#include "openmc/geometry.h"

#include <fmt/core.h>

#include <fmt/ostream.h>

#include "openmc/array.h"

#include "openmc/cell.h"

#include "openmc/constants.h"

#include "openmc/error.h"

#include "openmc/lattice.h"

#include "openmc/settings.h"

#include "openmc/simulation.h"

#include "openmc/string_utils.h"

#include "openmc/surface.h"

namespace openmc {

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

// Global variables

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

namespace model {

int root_universe {-1};

int n_coord_levels;

vector<int64_t> overlap_check_count;

vector<OverlapKey> overlap_keys;

std::unordered_map<OverlapKey, int, OverlapKeyHash> overlap_key_index;

} // namespace model

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

// Non-member functions

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

int check_cell_overlap(GeometryState& p, bool error)

{

int n_coord = p.n_coord();

// If no overlap found, return a nonphysical index

int overlap_index = -1;

// Loop through each coordinate level

for (int j = 0; j < n_coord; j++) {

Universe& univ = *model::universes[p.coord(j).universe()];

// Loop through each cell on this level

for (auto index_cell : univ.cells_) {

Cell& c = *model::cells[index_cell];

if (c.contains(p.coord(j).r(), p.coord(j).u(), p.surface())) {

#pragma omp atomic

++model::overlap_check_count[index_cell];

if (index_cell != p.coord(j).cell()) {

if (error) {

fatal_error(

fmt::format("Overlapping cells detected: {}, {} on universe {}",

c.id_, model::cells[p.coord(j).cell()]->id_, univ.id_));

}

// With no fatal error (plotter is calling), now adds overlaps and

// ensures order does not matter when making overlap key

int cell_a = model::cells[index_cell]->id_;

int cell_b = model::cells[p.coord(j).cell()]->id_;

int a = std::min(cell_a, cell_b);

int b = std::max(cell_a, cell_b);

OverlapKey key {univ.id_, a, b};

#pragma omp critical(overlap_key_update)

{

auto it = model::overlap_key_index.find(key);

if (it != model::overlap_key_index.end()) {

overlap_index = it->second; // already exists, reuse index

} else {

int idx = int(model::overlap_keys.size());

model::overlap_keys.push_back(key);

model::overlap_key_index[key] = idx;

overlap_index = idx;

}

}

break;

}

}

}

}

return overlap_index;

}

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

int cell_instance_at_level(const GeometryState& p, int level)

{

// throw error if the requested level is too deep for the geometry

if (level > model::n_coord_levels) {

fatal_error(fmt::format("Cell instance at level {} requested, but only {} "

"levels exist in the geometry.",

level, p.n_coord()));

}

// determine the cell instance

Cell& c {*model::cells[p.coord(level).cell()]};

// quick exit if this cell doesn't have distribcell instances

if (c.distribcell_index_ == C_NONE)

return C_NONE;

// compute the cell's instance

int instance = 0;

for (int i = 0; i < level; i++) {

const auto& c_i {*model::cells[p.coord(i).cell()]};

if (c_i.type_ == Fill::UNIVERSE) {

instance += c_i.offset_[c.distribcell_index_];

} else if (c_i.type_ == Fill::LATTICE) {

instance += c_i.offset_[c.distribcell_index_];

auto& lat {*model::lattices[p.coord(i + 1).lattice()]};

const auto& i_xyz {p.coord(i + 1).lattice_index()};

if (lat.are_valid_indices(i_xyz)) {

instance += lat.offset(c.distribcell_index_, i_xyz);

}

}

}

return instance;

}

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

bool find_cell_inner(

GeometryState& p, const NeighborList* neighbor_list, bool verbose)

{

// Find which cell of this universe the particle is in. Use the neighbor list

// to shorten the search if one was provided.

bool found = false;

int32_t i_cell = C_NONE;

if (neighbor_list) {

for (auto it = neighbor_list->cbegin(); it != neighbor_list->cend(); ++it) {

i_cell = *it;

// Make sure the search cell is in the same universe.

int i_universe = p.lowest_coord().universe();

if (model::cells[i_cell]->universe_ != i_universe)

continue;

// Check if this cell contains the particle.

Position r {p.r_local()};

Direction u {p.u_local()};

auto surf = p.surface();

if (model::cells[i_cell]->contains(r, u, surf)) {

p.lowest_coord().cell() = i_cell;

found = true;

break;

}

}

// If we're attempting a neighbor list search and fail, we

// now know we should return false. This will trigger an

// exhaustive search from neighbor_list_find_cell and make

// the result from that be appended to the neighbor list.

if (!found) {

return found;

}

}

// Check successively lower coordinate levels until finding material fill

for (;; ++p.n_coord()) {

// If we did not attempt to use neighbor lists, i_cell is still C_NONE. In

// that case, we should now do an exhaustive search to find the right value

// of i_cell.

//

// Alternatively, neighbor list searches could have succeeded, but we found

// that the fill of the neighbor cell was another universe. As such, in the

// code below this conditional, we set i_cell back to C_NONE to indicate

// that.

if (i_cell == C_NONE) {

int i_universe = p.lowest_coord().universe();

const auto& univ {model::universes[i_universe]};

found = univ->find_cell(p);

}

if (!found) {

return found;

}

i_cell = p.lowest_coord().cell();

// Announce the cell that the particle is entering.

if (found && verbose) {

auto msg = fmt::format(" Entering cell {}", model::cells[i_cell]->id_);

write_message(msg, 1);

}

Cell& c {*model::cells[i_cell]};

if (c.type_ == Fill::MATERIAL) {

// Found a material cell which means this is the lowest coord level.

p.cell_instance() = 0;

// Find the distribcell instance number.

if (c.distribcell_index_ >= 0) {

p.cell_instance() = cell_instance_at_level(p, p.n_coord() - 1);

}

// Set the material, temperature and density multiplier.

p.material_last() = p.material();

p.material() = c.material(p.cell_instance());

p.sqrtkT_last() = p.sqrtkT();

p.sqrtkT() = c.sqrtkT(p.cell_instance());

p.density_mult_last() = p.density_mult();

p.density_mult() = c.density_mult(p.cell_instance());

return true;

} else if (c.type_ == Fill::UNIVERSE) {

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

//! Found a lower universe, update this coord level then search the next.

// Set the lower coordinate level universe.

auto& coord {p.coord(p.n_coord())};

coord.universe() = c.fill_;

// Set the position and direction.

coord.r() = p.r_local();

coord.u() = p.u_local();

// Apply translation.

coord.r() -= c.translation_;

// Apply rotation.

if (!c.rotation_.empty()) {

coord.rotate(c.rotation_);

}

} else if (c.type_ == Fill::LATTICE) {

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

//! Found a lower lattice, update this coord level then search the next.

Lattice& lat {*model::lattices[c.fill_]};

// Set the position and direction.

auto& coord {p.coord(p.n_coord())};

coord.r() = p.r_local();

coord.u() = p.u_local();

// Apply translation.

coord.r() -= c.translation_;

// Apply rotation.

if (!c.rotation_.empty()) {

coord.rotate(c.rotation_);

}

// Determine lattice indices.

auto& i_xyz {coord.lattice_index()};

lat.get_indices(coord.r(), coord.u(), i_xyz);

// Get local position in appropriate lattice cell

coord.r() = lat.get_local_position(coord.r(), i_xyz);

// Set lattice indices.

coord.lattice() = c.fill_;

// Set the lower coordinate level universe.

if (lat.are_valid_indices(i_xyz)) {

coord.universe() = lat[i_xyz];

} else {

if (lat.outer_ != NO_OUTER_UNIVERSE) {

coord.universe() = lat.outer_;

} else {

p.mark_as_lost(fmt::format(

"Particle {} left lattice {}, but it has no outer definition.",

p.id(), lat.id_));

}

}

}

i_cell = C_NONE; // trip non-neighbor cell search at next iteration

found = false;

}

return found;

}

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

bool neighbor_list_find_cell(GeometryState& p, bool verbose)

{

#ifdef OPENMC_DAGMC_ENABLED

// A CSG crossing can move the particle into another instance of the same

// DAGMC universe, where the previous facet history is no longer valid.

if (p.surface() != SURFACE_NONE) {

const auto& surf = model::surfaces[p.surface_index()];

if (surf->geom_type() == GeometryType::CSG)

p.history().reset();

}

#endif

// Reset all the deeper coordinate levels.

for (int i = p.n_coord(); i < model::n_coord_levels; i++) {

p.coord(i).reset();

}

// Get the cell this particle was in previously.

auto coord_lvl = p.n_coord() - 1;

auto i_cell = p.coord(coord_lvl).cell();

Cell& c {*model::cells[i_cell]};

// Search for the particle in that cell's neighbor list. Return if we

// found the particle.

bool found = find_cell_inner(p, &c.neighbors_, verbose);

if (found)

return found;

// The particle could not be found in the neighbor list. Try searching all

// cells in this universe, and update the neighbor list if we find a new

// neighboring cell.

found = find_cell_inner(p, nullptr, verbose);

if (found)

c.neighbors_.push_back(p.coord(coord_lvl).cell());

return found;

}

void reconcile_cell_after_collision(GeometryState& p)

{

// Find the first coordinate level whose current cell is inconsistent with

// the particle's post-collision direction.

int invalid_level = C_NONE;

for (int level = 0; level < p.n_coord(); ++level) {

const auto& coord {p.coord(level)};

if (coord.cell() == C_NONE || !model::cells[coord.cell()]->contains(

coord.r(), coord.u(), SURFACE_NONE)) {

invalid_level = level;

break;

}

}

if (invalid_level == C_NONE)

return;

// Search from the first inconsistent level so that parent cells and

// transformed lower universes are both handled correctly.

if (p.coord(invalid_level).cell() != C_NONE) {

p.n_coord() = invalid_level + 1;

if (neighbor_list_find_cell(p))

return;

}

// The current cell may not have a complete neighbor list yet. Fall back to

// the normal exhaustive search used after a failed surface crossing.

p.n_coord() = 1;

if (!exhaustive_find_cell(p)) {

p.mark_as_lost("Could not find particle after a collision near a surface.");

}

}

bool exhaustive_find_cell(GeometryState& p, bool verbose)

{

int i_universe = p.lowest_coord().universe();

if (i_universe == C_NONE) {

p.coord(0).universe() = model::root_universe;

p.n_coord() = 1;

i_universe = model::root_universe;

}

// Reset all the deeper coordinate levels.

for (int i = p.n_coord(); i < model::n_coord_levels; i++) {

p.coord(i).reset();

}

return find_cell_inner(p, nullptr, verbose);

}

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

void cross_lattice(GeometryState& p, const BoundaryInfo& boundary, bool verbose)

{

auto& coord {p.lowest_coord()};

auto& lat {*model::lattices[coord.lattice()]};

if (verbose) {

write_message(

fmt::format(" Crossing lattice {}. Current position ({},{},{}). r={}",

lat.id_, coord.lattice_index()[0], coord.lattice_index()[1],

coord.lattice_index()[2], p.r()),

1);

}

// Set the lattice indices.

coord.lattice_index()[0] += boundary.lattice_translation()[0];

coord.lattice_index()[1] += boundary.lattice_translation()[1];

coord.lattice_index()[2] += boundary.lattice_translation()[2];

// Set the new coordinate position.

const auto& upper_coord {p.coord(p.n_coord() - 2)};

const auto& cell {model::cells[upper_coord.cell()]};

Position r = upper_coord.r();

r -= cell->translation_;

if (!cell->rotation_.empty()) {

r = r.rotate(cell->rotation_);

}

p.r_local() = lat.get_local_position(r, coord.lattice_index());

if (!lat.are_valid_indices(coord.lattice_index())) {

// The particle is outside the lattice. Search for it from the base coords.

p.n_coord() = 1;

bool found = exhaustive_find_cell(p);

if (!found) {

p.mark_as_lost(fmt::format("Particle {} could not be located after "

"crossing a boundary of lattice {}",

p.id(), lat.id_));

}

} else {

// Find cell in next lattice element.

p.lowest_coord().universe() = lat[coord.lattice_index()];

bool found = exhaustive_find_cell(p);

if (!found) {

// A particle crossing the corner of a lattice tile may not be found. In

// this case, search for it from the base coords.

p.n_coord() = 1;

bool found = exhaustive_find_cell(p);

if (!found) {

p.mark_as_lost(fmt::format("Particle {} could not be located after "

"crossing a boundary of lattice {}",

p.id(), lat.id_));

}

}

}

}

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

BoundaryInfo distance_to_boundary(GeometryState& p)

{

BoundaryInfo info;

double d_lat = INFINITY;

double d_surf = INFINITY;

int32_t level_surf_cross;

array<int, 3> level_lat_trans {};

// Loop over each coordinate level.

for (int i = 0; i < p.n_coord(); i++) {

const auto& coord {p.coord(i)};

const Position& r {coord.r()};

const Direction& u {coord.u()};

Cell& c {*model::cells[coord.cell()]};

// Find the oncoming surface in this cell and the distance to it.

auto surface_distance = c.distance(r, u, p.surface(), &p);

d_surf = surface_distance.first;

level_surf_cross = surface_distance.second;

// Find the distance to the next lattice tile crossing.

if (coord.lattice() != C_NONE) {

auto& lat {*model::lattices[coord.lattice()]};

// TODO: refactor so both lattice use the same position argument (which

// also means the lat.type attribute can be removed)

std::pair<double, array<int, 3>> lattice_distance;

switch (lat.type_) {

case LatticeType::rect:

lattice_distance = lat.distance(r, u, coord.lattice_index());

break;

case LatticeType::hex:

auto& cell_above {model::cells[p.coord(i - 1).cell()]};

Position r_hex {p.coord(i - 1).r()};

r_hex -= cell_above->translation_;

if (coord.rotated()) {

r_hex = r_hex.rotate(cell_above->rotation_);

}

r_hex.z = coord.r().z;

lattice_distance = lat.distance(r_hex, u, coord.lattice_index());

break;

}

d_lat = lattice_distance.first;

level_lat_trans = lattice_distance.second;

if (d_lat < 0) {

p.mark_as_lost(fmt::format("Particle {} had a negative distance "

"to a lattice boundary.",

p.id()));

}

}

// If the boundary on this coordinate level is coincident with a boundary on

// a higher level then we need to make sure that the higher level boundary

// is selected. This logic must consider floating point precision.

double& d = info.distance();

if (d_surf < d_lat - FP_COINCIDENT) {

if (d == INFINITY || (d - d_surf) / d >= FP_REL_PRECISION) {

// Update closest distance

d = d_surf;

// If the cell is not simple, it is possible that both the negative and

// positive half-space were given in the region specification. Thus, we

// have to explicitly check which half-space the particle would be

// traveling into if the surface is crossed

if (c.is_simple() || d == INFTY) {

info.surface() = level_surf_cross;

} else {

Position r_hit = r + d_surf * u;

Surface& surf {*model::surfaces[std::abs(level_surf_cross) - 1]};

Direction norm = surf.normal(r_hit);

if (u.dot(norm) > 0) {

info.surface() = std::abs(level_surf_cross);

} else {

info.surface() = -std::abs(level_surf_cross);

}

}

info.lattice_translation()[0] = 0;

info.lattice_translation()[1] = 0;

info.lattice_translation()[2] = 0;

info.coord_level() = i + 1;

}

} else {

if (d == INFINITY || (d - d_lat) / d >= FP_REL_PRECISION) {

d = d_lat;

info.surface() = SURFACE_NONE;

info.lattice_translation() = level_lat_trans;

info.coord_level() = i + 1;

}

}

}

return info;

}

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

// C API

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

extern "C" int openmc_find_cell(

const double* xyz, int32_t* index, int32_t* instance)

{

GeometryState geom_state;

geom_state.r() = Position {xyz};

geom_state.u() = {0.0, 0.0, 1.0};

if (!exhaustive_find_cell(geom_state)) {

set_errmsg(

fmt::format("Could not find cell at position {}.", geom_state.r()));

return OPENMC_E_GEOMETRY;

}

*index = geom_state.lowest_coord().cell();

*instance = geom_state.cell_instance();

return 0;

}

extern "C" int openmc_get_n_coord_levels()

{

return model::n_coord_levels;

}

extern "C" int openmc_global_bounding_box(double* llc, double* urc)

{

auto bbox = model::universes.at(model::root_universe)->bounding_box();

// set lower left corner values

llc[0] = bbox.min.x;

llc[1] = bbox.min.y;

llc[2] = bbox.min.z;

// set upper right corner values

urc[0] = bbox.max.x;

urc[1] = bbox.max.y;

urc[2] = bbox.max.z;

return 0;

}

} // namespace openmc