[io] add gmsh writer class for networks

frackit/io/CMakeLists.txt

 install(FILES
 brepwriter.hh
+gmshwriter.hh
 DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/frackit/io)

frackit/io/gmshwriter.hh

+// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+// vi: set et ts=4 sw=4 sts=4:
+/*****************************************************************************
+ *   See the file COPYING for full copying permissions.                      *
+ *                                                                           *
+ *   This program is free software: you can redistribute it and/or modify    *
+ *   it under the terms of the GNU General Public License as published by    *
+ *   the Free Software Foundation, either version 2 of the License, or       *
+ *   (at your option) any later version.                                     *
+ *                                                                           *
+ *   This program 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 General Public License for more details.                            *
+ *                                                                           *
+ *   You should have received a copy of the GNU General Public License       *
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.   *
+ *****************************************************************************/
+/*!
+ * \file
+ * \brief Class that writes entity networks into Gmsh .geo file format.
+ *        Effectively, this will write a .brep file and a .geo file in
+ *        which the .brep file is included. Then, physical definitions
+ *        are added to all entity and sub-domain fragments.
+ */
+#ifndef FRACKIT_GMSH_WRITER_HH
+#define FRACKIT_GMSH_WRITER_HH
+
+#include <string>
+#include <fstream>
+
+#include "brepwriter.hh"
+
+namespace Frackit {
+
+/*!
+ * \brief Class that writes entity networks into Gmsh .geo file format.
+ *        Effectively, this will write a .brep file and a .geo file in
+ *        which the .brep file is included. Then, physical definitions
+ *        are added to all entity and sub-domain fragments.
+ */
+class GmshWriter : public BRepWriter
+{
+
+public:
+
+    /*!
+     * \brief Constructor from an entity network.
+     */
+    template<class EntityNetwork>
+    GmshWriter(const EntityNetwork& network)
+    : BRepWriter(network)
+    , entityDimension_(network.entityDimension())
+    {}
+
+    /*!
+     * \brief Write the .geo file.
+     * \param fileName The body of the file name to be used.
+     * \param meshSizeAtEntities Characteristic mesh size at entities.
+     * \param meshSizeAtBoundary Characteristic mesh size at domain boundaries.
+     * \note Two files are created: _fileName_.brep and _fileName_.geo
+     */
+    template<class ctype>
+    void write(const std::string& fileName,
+               ctype meshSizeAtEntities,
+               ctype meshSizeAtBoundary)
+    {
+        BRepWriter::write(fileName);
+
+        std::ofstream geoFile(fileName + ".geo");
+        geoFile << "Merge \"";
+        geoFile << fileName + ".brep";
+        geoFile << "\";\n";
+
+        if (!this->domainToFragmentsMap().empty())
+        {
+            geoFile << "\n// Physical domain definitions\n";
+            auto it = this->domainToFragmentsMap().begin();
+            for (; it != this->domainToFragmentsMap().end(); ++it)
+            {
+                geoFile << "Physical ";
+                if (entityDimension_ == 2) geoFile << "Volume(";
+                else if (entityDimension_ == 1) geoFile << "Surface(";
+                geoFile << it->first;
+                geoFile << ") = {";
+                geoFile << it->second[0];
+                for (unsigned int j = 1; j < it->second.size(); ++j)
+                    geoFile << ", " << it->second[j];
+                geoFile << "};\n";
+
+                // mesh size specification
+                geoFile << "Characteristic Length{ PointsOf{";
+                if (entityDimension_ == 2) geoFile << "Volume{";
+                else if (entityDimension_ == 1) geoFile << "Surface{";
+                geoFile << it->second[0];
+                for (unsigned int j = 1; j < it->second.size(); ++j)
+                    geoFile << ", " << it->second[j];
+                geoFile << "};} } = ";
+                geoFile << meshSizeAtBoundary << ";\n";
+            }
+        }
+
+        if (!this->entityToFragmentsMap().empty())
+        {
+            geoFile << "\n// Physical entity definitions\n";
+            auto it = this->entityToFragmentsMap().begin();
+            for (; it != this->entityToFragmentsMap().end(); ++it)
+            {
+                geoFile << "Physical ";
+                if (entityDimension_ == 2) geoFile << "Surface(";
+                else if (entityDimension_ == 1) geoFile << "Line(";
+                geoFile << it->first;
+                geoFile << ") = {";
+                geoFile << it->second[0];
+                for (unsigned int j = 1; j < it->second.size(); ++j)
+                    geoFile << ", " << it->second[j];
+                geoFile << "};\n";
+
+                // mesh size specification
+                geoFile << "Characteristic Length{ PointsOf{";
+                if (entityDimension_ == 2) geoFile << "Surface{";
+                else if (entityDimension_ == 1) geoFile << "Line{";
+                geoFile << it->second[0];
+                for (unsigned int j = 1; j < it->second.size(); ++j)
+                    geoFile << ", " << it->second[j];
+                geoFile << "};} } = ";
+                geoFile << meshSizeAtEntities << ";\n";
+            }
+        }
+
+        if (!this->entityIntersectionsToFragmentsMap().empty())
+        {
+            geoFile << "\n// Physical entity intersections definitions\n";
+            auto it = this->entityIntersectionsToFragmentsMap().begin();
+            for (; it != this->entityIntersectionsToFragmentsMap().end(); ++it)
+            {
+                geoFile << "Physical ";
+                if (entityDimension_ == 2) geoFile << "Line(";
+                else if (entityDimension_ == 1) geoFile << "Point(";
+                geoFile << it->first;
+                geoFile << ") = {";
+                geoFile << it->second[0];
+                for (unsigned int j = 1; j < it->second.size(); ++j)
+                    geoFile << ", " << it->second[j];
+                geoFile << "};\n";
+            }
+        }
+    }
+
+    /*!
+     * \brief Write the .geo file.
+     * \param fileName The body of the file name to be used.
+     * \param meshSizeAtEntities Characteristic mesh size at entities.
+     * \note This uses the provided mesh size on both entities and boundaries.
+     * \note Two files are created: _fileName_.brep and _fileName_.geo.
+     */
+    template<class ctype>
+    void write(const std::string& fileName, ctype meshSizeAtEntities)
+    { write(fileName, meshSizeAtEntities, meshSizeAtEntities); }
+
+private:
+    int entityDimension_;
+};
+
+} // end namespace Frackit
+
+#endif // FRACKIT_GMSH_WRITER_HH