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https://github.com/NGSolve/netgen.git
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264 lines
8.4 KiB
C++
264 lines
8.4 KiB
C++
/*! \file writegmsh2.cpp
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* \brief Export Netgen Mesh in the GMSH v2.xx File format
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* \author Philippose Rajan
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* \date 02 November 2008
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*
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* This function extends the export capabilities of
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* Netgen to include the GMSH v2.xx File Format.
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*
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* Current features of this function include:
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*
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* 1. Exports Triangles, Quadrangles and Tetrahedra \n
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* 2. Supports upto second order elements of each type
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*
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*/
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#include <mystdlib.h>
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#include <myadt.hpp>
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#include <linalg.hpp>
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#include <csg.hpp>
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#include <meshing.hpp>
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namespace netgen
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{
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#include "writeuser.hpp"
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extern MeshingParameters mparam;
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// Mapping of entities from Netgen definitions to GMSH definitions
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enum GMSH_ELEMENTS {GMSH_TRIG = 2, GMSH_TRIG6 = 9,
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GMSH_QUAD = 3, GMSH_QUAD8 = 16,
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GMSH_TET = 4, GMSH_TET10 = 11};
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const int triGmsh[7] = {0,1,2,3,6,4,5};
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const int quadGmsh[9] = {0,1,2,3,4,5,8,6,7};
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const int tetGmsh[11] = {0,1,2,3,4,5,8,6,7,10,9};
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/*! GMSH v2.xx mesh format export function
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*
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* This function extends the export capabilities of
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* Netgen to include the GMSH v2.xx File Format.
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*
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* Current features of this function include:
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*
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* 1. Exports Triangles, Quadrangles and Tetrahedra \n
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* 2. Supports upto second order elements of each type
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*
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*/
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void WriteGmsh2Format (const Mesh & mesh,
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const NetgenGeometry & geom,
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const filesystem::path & filename)
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{
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ofstream outfile (filename);
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outfile.precision(6);
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outfile.setf (ios::fixed, ios::floatfield);
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outfile.setf (ios::showpoint);
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int np = mesh.GetNP(); /// number of points in mesh
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int ne = mesh.GetNE(); /// number of 3D elements in mesh
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int nse = mesh.GetNSE(); /// number of surface elements (BC)
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int i, j, k, l;
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/*
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* 3D section : Volume elements (currently only tetrahedra)
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*/
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if ((ne > 0)
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&& (mesh.VolumeElement(1).GetNP() <= 10)
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&& (mesh.SurfaceElement(1).GetNP() <= 6))
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{
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cout << "Write GMSH v2.xx Format \n";
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cout << "The GMSH v2.xx export is currently available for elements upto 2nd Order\n" << endl;
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int inverttets = mparam.inverttets;
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int invertsurf = mparam.inverttrigs;
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/// Prepare GMSH 2.0 file (See GMSH 2.0 Documentation)
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outfile << "$MeshFormat\n";
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outfile << (float)2.0 << " "
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<< (int)0 << " "
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<< (int)sizeof(double) << "\n";
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outfile << "$EndMeshFormat\n";
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/// Write nodes
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outfile << "$Nodes\n";
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outfile << np << "\n";
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for (i = 1; i <= np; i++)
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{
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const Point3d & p = mesh.Point(i);
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outfile << i << " "; /// node number
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outfile << p.X() << " ";
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outfile << p.Y() << " ";
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outfile << p.Z() << "\n";
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}
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outfile << "$EndNodes\n";
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/// write elements (both, surface elements and volume elements)
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outfile << "$Elements\n";
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outfile << ne + nse << "\n"; //// number of elements + number of surfaces BC
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for (i = 1; i <= nse; i++)
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{
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int elType = 0;
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Element2d el = mesh.SurfaceElement(i);
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if(invertsurf) el.Invert();
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if(el.GetNP() == 3) elType = GMSH_TRIG; //// GMSH Type for a 3 node triangle
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if(el.GetNP() == 6) elType = GMSH_TRIG6; //// GMSH Type for a 6 node triangle
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if(elType == 0)
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{
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cout << " Invalid surface element type for Gmsh 2.0 3D-Mesh Export Format !\n";
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return;
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}
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outfile << i;
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outfile << " ";
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outfile << elType;
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outfile << " ";
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outfile << "2"; //// Number of tags (2 => Physical and elementary entities)
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outfile << " ";
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outfile << mesh.GetFaceDescriptor (el.GetIndex()).BCProperty() << " ";
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/// that means that physical entity = elementary entity (arbitrary approach)
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outfile << mesh.GetFaceDescriptor (el.GetIndex()).BCProperty() << " ";
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for (j = 1; j <= el.GetNP(); j++)
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{
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outfile << " ";
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outfile << el.PNum(triGmsh[j]);
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}
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outfile << "\n";
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}
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for (i = 1; i <= ne; i++)
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{
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int elType = 0;
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Element el = mesh.VolumeElement(i);
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if (inverttets) el.Invert();
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if(el.GetNP() == 4) elType = GMSH_TET; //// GMSH Element type for 4 node tetrahedron
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if(el.GetNP() == 10) elType = GMSH_TET10; //// GMSH Element type for 10 node tetrahedron
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if(elType == 0)
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{
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cout << " Invalid volume element type for Gmsh 2.0 3D-Mesh Export Format !\n";
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return;
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}
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outfile << nse + i; //// element number (Remember to add on surface elements)
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outfile << " ";
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outfile << elType;
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outfile << " ";
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outfile << "2"; //// Number of tags (2 => Physical and elementary entities)
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outfile << " ";
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outfile << 100000 + el.GetIndex();
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/// that means that physical entity = elementary entity (arbitrary approach)
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outfile << " ";
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outfile << 100000 + el.GetIndex(); /// volume number
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outfile << " ";
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for (j = 1; j <= el.GetNP(); j++)
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{
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outfile << " ";
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outfile << el.PNum(tetGmsh[j]);
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}
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outfile << "\n";
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}
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outfile << "$EndElements\n";
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}
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/*
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* End of 3D section
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*/
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/*
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* 2D section : available for triangles and quadrangles
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* upto 2nd Order
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*/
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else if(ne == 0) /// means that there's no 3D element
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{
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cout << "\n Write Gmsh v2.xx Surface Mesh (triangle and/or quadrangles upto 2nd Order)" << endl;
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/// Prepare GMSH 2.0 file (See GMSH 2.0 Documentation)
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outfile << "$MeshFormat\n";
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outfile << (float)2.0 << " "
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<< (int)0 << " "
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<< (int)sizeof(double) << "\n";
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outfile << "$EndMeshFormat\n";
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/// Write nodes
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outfile << "$Nodes\n";
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outfile << np << "\n";
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for (i = 1; i <= np; i++)
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{
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const Point3d & p = mesh.Point(i);
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outfile << i << " "; /// node number
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outfile << p.X() << " ";
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outfile << p.Y() << " ";
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outfile << p.Z() << "\n";
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}
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outfile << "$EndNodes\n";
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/// write triangles & quadrangles
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outfile << "$Elements\n";
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outfile << nse << "\n";
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for (k = 1; k <= nse; k++)
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{
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int elType = 0;
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const Element2d & el = mesh.SurfaceElement(k);
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if(el.GetNP() == 3) elType = GMSH_TRIG; //// GMSH Type for a 3 node triangle
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if(el.GetNP() == 6) elType = GMSH_TRIG6; //// GMSH Type for a 6 node triangle
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if(el.GetNP() == 4) elType = GMSH_QUAD; //// GMSH Type for a 4 node quadrangle
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if(el.GetNP() == 8) elType = GMSH_QUAD8; //// GMSH Type for an 8 node quadrangle
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if(elType == 0)
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{
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cout << " Invalid surface element type for Gmsh 2.0 2D-Mesh Export Format !\n";
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return;
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}
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outfile << k;
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outfile << " ";
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outfile << elType;
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outfile << " ";
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outfile << "2";
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outfile << " ";
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outfile << mesh.GetFaceDescriptor (el.GetIndex()).BCProperty() << " ";
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/// that means that physical entity = elementary entity (arbitrary approach)
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outfile << mesh.GetFaceDescriptor (el.GetIndex()).BCProperty() << " ";
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for (l = 1; l <= el.GetNP(); l++)
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{
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outfile << " ";
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if((elType == GMSH_TRIG) || (elType == GMSH_TRIG6))
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{
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outfile << el.PNum(triGmsh[l]);
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}
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else if((elType == GMSH_QUAD) || (elType == GMSH_QUAD8))
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{
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outfile << el.PNum(quadGmsh[l]);
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}
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}
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outfile << "\n";
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}
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outfile << "$EndElements\n";
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}
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/*
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* End of 2D section
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*/
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else
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{
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cout << " Invalid element type for Gmsh v2.xx Export Format !\n";
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}
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} // End: WriteGmsh2Format
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} // End: namespace netgen
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