#include "openmc/event.h"

#include "openmc/material.h"

#include "openmc/simulation.h"

#include "openmc/timer.h"

namespace openmc {

//==============================================================================

// Global variables

//==============================================================================

namespace simulation {

SharedArray<EventQueueItem> calculate_fuel_xs_queue;

SharedArray<EventQueueItem> calculate_nonfuel_xs_queue;

SharedArray<EventQueueItem> advance_particle_queue;

SharedArray<EventQueueItem> surface_crossing_queue;

SharedArray<EventQueueItem> collision_queue;

vector<Particle> particles;

} // namespace simulation

//==============================================================================

// Non-member functions

//==============================================================================

void init_event_queues(int64_t n_particles)

{

simulation::calculate_fuel_xs_queue.reserve(n_particles);

simulation::calculate_nonfuel_xs_queue.reserve(n_particles);

simulation::advance_particle_queue.reserve(n_particles);

simulation::surface_crossing_queue.reserve(n_particles);

simulation::collision_queue.reserve(n_particles);

simulation::particles.resize(n_particles);

}

void free_event_queues(void)

{

simulation::calculate_fuel_xs_queue.clear();

simulation::calculate_nonfuel_xs_queue.clear();

simulation::advance_particle_queue.clear();

simulation::surface_crossing_queue.clear();

simulation::collision_queue.clear();

simulation::particles.clear();

}

void dispatch_xs_event(int64_t buffer_idx)

{

Particle& p = simulation::particles[buffer_idx];

if (p.material() == MATERIAL_VOID ||

!model::materials[p.material()]->fissionable()) {

simulation::calculate_nonfuel_xs_queue.thread_safe_append({p, buffer_idx});

} else {

simulation::calculate_fuel_xs_queue.thread_safe_append({p, buffer_idx});

}

}

void process_init_events(int64_t n_particles, int64_t source_offset)

{

simulation::time_event_init.start();

#pragma omp parallel for schedule(runtime)

for (int64_t i = 0; i < n_particles; i++) {

initialize_history(simulation::particles[i], source_offset + i + 1);

dispatch_xs_event(i);

}

simulation::time_event_init.stop();

}

void process_calculate_xs_events(SharedArray<EventQueueItem>& queue)

{

simulation::time_event_calculate_xs.start();

// TODO: If using C++17, we could perform a parallel sort of the queue by

// particle type, material type, and then energy, in order to improve cache

// locality and reduce thread divergence on GPU. However, the parallel

// algorithms typically require linking against an additional library (Intel

// TBB). Prior to C++17, std::sort is a serial only operation, which in this

// case makes it too slow to be practical for most test problems.

//

// std::sort(std::execution::par_unseq, queue.data(), queue.data() +

// queue.size());

int64_t offset = simulation::advance_particle_queue.size();

#pragma omp parallel for schedule(runtime)

for (int64_t i = 0; i < queue.size(); i++) {

Particle* p = &simulation::particles[queue[i].idx];

p->event_calculate_xs();

// After executing a calculate_xs event, particles will

// always require an advance event. Therefore, we don't need to use

// the protected enqueuing function.

simulation::advance_particle_queue[offset + i] = queue[i];

}

simulation::advance_particle_queue.resize(offset + queue.size());

queue.resize(0);

simulation::time_event_calculate_xs.stop();

}

void process_advance_particle_events()

{

simulation::time_event_advance_particle.start();

#pragma omp parallel for schedule(runtime)

for (int64_t i = 0; i < simulation::advance_particle_queue.size(); i++) {

int64_t buffer_idx = simulation::advance_particle_queue[i].idx;

Particle& p = simulation::particles[buffer_idx];

p.event_advance();

if (!p.alive())

continue;

if (p.collision_distance() > p.boundary().distance()) {

simulation::surface_crossing_queue.thread_safe_append({p, buffer_idx});

} else {

simulation::collision_queue.thread_safe_append({p, buffer_idx});

}

}

simulation::advance_particle_queue.resize(0);

simulation::time_event_advance_particle.stop();

}

void process_surface_crossing_events()

{

simulation::time_event_surface_crossing.start();

#pragma omp parallel for schedule(runtime)

for (int64_t i = 0; i < simulation::surface_crossing_queue.size(); i++) {

int64_t buffer_idx = simulation::surface_crossing_queue[i].idx;

Particle& p = simulation::particles[buffer_idx];

p.event_cross_surface();

p.event_revive_from_secondary();

if (p.alive())

dispatch_xs_event(buffer_idx);

}

simulation::surface_crossing_queue.resize(0);

simulation::time_event_surface_crossing.stop();

}

void process_collision_events()

{

simulation::time_event_collision.start();

#pragma omp parallel for schedule(runtime)

for (int64_t i = 0; i < simulation::collision_queue.size(); i++) {

int64_t buffer_idx = simulation::collision_queue[i].idx;

Particle& p = simulation::particles[buffer_idx];

p.event_collide();

p.event_revive_from_secondary();

if (p.alive())

dispatch_xs_event(buffer_idx);

}

simulation::collision_queue.resize(0);

simulation::time_event_collision.stop();

}

void process_death_events(int64_t n_particles)

{

simulation::time_event_death.start();

#pragma omp parallel for schedule(runtime)

for (int64_t i = 0; i < n_particles; i++) {

Particle& p = simulation::particles[i];

p.event_death();

}

simulation::time_event_death.stop();

}

} // namespace openmc