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contact_manager.hh
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/**
* @file contact_manager.hh
*
* @author Alejandro M. Aragón <alejandro.aragon@epfl.ch>
*
* @date creation: Fri Jan 04 2013
* @date last modification: Sun Oct 19 2014
*
* @brief contact manager
*
* @section LICENSE
*
* Copyright (©) 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/>.
*
*/
/* -------------------------------------------------------------------------- */
#ifndef __AKANTU_CMANAGER_HH__
#define __AKANTU_CMANAGER_HH__
#include "aka_common.hh"
#include "surface.hh"
#include "zone.hh"
#include "element.hh"
__BEGIN_AKANTU__
template <int d>
class BBox_sorter {
typedef CSurface<d> surface_type;
struct Comparator {
template <class surface_pointer>
bool operator()(surface_pointer s1, surface_pointer s2) const {
typedef typename surface_type::bbox_type bbox_type;
auto b1 = s1->bounding_box();
auto b2 = s2->bounding_box();
// consider min point for sorting (chosen arbitrarily)
return b1.min(d-1) < b2.min(d-1);
// NOTE: point coordinates are 0-based, so calling d-1 with
// dimension 2 actually gets the second element of the
// coordinate array
}
};
public:
template <class pointer>
static std::pair<pointer, pointer> check(pointer p1, pointer p2) {
typedef std::pair<pointer, pointer> contact_pair;
return p1 < p2 ? contact_pair(p1,p2) : contact_pair(p2,p1);
}
template <class surface_container, class intersection_container>
static void sort(surface_container& surfaces, intersection_container& intersections) {
typedef typename surface_container::value_type surface_ptr;
typedef typename surface_type::bbox_type bbox_type;
typedef typename surface_container::iterator surface_iterator;
typedef typename intersection_container::value_type contact_pair;
// sort container
surfaces.sort(Comparator());
// loop over sorted surfaces
surface_iterator it1 = surfaces.begin();
surface_iterator it2 = ++surfaces.begin();
for (; it2 != surfaces.end(); ++it2) {
// check for intersection of bounding boxes
auto b1 = (*it1)->bounding_box();
auto b2 = (*it2)->bounding_box();
// if bounding boxes intersect
if (b1 & b2) {
// add pair to set
intersections.insert(check(*it1,*it2));
++it1;
} else {
// remove pair from set
intersections.erase(check(*it1,*it2));
// remove first surface from container, as it does not
// intersect other surfaces
surfaces.erase(it1++);
}
}
if (surfaces.size() > 1)
BBox_sorter<d-1>::sort(surfaces, intersections);
}
};
//! Partial template specialization for zero dimension
/*! This class finishes the recursion on dimension by doing nothing in the
* sort function.
*/
template <>
struct BBox_sorter<0> {
template <class surface_container, class intersection_container>
static void sort(surface_container&, intersection_container&) {}
};
template <int d>
class CManager {
typedef SolidMechanicsModel model_type;
typedef CSurface<d> contact_surface;
typedef std::vector<contact_surface> surface_container;
typedef typename surface_container::iterator surface_iterator;
typedef typename surface_container::const_iterator const_surface_iterator;
typedef CZone<d> contact_zone;
typedef std::list<contact_zone*> zone_container;
typedef typename zone_container::iterator zone_iterator;
typedef typename zone_container::const_iterator const_zone_iterator;
typedef CElement<d> contact_element;
typedef std::list<contact_element> celement_container;
typedef typename celement_container::const_iterator celement_iterator;
SolidMechanicsModel &model_;
surface_container surfaces_;
zone_container zones_;
celement_container celements_;
Contact_type c_;
public:
void clear() {
zones_.clear();
celements_.clear();
}
CManager(model_type& model, Contact_type c = No_self_contact_t) : model_(model), c_(c) {
// get mesh from model
Mesh &mesh = model.getMesh();
// call update current position to be able to call later
// the function to get current positions
model.updateCurrentPosition();
// obtain exterior surfaces
MeshUtils::buildFacets(mesh);
// assign surface ids
MeshUtils::buildSurfaceID(mesh);
// allocate memory for surfaces
UInt nb_surfaces = mesh.getNbSurfaces();
surfaces_.reserve(nb_surfaces);
for (UInt i=0; i<nb_surfaces; ++i)
surfaces_.push_back(contact_surface(model));
// iterate over elements of lower dimension
Mesh::type_iterator it = mesh.firstType(d-1);
Mesh::type_iterator end = mesh.lastType(d-1);
for(; it != end; ++it) {
UInt nb_element = mesh.getNbElement(*it);
UInt nb_nodes = mesh.getNbNodesPerElement(*it);
const Array<UInt> &conn = mesh.getConnectivity(*it);
Array<UInt> &surf_id = mesh.getSurfaceID(*it);
// add elements to corresponding surface
for(UInt e = 0; e < nb_element; ++e) {
CSurface<d> &surface = surfaces_.at(surf_id(e));
surface.add_element(*it,e);
// add element nodes to surface
for (UInt n = 0; n<nb_nodes; ++n)
surface.add_node(conn(e, n));
}
}
}
~CManager() {
// delete over contact zones
for (zone_iterator it = zones_.begin(); it != zones_.end(); ++it)
delete *it;
}
void global_search() {
#ifdef DEBUG_CONTACT
cout<<"__________________________________________________________"<<endl;
cout<<"*** INFO *** Printing contact manager after global search."<<endl;
#endif
typedef const contact_surface* surface_ptr;
typedef std::list<surface_ptr> surface_list;
typedef std::pair<surface_ptr, surface_ptr> contact_pair;
typedef std::set<contact_pair> intersection_container;
typedef typename intersection_container::iterator intersection_iterator;
typedef typename contact_surface::bbox_type bbox_type;
// create container of bounding boxes used for the sort and
// the container to store intersections
surface_list list;
intersection_container intersections;
// loop over surfaces to update bounding boxes
for (surface_iterator it = surfaces_.begin(); it != surfaces_.end(); ++it) {
const contact_surface &surface = *it;
it->update_bounding_box();
list.push_back(&surface);
}
// carry out sort in all dimensions to check for intersections
BBox_sorter<d>::sort(list, intersections);
if (!intersections.empty()) {
// loop over intersections to find contact zones
for (intersection_iterator it = intersections.begin();
it != intersections.end(); ++it) {
// get contact surfaces that intersect
const contact_surface &surface1 = *it->first;
const contact_surface &surface2 = *it->second;
// find intersection bounding box
bbox_type bb = surface1.bounding_box() && surface2.bounding_box();
// find elements that intersect with the above bounding box
std::set<const Element*> intersected_elements;
surface1.intersects(bb, intersected_elements);
#if DEBUG_CONTACT
UInt inter = intersected_elements.size();
cout<<"Surface 1 contains "<<inter<<" elements in contact zone."<<endl;
#endif
surface2.intersects(bb, intersected_elements);
#if DEBUG_CONTACT
cout<<"Surface 2 contains "<<(intersected_elements.size() - inter)<<" elements in contact zone."<<endl;
#endif
// if intersected_elements container is not empty, a contact zone can be created
if (!intersected_elements.empty()) {
// now that the intersection has been found, get contact
// zone object using bounding box and intersecting elements
zones_.push_back(new contact_zone(model_, bb,intersected_elements, surface1, surface2));
}
}
}
#ifdef DEBUG_CONTACT
cout<<*this;
#endif
}
void local_search() {
typedef typename contact_zone::node_set node_set;
typedef typename contact_zone::node_iterator node_iterator;
typedef typename contact_zone::element_container element_set;
typedef typename contact_zone::element_iterator element_iterator;
// loop over contact zones
for (zone_iterator it = zones_.begin(); it != zones_.end(); ++it) {
contact_zone& cs = **it;
// loop over buckets in current contact zone
// incrementation of the iterator is done when removing the bucket taking
// care of not invalidating the iterators
for (typename contact_zone::bucket_iterator bit = cs.buckets_begin(); bit != cs.buckets_end();) {
// get nodes of bucket plus those of contiguous buckets
element_set contiguous = cs.contiguous(bit->first);
const Element* closest = NULL;
// flagged nodes in case that a node belongs to several buckets
// (node in bucket boundaries)
node_set flaggedNodes;
// loop over nodes
for (node_iterator nit1 = bit->second.begin(); nit1 != bit->second.end(); ++nit1) {
auto np = *nit1;
// node has already been considered for a contact element,
// do nothing further with it
node_iterator fit = flaggedNodes.find(np);
if (fit != flaggedNodes.end())
continue;
Real m = std::numeric_limits<Real>::infinity();
// loop over elements
for (element_iterator sit = contiguous.begin(); sit != contiguous.end(); ++sit) {
// checkf if no self-contact is allowed
if (c_ == No_self_contact_t)
if (cs.in_surface(np, *sit)) {
#ifdef DEBUG_CONTACT
cout<<"*** INFO *** Node "<<np<<" and element "<<(*sit)->element<<" belong to the same surface"<<endl;
#endif
continue;
}
// check if node pointed by np lies in the same segment
if (cs.in_element(np, *sit)) {
#ifdef DEBUG_CONTACT
cout<<"*** INFO *** Node "<<np<<" belongs to element "<<*sit<<endl;
#endif
continue;
}
// compute distance from node to element using SQP
Real length = distance<d>(np, *sit, model_);
if (length < m) {
m = length;
closest = *sit;
}
} // loop over elements
// if a close node was found that does not belong to the
// same element, add contact element for resolution
if (closest) {
celements_.push_back(contact_element(np, closest, model_));
flaggedNodes.insert(np);
}
#ifdef DEBUG_CONTACT
else
cout<<"*** INFO *** No close element was found for node "<<np<<endl;
#endif
} // loop over nodes in bucket
// remove bucket for further search as it is not needed
cs.erase_bucket(bit++);
} // loop over buckests
#ifdef DEBUG_CONTACT
// print contact elements
print_celements(cout);
#endif
} // loop over contact zones
}
void remove_penetrations() {
// loop over contact elements
for (celement_iterator eit = celements_.begin(); eit != celements_.end(); ++eit) {
bool flag = eit->penetrates();
if (flag) {
#ifdef DEBUG_CONTACT
cout<<"*** WARNING *** Penetration occurs for element "<<*eit<<endl;
#endif
cout<<"*** INFO *** Collision detected, aborting..."<<endl;
exit(1);
// eit->remove_penetration();
}
}
// clear non-permanent objects
clear();
}
void print_celements(std::ostream& os) {
os<<" Contact elements: "<<celements_.size()<<endl;
for (celement_iterator eit = celements_.begin(); eit != celements_.end(); ++eit)
os<<*eit;
}
//! Enable std output
friend std::ostream& operator<<(std::ostream& os, const CManager& cm) {
os<<"Contact manager info: "<<endl;
os<<" Contact surfaces: "<<cm.surfaces_.size()<<endl;
typename CManager::const_surface_iterator it = cm.surfaces_.begin();
for (; it != cm.surfaces_.end(); ++it)
os<<*it;
os<<" Contact zones: "<<cm.zones_.size()<<endl;
for (typename CManager::const_zone_iterator it = cm.zones_.begin(); it != cm.zones_.end(); ++it)
os<<**it;
return os;
}
};
__END_AKANTU__
#endif /* __AKANTU_CMANAGER_HH__ */

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