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contact_detector_inline_impl.cc
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			/**
			* @file contact_detector_inline_impl.cc
			*
			* @author Mohit Pundir <mohit.pundir@epfl.ch>
			*
			* @date creation: Wed May 08 2019
			* @date last modification: Thu Jun 24 2021
			*
			* @brief inine implementation of the contact detector class
			*
			*
			* @section LICENSE
			*
			* Copyright (©) 2018-2021 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 "contact_detector.hh"
			/* -------------------------------------------------------------------------- */

			#ifndef __AKANTU_CONTACT_DETECTOR_INLINE_IMPL_CC__
			#define __AKANTU_CONTACT_DETECTOR_INLINE_IMPL_CC__

			namespace akantu {

			/* -------------------------------------------------------------------------- */
			inline bool
			ContactDetector::checkValidityOfProjection(Vector<Real> & projection) const {
			Real tolerance = 1e-3;
			return std::all_of(projection.begin(), projection.end(),
			[&tolerance](auto && xi) {
			return (xi > -1.0 - tolerance) or (xi < 1.0 + tolerance);
			});
			}

			/* -------------------------------------------------------------------------- */
			inline void ContactDetector::coordinatesOfElement(const Element & el,
			Matrix<Real> & coords) const {

			UInt nb_nodes_per_element = Mesh::getNbNodesPerElement(el.type);
			const Vector<UInt> connect = mesh.getConnectivity(el.type, _not_ghost)
			.begin(nb_nodes_per_element)[el.element];

			for (UInt n = 0; n < nb_nodes_per_element; ++n) {
			UInt node = connect[n];
			for (UInt s : arange(spatial_dimension)) {
			coords(s, n) = this->positions(node, s);
			}
			}
			}

			/* -------------------------------------------------------------------------- */
			inline void ContactDetector::computeCellSpacing(Vector<Real> & spacing) const {
			for (UInt s : arange(spatial_dimension)) {
			spacing(s) = std::sqrt(2.0) * max_dd;
			}
			}

			/* -------------------------------------------------------------------------- */
			inline void
			ContactDetector::constructGrid(SpatialGrid<UInt> & grid, BBox & bbox,
			const Array<UInt> & nodes_list) const {
			auto to_grid = [&](UInt node) {
			Vector<Real> pos(spatial_dimension);
			for (UInt s : arange(spatial_dimension)) {
			pos(s) = this->positions(node, s);
			}

			if (bbox.contains(pos)) {
			grid.insert(node, pos);
			}
			};

			std::for_each(nodes_list.begin(), nodes_list.end(), to_grid);
			}

			/* -------------------------------------------------------------------------- */
			inline void
			ContactDetector::constructBoundingBox(BBox & bbox,
			const Array<UInt> & nodes_list) const {
			auto to_bbox = [&](UInt node) {
			Vector<Real> pos(spatial_dimension);
			for (UInt s : arange(spatial_dimension)) {
			pos(s) = this->positions(node, s);
			}
			bbox += pos;
			};

			std::for_each(nodes_list.begin(), nodes_list.end(), to_bbox);

			auto & lower_bound = bbox.getLowerBounds();
			auto & upper_bound = bbox.getUpperBounds();

			lower_bound -= this->max_bb;
			upper_bound += this->max_bb;

			AKANTU_DEBUG_INFO("BBox" << bbox);
			}

			/* -------------------------------------------------------------------------- */
			inline void ContactDetector::computeMaximalDetectionDistance() {
			Real elem_size;
			Real max_elem_size = std::numeric_limits<Real>::min();
			Real min_elem_size = std::numeric_limits<Real>::max();

			auto & master_nodes = this->surface_selector->getMasterList();

			for (auto & master : master_nodes) {
			Array<Element> elements;
			this->mesh.getAssociatedElements(master, elements);

			for (auto element : elements) {
			UInt nb_nodes_per_element = mesh.getNbNodesPerElement(element.type);
			Matrix<Real> elem_coords(spatial_dimension, nb_nodes_per_element);
			this->coordinatesOfElement(element, elem_coords);

			elem_size = FEEngine::getElementInradius(elem_coords, element.type);
			max_elem_size = std::max(max_elem_size, elem_size);
			min_elem_size = std::min(min_elem_size, elem_size);
			}
			}

			AKANTU_DEBUG_INFO("The maximum element size : " << max_elem_size);

			this->min_dd = min_elem_size;
			this->max_dd = max_elem_size;
			this->max_bb = max_elem_size;
			}

			/* -------------------------------------------------------------------------- */
			inline Vector<UInt>
			ContactDetector::constructConnectivity(UInt & slave,
			const Element & master) const {
			const Vector<UInt> master_conn = this->mesh.getConnectivity(master);

			Vector<UInt> elem_conn(master_conn.size() + 1);
			elem_conn[0] = slave;
			for (UInt i = 1; i < elem_conn.size(); ++i) {
			elem_conn[i] = master_conn[i - 1];
			}

			return elem_conn;
			}

			/* -------------------------------------------------------------------------- */
			inline void
			ContactDetector::computeNormalOnElement(const Element & element,
			Vector<Real> & normal) const {
			Matrix<Real> vectors(spatial_dimension, spatial_dimension - 1);
			this->vectorsAlongElement(element, vectors);

			switch (this->spatial_dimension) {
			case 2: {
			Math::normal2(vectors.storage(), normal.storage());
			break;
			}
			case 3: {
			Math::normal3(vectors(0).storage(), vectors(1).storage(), normal.storage());
			break;
			}
			default: {
			AKANTU_ERROR("Unknown dimension : " << spatial_dimension);
			}
			}

			// to ensure that normal is always outwards from master surface
			const auto & element_to_subelement =
			mesh.getElementToSubelement(element.type)(element.element);

			Vector<Real> outside(spatial_dimension);
			mesh.getBarycenter(element, outside);

			// check if mesh facets exists for cohesive elements contact
			Vector<Real> inside(spatial_dimension);
			if (mesh.isMeshFacets()) {
			mesh.getMeshParent().getBarycenter(element_to_subelement[0], inside);
			} else {
			mesh.getBarycenter(element_to_subelement[0], inside);
			}

			Vector<Real> inside_to_outside = outside - inside;
			auto projection = inside_to_outside.dot(normal);

			if (projection < 0) {
			normal *= -1.0;
			}
			}

			/* -------------------------------------------------------------------------- */
			inline void ContactDetector::vectorsAlongElement(const Element & el,
			Matrix<Real> & vectors) const {
			auto nb_nodes_per_element = Mesh::getNbNodesPerElement(el.type);

			Matrix<Real> coords(spatial_dimension, nb_nodes_per_element);
			this->coordinatesOfElement(el, coords);

			for (auto i : arange(spatial_dimension - 1)) {
			vectors(i) = Vector<Real>(coords(i + 1)) - Vector<Real>(coords(0));
			}
			}

			/* -------------------------------------------------------------------------- */
			inline Real ContactDetector::computeGap(const Vector<Real> & slave,
			const Vector<Real> & master) const {
			auto gap = (master - slave).norm();
			return gap;
			}

			/* -------------------------------------------------------------------------- */
			inline void ContactDetector::filterBoundaryElements(
			const Array<Element> & elements, Array<Element> & boundary_elements) const {
			for (auto elem : elements) {
			const auto & element_to_subelement =
			mesh.getElementToSubelement(elem.type)(elem.element);

			// for regular boundary elements
			if (element_to_subelement.size() == 1 and
			element_to_subelement[0].kind() == _ek_regular) {
			boundary_elements.push_back(elem);
			continue;
			}

			// for cohesive boundary elements
			UInt nb_subelements_regular = 0;
			for (auto subelem : element_to_subelement) {
			if (subelem == ElementNull) {
			continue;
			}

			if (subelem.kind() == _ek_regular) {
			++nb_subelements_regular;
			}
			}

			auto nb_subelements = element_to_subelement.size();

			if (nb_subelements_regular < nb_subelements) {
			boundary_elements.push_back(elem);
			}
			}
			}

			/* -------------------------------------------------------------------------- */
			inline bool
			ContactDetector::isValidSelfContact(const UInt & slave_node, const Real & gap,
			const Vector<Real> & normal) const {
			UInt master_node;

			// finding the master node corresponding to slave node
			for (auto && pair : contact_pairs) {
			if (pair.first == slave_node) {
			master_node = pair.second;
			break;
			}
			}

			Array<Element> slave_elements;
			this->mesh.getAssociatedElements(slave_node, slave_elements);

			// Check 1 : master node is not connected to elements connected to
			// slave node
			Vector<Real> slave_normal(spatial_dimension);
			for (auto & element : slave_elements) {
			if (element.kind() != _ek_regular) {
			continue;
			}

			const Vector<UInt> connectivity = this->mesh.getConnectivity(element);

			// finding the normal at slave node by averaging of normals
			Vector<Real> normal(spatial_dimension);
			GeometryUtils::normal(mesh, positions, element, normal);
			slave_normal = slave_normal + normal;

			auto node_iter =
			std::find(connectivity.begin(), connectivity.end(), master_node);
			if (node_iter != connectivity.end()) {
			return false;
			}
			}

			// Check 2 : if gap is twice the size of smallest element
			if (std::abs(gap) > 2.0 * min_dd) {
			return false;
			}

			// Check 3 : check the directions of normal at slave node and at
			// master element, should be in opposite directions
			auto norm = slave_normal.norm();
			if (norm != 0) {
			slave_normal /= norm;
			}

			auto product = slave_normal.dot(normal);

			return not(product >= 0);
			}

			} // namespace akantu

			#endif /* __AKANTU_CONTACT_DETECTOR_INLINE_IMPL_CC__ */

rAKA/src/model/contact_mechanics/contact_detector_inline_impl.cc74f972690d3areleases/10.1007/s40571…

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rAKA/src/model/contact_mechanics/contact_detector_inline_impl.cc
74f972690d3areleases/10.1007/s40571…

contact_detector_inline_impl.cc
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