Pre-processing
The current distribution of the code has a specific Nektar++ input format. It is formatted according to the XML standard, hence the .xml extension of the input files. The format is briefly explained in these lecture slides. Examples of input files can be found in the directories
- Nektar/library/Demos/MultiRegions/
- Nektar/solvers/AdvectionDiffusionReactionSolver/
It is possible to convert meshes generated by Gmsh to the Nektar++ input format. Therefore, we have provided a utility in the Nektar++/utilities/PreProcessing/MeshConvert directory called "MeshConvert". This routine when compiled take a .msh file (Gmsh format) as input and produces as .xml file (Nektar++ format) as output. If Nektar++ is properly compiled this can be done in the following way:
- Copy the mesh-file generated by Gmsh (call it mesh.msh) to the directory Nektar++/utilities/builds/PreProcessing/MeshConvert/
- At the terminal, go to the same directory Nektar++/utilities/builds/PreProcessing/MeshConvert/
- Convert the mesh using the MeshConvert utility by typing "./MeshConvert -g mesh.msh -o mesh.xml". This will create the file mesh.xml which can be read by Nektar++.
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Gmsh format
Gmsh is an automatic three-dimensional finite element mesh generator with built-in pre- and post-processing facilities. Its design goal is to provide a simple meshing tool for academic problems with parametric input and advanced visualization capabilities.
As it has the capability of visualising high-order data, it is particularly useful in combination with the spectral/hp element method and Nektar++.
Gmsh is distributed freely under the terms of the GNU General Public License and pre-compiled binaries for Windows, Linux and Mac OS X are available from its website.