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mesh_partition.cc
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/**
* @file mesh_partition.cc
*
* @author David Simon Kammer <david.kammer@epfl.ch>
* @author Nicolas Richart <nicolas.richart@epfl.ch>
*
* @date creation: Tue Aug 17 2010
* @date last modification: Fri Jan 22 2016
*
* @brief implementation of common part of all partitioner
*
* @section LICENSE
*
* Copyright (©) 2010-2012, 2014, 2015 EPFL (Ecole Polytechnique Fédérale de
* Lausanne) Laboratory (LSMS - Laboratoire de Simulation en Mécanique des
* Solides)
*
* Akantu is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "mesh_partition.hh"
#include "aka_iterators.hh"
#include "aka_types.hh"
#include "mesh_accessor.hh"
#include "mesh_utils.hh"
/* -------------------------------------------------------------------------- */
#include <algorithm>
#include <numeric>
#include <unordered_map>
/* -------------------------------------------------------------------------- */
namespace akantu {
/* -------------------------------------------------------------------------- */
MeshPartition::MeshPartition(const Mesh & mesh, UInt spatial_dimension,
const ID & id, const MemoryID & memory_id)
: Memory(id, memory_id), mesh(mesh), spatial_dimension(spatial_dimension),
partitions("partition", id, memory_id),
ghost_partitions("ghost_partition", id, memory_id),
ghost_partitions_offset("ghost_partition_offset", id, memory_id),
saved_connectivity("saved_connectivity", id, memory_id) {
AKANTU_DEBUG_IN();
UInt nb_total_element = 0;
for (auto && type :
mesh.elementTypes(spatial_dimension, _not_ghost, _ek_not_defined)) {
linearized_offsets.push_back(std::make_pair(type, nb_total_element));
nb_total_element += mesh.getConnectivity(type).size();
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
MeshPartition::~MeshPartition() = default;
/* -------------------------------------------------------------------------- */
UInt MeshPartition::linearized(const Element & element) {
auto it =
std::find_if(linearized_offsets.begin(), linearized_offsets.end(),
[&element](auto & a) { return a.first == element.type; });
AKANTU_DEBUG_ASSERT(it != linearized_offsets.end(),
"A bug might be crawling around this corner...");
return (it->second + element.element);
}
/* -------------------------------------------------------------------------- */
Element MeshPartition::unlinearized(UInt lin_element) {
ElementType type{_not_defined};
UInt offset{0};
for (auto & pair : linearized_offsets) {
if (lin_element < pair.second)
continue;
std::tie(type, offset) = pair;
}
return Element{type, lin_element - offset, _not_ghost};
}
/* -------------------------------------------------------------------------- */
/**
* TODO this function should most probably be rewritten in a more modern way
* conversion in c++ of the GENDUALMETIS (mesh.c) function wrote by George in
* Metis (University of Minnesota)
*/
void MeshPartition::buildDualGraph(Array<Int> & dxadj, Array<Int> & dadjncy,
Array<Int> & edge_loads,
const EdgeLoadFunctor & edge_load_func) {
AKANTU_DEBUG_IN();
std::map<ElementType, std::tuple<const Array<UInt> *, UInt, UInt>>
connectivities;
UInt spatial_dimension = mesh.getSpatialDimension();
UInt nb_total_element{0};
for (auto & type :
mesh.elementTypes(spatial_dimension, _not_ghost, _ek_not_defined)) {
auto type_p1 = mesh.getP1ElementType(type);
auto nb_nodes_per_element_p1 = mesh.getNbNodesPerElement(type_p1);
auto magic_number = mesh.getNbNodesPerElement(mesh.getFacetType(type_p1));
const auto & conn = mesh.getConnectivity(type, _not_ghost);
connectivities[type] = std::make_tuple(
&conn, nb_nodes_per_element_p1, magic_number);
nb_total_element += conn.size();
}
CSR<Element> node_to_elem;
MeshUtils::buildNode2Elements(mesh, node_to_elem);
dxadj.resize(nb_total_element + 1);
/// initialize the dxadj array
auto dxadj_it = dxadj.begin();
for (auto & pair : connectivities) {
const auto & connectivity = *std::get<0>(pair.second);
auto nb_nodes_per_element_p1 = std::get<1>(pair.second);
std::fill_n(dxadj_it, connectivity.size(), nb_nodes_per_element_p1);
dxadj_it += connectivity.size();
}
/// convert the dxadj_val array in a csr one
for (UInt i = 1; i < nb_total_element; ++i)
dxadj(i) += dxadj(i - 1);
for (UInt i = nb_total_element; i > 0; --i)
dxadj(i) = dxadj(i - 1);
dxadj(0) = 0;
dadjncy.resize(2 * dxadj(nb_total_element));
edge_loads.resize(2 * dxadj(nb_total_element));
/// weight map to determine adjacency
std::unordered_map<UInt, UInt> weight_map;
for (auto & pair : connectivities) {
auto type = pair.first;
const auto & connectivity = *std::get<0>(pair.second);
auto nb_nodes_per_element = std::get<1>(pair.second);
auto magic_number = std::get<2>(pair.second);
Element element{type, 0, _not_ghost};
for (const auto & conn :
make_view(connectivity, connectivity.getNbComponent())) {
auto linearized_el = linearized(element);
/// fill the weight map
for (UInt n : arange(nb_nodes_per_element)) {
auto && node = conn(n);
for (auto k = node_to_elem.rbegin(node); k != node_to_elem.rend(node);
--k) {
auto & current_element = *k;
auto current_el = linearized(current_element);
AKANTU_DEBUG_ASSERT(current_el != UInt(-1),
"Linearized element not found");
if (current_el <= linearized_el)
break;
auto weight_map_insert =
weight_map.insert(std::make_pair(current_el, 1));
if (not weight_map_insert.second)
(weight_map_insert.first->second)++;
}
}
/// each element with a weight of the size of a facet are adjacent
for (auto & weight_pair : weight_map) {
auto & adjacent_el = weight_pair.first;
auto magic = weight_pair.second;
if (magic != magic_number)
continue;
#if defined(AKANTU_COHESIVE_ELEMENT)
/// Patch in order to prevent neighboring cohesive elements
/// from detecting each other
auto adjacent_element = unlinearized(adjacent_el);
auto el_kind = element.kind();
auto adjacent_el_kind = adjacent_element.kind();
if (el_kind == adjacent_el_kind && el_kind == _ek_cohesive)
continue;
#endif
UInt index_adj = dxadj(adjacent_el)++;
UInt index_lin = dxadj(linearized_el)++;
dadjncy(index_lin) = adjacent_el;
dadjncy(index_adj) = linearized_el;
}
element.element++;
weight_map.clear();
}
}
Int k_start = 0, linerized_el = 0, j = 0;
for (auto & pair : connectivities) {
const auto & connectivity = *std::get<0>(pair.second);
auto nb_nodes_per_element_p1 = std::get<1>(pair.second);
auto nb_element = connectivity.size();
for (UInt el = 0; el < nb_element; ++el, ++linerized_el) {
for (Int k = k_start; k < dxadj(linerized_el); ++k, ++j)
dadjncy(j) = dadjncy(k);
dxadj(linerized_el) = j;
k_start += nb_nodes_per_element_p1;
}
}
for (UInt i = nb_total_element; i > 0; --i)
dxadj(i) = dxadj(i - 1);
dxadj(0) = 0;
UInt adj = 0;
for (UInt i = 0; i < nb_total_element; ++i) {
UInt nb_adj = dxadj(i + 1) - dxadj(i);
for (UInt j = 0; j < nb_adj; ++j, ++adj) {
Int el_adj_id = dadjncy(dxadj(i) + j);
Element el = unlinearized(i);
Element el_adj = unlinearized(el_adj_id);
Int load = edge_load_func(el, el_adj);
edge_loads(adj) = load;
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void MeshPartition::fillPartitionInformation(
const Mesh & mesh, const Int * linearized_partitions) {
AKANTU_DEBUG_IN();
CSR<Element> node_to_elem;
MeshUtils::buildNode2Elements(mesh, node_to_elem);
UInt linearized_el = 0;
for (auto & type :
mesh.elementTypes(spatial_dimension, _not_ghost, _ek_not_defined)) {
UInt nb_element = mesh.getNbElement(type);
UInt nb_nodes_per_element = Mesh::getNbNodesPerElement(type);
partitions.alloc(nb_element, 1, type, _not_ghost);
auto & ghost_part_csr = ghost_partitions_csr(type, _not_ghost);
ghost_part_csr.resizeRows(nb_element);
ghost_partitions_offset.alloc(nb_element + 1, 1, type, _ghost);
ghost_partitions.alloc(0, 1, type, _ghost);
const Array<UInt> & connectivity = mesh.getConnectivity(type, _not_ghost);
for (UInt el = 0; el < nb_element; ++el, ++linearized_el) {
UInt part = linearized_partitions[linearized_el];
partitions(type, _not_ghost)(el) = part;
std::list<UInt> list_adj_part;
for (UInt n = 0; n < nb_nodes_per_element; ++n) {
UInt node = connectivity.storage()[el * nb_nodes_per_element + n];
CSR<Element>::iterator ne;
for (ne = node_to_elem.begin(node); ne != node_to_elem.end(node);
++ne) {
const Element & adj_element = *ne;
UInt adj_el = linearized(adj_element);
UInt adj_part = linearized_partitions[adj_el];
if (part != adj_part) {
list_adj_part.push_back(adj_part);
}
}
}
list_adj_part.sort();
list_adj_part.unique();
for (auto & adj_part : list_adj_part) {
ghost_part_csr.getRows().push_back(adj_part);
ghost_part_csr.rowOffset(el)++;
ghost_partitions(type, _ghost).push_back(adj_part);
ghost_partitions_offset(type, _ghost)(el)++;
}
}
ghost_part_csr.countToCSR();
/// convert the ghost_partitions_offset array in an offset array
Array<UInt> & ghost_partitions_offset_ptr =
ghost_partitions_offset(type, _ghost);
for (UInt i = 1; i < nb_element; ++i)
ghost_partitions_offset_ptr(i) += ghost_partitions_offset_ptr(i - 1);
for (UInt i = nb_element; i > 0; --i)
ghost_partitions_offset_ptr(i) = ghost_partitions_offset_ptr(i - 1);
ghost_partitions_offset_ptr(0) = 0;
}
// All Facets
for (Int sp = spatial_dimension - 1; sp >= 0; --sp) {
for (auto & type : mesh.elementTypes(sp, _not_ghost, _ek_not_defined)) {
UInt nb_element = mesh.getNbElement(type);
partitions.alloc(nb_element, 1, type, _not_ghost);
AKANTU_DEBUG_INFO("Allocating partitions for " << type);
auto & ghost_part_csr = ghost_partitions_csr(type, _not_ghost);
ghost_part_csr.resizeRows(nb_element);
ghost_partitions_offset.alloc(nb_element + 1, 1, type, _ghost);
ghost_partitions.alloc(0, 1, type, _ghost);
AKANTU_DEBUG_INFO("Allocating ghost_partitions for " << type);
const Array<std::vector<Element>> & elem_to_subelem =
mesh.getElementToSubelement(type, _not_ghost);
for (UInt i(0); i < mesh.getNbElement(type, _not_ghost);
++i) { // Facet loop
const std::vector<Element> & adjacent_elems = elem_to_subelem(i);
if (!adjacent_elems.empty()) {
Element min_elem{_max_element_type, std::numeric_limits<UInt>::max(),
*ghost_type_t::end()};
UInt min_part(std::numeric_limits<UInt>::max());
std::set<UInt> adjacent_parts;
for (UInt j(0); j < adjacent_elems.size(); ++j) {
UInt adjacent_elem_id = adjacent_elems[j].element;
UInt adjacent_elem_part =
partitions(adjacent_elems[j].type,
adjacent_elems[j].ghost_type)(adjacent_elem_id);
if (adjacent_elem_part < min_part) {
min_part = adjacent_elem_part;
min_elem = adjacent_elems[j];
}
adjacent_parts.insert(adjacent_elem_part);
}
partitions(type, _not_ghost)(i) = min_part;
auto git = ghost_partitions_csr(min_elem.type, _not_ghost)
.begin(min_elem.element);
auto gend = ghost_partitions_csr(min_elem.type, _not_ghost)
.end(min_elem.element);
for (; git != gend; ++git) {
adjacent_parts.insert(min_part);
}
adjacent_parts.erase(min_part);
for (auto & part : adjacent_parts) {
ghost_part_csr.getRows().push_back(part);
ghost_part_csr.rowOffset(i)++;
ghost_partitions(type, _ghost).push_back(part);
}
ghost_partitions_offset(type, _ghost)(i + 1) =
ghost_partitions_offset(type, _ghost)(i + 1) +
adjacent_elems.size();
} else {
partitions(type, _not_ghost)(i) = 0;
}
}
ghost_part_csr.countToCSR();
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void MeshPartition::tweakConnectivity(const Array<UInt> & pairs) {
AKANTU_DEBUG_IN();
if (pairs.size() == 0)
return;
Mesh::type_iterator it =
mesh.firstType(spatial_dimension, _not_ghost, _ek_not_defined);
Mesh::type_iterator end =
mesh.lastType(spatial_dimension, _not_ghost, _ek_not_defined);
for (; it != end; ++it) {
ElementType type = *it;
Array<UInt> & conn =
const_cast<Array<UInt> &>(mesh.getConnectivity(type, _not_ghost));
UInt nb_nodes_per_element = conn.getNbComponent();
UInt nb_element = conn.size();
Array<UInt> & saved_conn = saved_connectivity.alloc(
nb_element, nb_nodes_per_element, type, _not_ghost);
saved_conn.copy(conn);
for (UInt i = 0; i < pairs.size(); ++i) {
for (UInt el = 0; el < nb_element; ++el) {
for (UInt n = 0; n < nb_nodes_per_element; ++n) {
if (pairs(i, 1) == conn(el, n))
conn(el, n) = pairs(i, 0);
}
}
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
void MeshPartition::restoreConnectivity() {
AKANTU_DEBUG_IN();
MeshAccessor mesh_accessor(const_cast<Mesh &>(mesh));
for (auto && type : saved_connectivity.elementTypes(
spatial_dimension, _not_ghost, _ek_not_defined)) {
auto & conn = mesh_accessor.getConnectivity(type, _not_ghost);
auto & saved_conn = saved_connectivity(type, _not_ghost);
conn.copy(saved_conn);
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
bool MeshPartition::hasPartitions(const ElementType & type,
const GhostType & ghost_type) {
return partitions.exists(type, ghost_type);
}
/* -------------------------------------------------------------------------- */
} // namespace akantu

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