;
  int host_nlocal=hd_balancer.first_host_count(nlocal,gpu_split,gpu_nbor);
  if (host_nlocal>0)
    _gpu_host=1;

  _threads_per_atom=device->threads_per_atom();
  if (_threads_per_atom>1 && gpu_nbor==0) {
    nbor->packing(true);
    _nbor_data=&(nbor->dev_packed);
  } else
    _nbor_data=&(nbor->dev_nbor);
  if (_threads_per_atom*_threads_per_atom>device->warp_size())
    return -10;

  int success=device->init(*ans,false,false,nlocal,host_nlocal,nall,nbor,
                           maxspecial,_gpu_host,max_nbors,cell_size,false,
                           _threads_per_atom);
  if (success!=0)
    return success;

  ucl_device=device->gpu;
  atom=&device->atom;

  #ifdef THREE_CONCURRENT
  _end_command_queue=ucl_device->num_queues();
  ucl_device->push_command_queue();
  if (!ans2->init(ans->max_inum(),false,false,*(device->gpu)))
    return -3;
  ans2->cq(_end_command_queue);
  #endif

  _block_pair=device->pair_block_size();
  _block_size=device->block_ellipse();
  compile_kernels(*ucl_device,pair_program,k_two,k_three_center,k_three_end);

  // Initialize host-device load balancer
  hd_balancer.init(device,gpu_nbor,gpu_split);

  // Initialize timers for the selected GPU
  time_pair.init(*ucl_device);
  time_pair.zero();

  pos_tex.bind_float(atom->x,4);

  _max_an_bytes=ans->gpu_bytes()+nbor->gpu_bytes();
  #ifdef THREE_CONCURRENT
  _max_an_bytes+=ans2->gpu_bytes();
  #endif

  return 0;
}

template <class numtyp, class acctyp>
void BaseThreeT::estimate_gpu_overhead() {
  device->estimate_gpu_overhead(1,_gpu_overhead,_driver_overhead);
}

template <class numtyp, class acctyp>
void BaseThreeT::clear_atomic() {
  // Output any timing information
  acc_timers();
  double avg_split=hd_balancer.all_avg_split();
  _gpu_overhead*=hd_balancer.timestep();
  _driver_overhead*=hd_balancer.timestep();
  device->output_times(time_pair,*ans,*nbor,avg_split,_max_bytes+_max_an_bytes,
                       _gpu_overhead,_driver_overhead,_threads_per_atom,screen);

  if (_compiled) {
    k_three_center.clear();
    k_three_end.clear();
    k_three_end_vatom.clear();
    k_pair.clear();
    delete pair_program;
    _compiled=false;
  }

  time_pair.clear();
  hd_balancer.clear();

  nbor->clear();
  ans->clear();
  #ifdef THREE_CONCURRENT
  ans2->clear();
  assert(ucl_device->num_queues()==_end_command_queue+1);
  // ucl_device will clean up the command queue in its destructor
//  ucl_device->pop_command_queue();
  #endif
  device->clear();
}

// ---------------------------------------------------------------------------
// Copy neighbor list from host
// ---------------------------------------------------------------------------
template <class numtyp, class acctyp>
int * BaseThreeT::reset_nbors(const int nall, const int inum, const int nlist,
                              int *ilist, int *numj, int **firstneigh,
                              bool &success) {
  success=true;

  int mn=nbor->max_nbor_loop(nlist,numj,ilist);
  resize_atom(inum,nall,success);
  resize_local(nall,mn,success);
  if (!success)
    return NULL;

  // originally the requirement that nall == nlist was enforced
  // to allow direct indexing neighbors of neighbors after re-arrangement
//  nbor->get_host3(nall,nlist,ilist,numj,firstneigh,block_size());

  // now the requirement is removed, allowing to work within pair hybrid
  nbor->get_host(nlist,ilist,numj,firstneigh,block_size());

  double bytes=ans->gpu_bytes()+nbor->gpu_bytes();
  #ifdef THREE_CONCURRENT
  bytes+=ans2->gpu_bytes();
  #endif
  if (bytes>_max_an_bytes)
    _max_an_bytes=bytes;

  return ilist;
}

// ---------------------------------------------------------------------------
// Build neighbor list on device
// ---------------------------------------------------------------------------
template <class numtyp, class acctyp>
inline int BaseThreeT::build_nbor_list(const int inum, const int host_inum,
                                       const int nall, double **host_x,
                                       int *host_type, double *sublo,
                                       double *subhi, tagint *tag,
                                       int **nspecial, tagint **special,
                                       bool &success) {
  success=true;
  resize_atom(inum,nall,success);
  resize_local(nall,host_inum,nbor->max_nbors(),success);
  if (!success)
    return 0;
  atom->cast_copy_x(host_x,host_type);

  int mn;
  nbor->build_nbor_list(host_x, nall, host_inum, nall, *atom, sublo, subhi, tag,
                        nspecial, special, success, mn);

  double bytes=ans->gpu_bytes()+nbor->gpu_bytes();
  #ifdef THREE_CONCURRENT
  bytes+=ans2->gpu_bytes();
  #endif
  if (bytes>_max_an_bytes)
    _max_an_bytes=bytes;
  return mn;
}

// ---------------------------------------------------------------------------
// Copy nbor list from host if necessary and then calculate forces, virials,..
// ---------------------------------------------------------------------------
template <class numtyp, class acctyp>
void BaseThreeT::compute(const int f_ago, const int inum_full, const int nall,
                         const int nlist, double **host_x, int *host_type,
                         int *ilist, int *numj, int **firstneigh,
                         const bool eflag, const bool vflag, const bool eatom,
                         const bool vatom, int &host_start,
                         const double cpu_time, bool &success) {
  acc_timers();
  if (inum_full==0) {
    host_start=0;
    // Make sure textures are correct if realloc by a different hybrid style
    resize_atom(0,nall,success);
    zero_timers();
    return;
  }

  int ago=hd_balancer.ago_first(f_ago);
  int inum=hd_balancer.balance(ago,inum_full,cpu_time);
  ans->inum(inum);
  #ifdef THREE_CONCURRENT
  ans2->inum(inum);
  #endif
  host_start=inum;

  if (ago==0) {
    reset_nbors(nall, inum, nlist, ilist, numj, firstneigh, success);
    if (!success)
      return;
  }

  atom->cast_x_data(host_x,host_type);
  hd_balancer.start_timer();
  atom->add_x_data(host_x,host_type);

  int evatom=0;
  if (eatom || vatom)
    evatom=1;
  #ifdef THREE_CONCURRENT
  ucl_device->sync();
  #endif
  loop(eflag,vflag,evatom);
  ans->copy_answers(eflag,vflag,eatom,vatom,ilist);
  device->add_ans_object(ans);
  #ifdef THREE_CONCURRENT
  ans2->copy_answers(eflag,vflag,eatom,vatom,ilist);
  device->add_ans_object(ans2);
  #endif
  hd_balancer.stop_timer();
}

// ---------------------------------------------------------------------------
// Reneighbor on GPU if necessary and then compute forces, virials, energies
// ---------------------------------------------------------------------------
template <class numtyp, class acctyp>
int ** BaseThreeT::compute(const int ago, const int inum_full,
                                 const int nall, double **host_x, int *host_type,
                                 double *sublo, double *subhi, tagint *tag,
                                 int **nspecial, tagint **special, const bool eflag,
                                 const bool vflag, const bool eatom,
                                 const bool vatom, int &host_start,
                                 int **ilist, int **jnum,
                                 const double cpu_time, bool &success) {
  acc_timers();
  if (inum_full==0) {
    host_start=0;
    // Make sure textures are correct if realloc by a different hybrid style
    resize_atom(0,nall,success);
    zero_timers();
    return NULL;
  }

  hd_balancer.balance(cpu_time);
  int inum=hd_balancer.get_gpu_count(ago,inum_full);
  ans->inum(inum);
  #ifdef THREE_CONCURRENT
  ans2->inum(inum);
  #endif
  host_start=inum;

  // Build neighbor list on GPU if necessary
  if (ago==0) {
    build_nbor_list(inum, inum_full-inum, nall, host_x, host_type,
                    sublo, subhi, tag, nspecial, special, success);
    if (!success)
      return NULL;
    hd_balancer.start_timer();
  } else {
    atom->cast_x_data(host_x,host_type);
    hd_balancer.start_timer();
    atom->add_x_data(host_x,host_type);
  }
  *ilist=nbor->host_ilist.begin();
  *jnum=nbor->host_acc.begin();

  int evatom=0;
  if (eatom || vatom)
    evatom=1;
  #ifdef THREE_CONCURRENT
  ucl_device->sync();
  #endif
  loop(eflag,vflag,evatom);
  ans->copy_answers(eflag,vflag,eatom,vatom);
  device->add_ans_object(ans);
  #ifdef THREE_CONCURRENT
  ans2->copy_answers(eflag,vflag,eatom,vatom);
  device->add_ans_object(ans2);
  #endif
  hd_balancer.stop_timer();

  return nbor->host_jlist.begin()-host_start;
}

template <class numtyp, class acctyp>
double BaseThreeT::host_memory_usage_atomic() const {
  return device->atom.host_memory_usage()+nbor->host_memory_usage()+
         4*sizeof(numtyp)+sizeof(BaseThree<numtyp,acctyp>);
}

template <class numtyp, class acctyp>
void BaseThreeT::compile_kernels(UCL_Device &dev, const void *pair_str,
                                 const char *ktwo, const char *kthree_center,
                                 const char *kthree_end) {
  if (_compiled)
    return;

  std::string vatom_name=std::string(kthree_end)+"_vatom";

  pair_program=new UCL_Program(dev);
  pair_program->load_string(pair_str,device->compile_string().c_str());
  k_three_center.set_function(*pair_program,kthree_center);
  k_three_end.set_function(*pair_program,kthree_end);
  k_three_end_vatom.set_function(*pair_program,vatom_name.c_str());
  k_pair.set_function(*pair_program,ktwo);
  pos_tex.get_texture(*pair_program,"pos_tex");

  #ifdef THREE_CONCURRENT
  k_three_end.cq(ucl_device->cq(_end_command_queue));
  k_three_end_vatom.cq(ucl_device->cq(_end_command_queue));
  #endif

  _compiled=true;
}

template class BaseThree<PRECISION,ACC_PRECISION>;