1 // Copyright (C) 2007-2008 CEA/DEN, EDF R&D
3 // This library is free software; you can redistribute it and/or
4 // modify it under the terms of the GNU Lesser General Public
5 // License as published by the Free Software Foundation; either
6 // version 2.1 of the License.
8 // This library is distributed in the hope that it will be useful,
9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 // Lesser General Public License for more details.
13 // You should have received a copy of the GNU Lesser General Public
14 // License along with this library; if not, write to the Free Software
15 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 // See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
20 #include "CommInterface.hxx"
21 #include "Topology.hxx"
22 #include "BlockTopology.hxx"
23 #include "ComponentTopology.hxx"
24 #include "ParaFIELD.hxx"
25 #include "MPIProcessorGroup.hxx"
26 #include "ParaMESH.hxx"
28 #include "InterpolationMatrix.hxx"
29 #include "IntersectionDEC.hxx"
30 #include "ElementLocator.hxx"
38 \defgroup intersectiondec IntersectionDEC
40 \section overview Overview
42 The IntersectionDEC enables the \ref conservativeremapping of fields between two parallel codes. This remapping is based on the computation of intersection volumes between elements from code A and elements from code B. The computation is possible for 3D meshes, 2D meshes, and 3D-surface meshes. Dimensions must be similar for code A and code B (for instance, though it could be desirable, it is not yet possible to couple 3D surfaces with 2D surfaces).
44 In the present version, only fields lying on elements are considered.
46 \image html NonCoincident_small.png "Example showing the transfer from a field based on a quadrangular mesh to a triangular mesh. In a P0-P0 interpolation, to obtain the value on a triangle, the values on quadrangles are weighted by their intersection area and summed."
48 \image latex NonCoincident_small.eps "Example showing the transfer from a field based on a quadrangular mesh to a triangular mesh. In a P0-P0 interpolation, to obtain the value on a triangle, the values on quadrangles are weighted by their intersection area and summed."
50 A typical use of IntersectionDEC encompasses two distinct phases :
51 - A setup phase during which the intersection volumes are computed and the communication structures are setup. This corresponds to calling the IntersectionDEC::synchronize() method.
52 - A use phase during which the remappings are actually performed. This corresponds to the calls to sendData() and recvData() which actually trigger the data exchange. The data exchange are synchronous in the current version of the library so that recvData() and sendData() calls must be synchronized on code A and code B processor groups.
54 The following code excerpt illutrates a typical use of the IntersectionDEC class.
58 IntersectionDEC dec(groupA, groupB);
59 dec.attachLocalField(field);
61 if (groupA.containsMyRank())
63 else if (groupB.containsMyRank())
67 A \ref conservativeremapping of the field from the source mesh to the target mesh is performed by the function synchronise(), which computes the \ref remappingmatrix.
69 Computing the field on the receiving side can be expressed in terms of a matrix-vector product : \f$ \phi_t=W.\phi_s\f$, with \f$ \phi_t \f$ the field on the target side and \f$ \phi_s \f$ the field on the source side.
70 When remapping a 3D surface to another 3D surface, a projection phase is necessary to match elements from both sides. Care must be taken when defining this projection to obtain a \ref conservative remapping.
72 In the P0-P0 case, this matrix is a plain rectangular matrix with coefficients equal to the intersection areas between triangle and quadrangles. For instance, in the above figure, the matrix is :
75 \begin{tabular}{|cccc|}
77 0.46 & 0 & 0.51 & 0.03\\
78 0.42 & 0.53 & 0 & 0.05\\
79 0 & 0 & 0.92 & 0.05 \\
85 \section intersectiondec_options Options
86 On top of \ref dec_options, options supported by %IntersectionDEC objects are
87 related to the underlying Intersector class.
88 All the options available in the intersector objects are
89 available for the %IntersectionDEC object. The various options available for * intersectors can be reviewed in \ref InterpKerIntersectors.
93 IntersectionDEC dec(source_group, target_group);
94 dec.attachLocalField(field);
95 dec.setOptions("DoRotate",false);
96 dec.setOptions("Precision",1e-12);
100 \warning{ Options must be set before calling the synchronize method. }
104 \addtogroup intersectiondec
108 IntersectionDEC::IntersectionDEC()
113 This constructor creates an IntersectionDEC which has \a source_group as a working side
114 and \a target_group as an idle side. All the processors will actually participate, but intersection computations will be performed on the working side during the \a synchronize() phase.
115 The constructor must be called synchronously on all processors of both processor groups.
117 \param source_group working side ProcessorGroup
118 \param target_group lazy side ProcessorGroup
121 IntersectionDEC::IntersectionDEC(ProcessorGroup& source_group, ProcessorGroup& target_group):
122 DEC(source_group, target_group),_interpolation_matrix(0)
127 IntersectionDEC::~IntersectionDEC()
129 if (_interpolation_matrix !=0)
130 delete _interpolation_matrix;
134 \brief Synchronization process for exchanging topologies.
136 This method prepares all the structures necessary for sending data from a processor group to the other. It uses the mesh underlying the fields that have been set with attachLocalField method.
137 It works in four steps :
138 -# Bounding boxes are computed for each subdomain,
139 -# The lazy side mesh parts that are likely to intersect the working side local processor are sent to the working side,
140 -# The working side calls the interpolation kernel to compute the intersection between local and imported mesh.
141 -# The lazy side is updated so that it knows the structure of the data that will be sent by
142 the working side during a \a sendData() call.
145 void IntersectionDEC::synchronize()
147 ParaMEDMEM::ParaMESH* para_mesh = _local_field->getSupport();
148 //cout <<"size of Interpolation Matrix"<<sizeof(InterpolationMatrix)<<endl;
149 _interpolation_matrix = new InterpolationMatrix (para_mesh, *_source_group,*_target_group,*this,*this);
151 //setting up the communication DEC on both sides
152 if (_source_group->containsMyRank())
154 //locate the distant meshes
155 ElementLocator locator(*para_mesh, *_target_group);
157 //transfering option from IntersectionDEC to ElementLocator
158 locator.setBoundingBoxAdjustment(getBoundingBoxAdjustment());
160 MEDCouplingUMesh* distant_mesh=0;
162 for (int i=0; i<_target_group->size(); i++)
164 // int idistant_proc = (i+_source_group->myRank())%_target_group->size();
167 //gathers pieces of the target meshes that can intersect the local mesh
168 locator.exchangeMesh(idistant_proc,distant_mesh,distant_ids);
169 std::string distantMeth;
170 locator.exchangeMethod(_method,idistant_proc,distantMeth);
171 if (distant_mesh !=0)
173 //adds the contribution of the distant mesh on the local one
174 int idistant_proc_in_union=_union_group->translateRank(_target_group,idistant_proc);
175 std::cout <<"add contribution from proc "<<idistant_proc_in_union<<" to proc "<<_union_group->myRank()<<std::endl;
176 _interpolation_matrix->addContribution(*distant_mesh,idistant_proc_in_union,distant_ids,_method,distantMeth);
178 distant_mesh->decrRef();
179 delete[] distant_ids;
186 if (_target_group->containsMyRank())
188 ElementLocator locator(*para_mesh, *_source_group);
189 //transfering option from IntersectionDEC to ElementLocator
190 locator.setBoundingBoxAdjustment(getBoundingBoxAdjustment());
192 MEDCouplingUMesh* distant_mesh=0;
194 for (int i=0; i<_source_group->size(); i++)
196 // int idistant_proc = (i+_target_group->myRank())%_source_group->size();
198 //gathers pieces of the target meshes that can intersect the local mesh
199 locator.exchangeMesh(idistant_proc,distant_mesh,distant_ids);
200 std::cout << " Data sent from "<<_union_group->myRank()<<" to source proc "<< idistant_proc<<std::endl;
201 std::string distantMeth;
202 locator.exchangeMethod(_method,idistant_proc,distantMeth);
205 distant_mesh->decrRef();
206 delete[] distant_ids;
212 _interpolation_matrix->prepare();
217 Receives the data whether the processor is on the working side or on the lazy side. It must match a \a sendData() call on the other side.
219 void IntersectionDEC::recvData()
221 if (_source_group->containsMyRank())
222 _interpolation_matrix->transposeMultiply(*_local_field->getField());
223 else if (_target_group->containsMyRank())
225 _interpolation_matrix->multiply(*_local_field->getField());
226 if (getForcedRenormalization())
227 renormalizeTargetField();
233 Receives the data at time \a time in asynchronous mode. The value of the field
234 will be time-interpolated from the field values received.
235 \param time time at which the value is desired
237 void IntersectionDEC::recvData( double time )
239 _interpolation_matrix->getAccessDEC()->setTime(time);
244 Sends the data whether the processor is on the working side or on the lazy side.
245 It must match a recvData() call on the other side.
247 void IntersectionDEC::sendData()
249 if (_source_group->containsMyRank())
252 _interpolation_matrix->multiply(*_local_field->getField());
253 if (getForcedRenormalization())
254 renormalizeTargetField();
257 else if (_target_group->containsMyRank())
258 _interpolation_matrix->transposeMultiply(*_local_field->getField());
262 Sends the data available at time \a time in asynchronous mode.
263 \param time time at which the value is available
264 \param deltatime time interval between the value presently sent and the next one.
266 void IntersectionDEC::sendData( double time , double deltatime )
268 _interpolation_matrix->getAccessDEC()->setTime(time,deltatime);