GetDDM

GetDDM combines GetDP and Gmsh to solve large scale finite element problems using optimized Schwarz domain decomposition methods.

Examples

• Non-overlapping DDM for time-harmonic waves (Helmholtz and Maxwell)

Precompiled binaries

For demonstration purposes, download the serial pre-compiled ONELAB bundle for Windows64, Windows32, Linux64, Linux32 or MacOSX. With these precompiled binaries the examples will run in sequential mode. For parallel computations you need to recompile the codes from source with MPI support (see below).

Parallel version build

For parallel computations you need to compile GetDP and Gmsh with MPI support.

• Install MPI, CMake and Subversion.

• Download PETSc from http://www.mcs.anl.gov/petsc/petsc-as/download/. PETSc 3.4 and 3.5 have both been tested.

• Uncompress the PETSc archive (in this example, using PETSc 3.4.4):

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tar zxvf petsc-3.4.4.tar.gz

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• Configure and build PETSc. The configuration options depend on the calculations you want to perform (complex- or real-valued), as well as your compiler/MPI setup. Make sure that mpicc, mpicxx and mpif90 are in your path. Then run (remove --with-scalar-type=complex to build in real arithmetic):

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cd petsc-3.4.4 export PETSC_DIR=$PWD export PETSC_ARCH=mpi_mumps_complex ./configure --with-debugging=0 --with-clanguage=cxx --with-shared-libraries=0 --with-x=0 --download-mumps=1 --download-metis=1 --download-parmetis=1 --download-scalapack=1 --download-blacs=1 --with-scalar-type=complex make cd ..

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• Download and unzip the Gmsh and the GetDP source code from the ONELAB bundle http://onelab.info/files/gmsh-getdp-source.zip

• Configure, compile and install a minimal Gmsh library (it will be used by GetDP):

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cd gmsh-xxx mkdir lib cd lib cmake -DDEFAULT=0 -DENABLE_PARSER=1 -DENABLE_POST=1 -DENABLE_BUILD_LIB=1 .. make lib sudo make install/fast cd ../..

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• Configure and compile the MPI version of GetDP (change CC, CXX and FC depending on your MPI installation):

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cd getdp-xxx mkdir bin cd bin cmake -DENABLE_MPI=1 .. make cd ../..

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• [Optional - only for parallel mesh generation] Configure and compile the MPI version of Gmsh (need to disable Metis due to version clash with PETSc):

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cd gmsh mkdir bin cd bin cmake -DENABLE_MPI=1 -DENABLE_METIS=0 .. make

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Parallel runs

The commands for running GetDDM in parallel will depend on your particular MPI setup. Basically, the procedure would look something like this on 100 CPUs:

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mpirun -np 100 gmsh file.geo - mpirun -np 100 getdp file.pro -solve DDM

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Sample scripts for SLURM and PBS schedulers are available: [1], [2].

References

• C. Geuzaine, B. Thierry, N. Marsic, D. Colignon, A. Vion, S. Tournier, Y. Boubendir, M. El Bouajaji, and X. Antoine. An Open Source Domain Decomposition Solver for Time-Harmonic Electromagnetic Wave Problems. 2014 IEEE International Conference on Antenna Measurements & Applications. November 16-19, Antibes Juan-les-Pins, France.

• B. Thierry, A.Vion, S. Tournier, M. El Bouajaji, D. Colignon, N. Marsic, X. Antoine, C. Geuzaine. GetDDM: an Open Framework for Testing Optimized Schwarz Methods for Time-Harmonic Wave Problems. 2015.