Introduction

t8dg (spoken as "tet-de-ge") is a C/C++ software to use a discontinuous galerkin method on adaptive meshes. t8dg uses t8code as a mesh managing library. It is licensed under the GNU General Public License 3.0 or later. Copyright (c) 2020 the developers.

Setup

We provide a short guide to install t8dg.

For a more detailed description, please see the Installation guide.

Requirements

• libsc (Included in t8dg's git repository)
• p4est (Included in t8dg's git repository)
• t8code (Included in t8dg's git repository)
• automake
• libtool
• make

Steps

To setup the project perform the following steps

1.) If you cloned from github, initialize and download the git submodules
   t8code, p4est and sc.
  - git submodule init
  - git submodule update      
2.) Call the bootstrap script in the source directory
  - ./bootstrap        
3.) Goto your installation folder and call configure and make
  - cd /path/to/install
  - /path/to/source/configure [OPTIONS]
  - make 
  - make check
  - make install

To see a list of possible configure options, call

./configure -h

Most commonly used for t8dg are

--enable-mpi (enables MPI parallelization)

--enable-debug (enables debugging mode - massively reduces performance)

Example configurations

For a parallel release mode with local installation path $HOME/t8dg_install:

configure --enable-mpi CFLAGS=-O3 CXXFLAGS=-O3 --prefix=$HOME/t8dg_install

For a debugging mode with static linkage (makes using gdb and valgrind more comfortable):

configure --enable-mpi --enable-debug --enable-static --disable-shared CFLAGS="-Wall -O0 -g" CXXFLAGS="-Wall -O0 -g"

Getting started

  1. configure and make as above
  2. Go to exec folder
    - cd /path/to/install
    - cd exec
  3. Call t8dg with -h flag to show possible options 
    - ./t8dg -h
  4. Call t8dg with appropriate options, for example with 
    - minimum refinement level 3, maximum refinement level 5 (-l3 -r5)
    - spatial and time integration order 4 (-L4 -o4)
    - CFL number = 0.05 (-C0.05) (can be chosen higher for smaller integration order)
    - square mesh (-m3)
    - and circular step function as initial condition (-i6):
    - ./t8dg -l3 -r5 -L4 -o4 -C0.05 -m3 -i6
  5. If t8dg is configured with MPI, call it with mpirun to execute in parallel:
    - mpirun -n 4 ./t8dg -l3 -r5 -L4 -o4 -C0.05 -m3 -i6
  6. t8dg produces the vtu files 't8dg_advection_*.{p}vtu'.
     To investigate, you can open the pvtu files in paraview.
     We suggest coloring for 'Num. Solution' and enabling 'Surface with edges'.

Publications

An (incomplete) list of publications related to t8dg:

[1] Lukas Dreyer, The local discontinuous galerkin method for the advection-diffusion equation on adaptive meshes, Master thesis at University of Bonn, 2021, Full text available

Citing t8dg

If you use t8dg in any of your publications, please cite the github repository and [1].