Fosite

Fosite is a generic framework for the numerical solution of hyperbolic conservation laws in generalized orthogonal coordinates. Its main purpose is the simulation of compressible flows in accretion disks. The underlying numerical solution method belongs to the family of unsplit conservative finite volume TVD schemes. The method is 2nd order accurate in space and uses high order Runge-Kutta schemes for time evolution. In addition to the pure advection code several source terms have been implemented to account for, e.g., shear stresses and gravitational forces.

Fosite is written in Fortran 2008 using an object-oriented design. It follows the Structure of Arrays (SoA) programming paradigm to allow for high data throughput on modern high performances architectures (SIMD). The code has been vectorized and optimized for amd64 / intel x86_64 architectures and the NEC SX-Aurora TSUBASA Vector Engine. It has been verified to compile with gfortran v8.4 and above, the current intel fortran compiler ifx v2025.0 from the intel oneAPI HPC Toolkit, AMDs flang Fortran compiler included in AOCC v5.0, NVidias nvfortran compiler included in the NVidia HPC SDK v24.11 and the LLVM flang compiler v19.

Parallelization is implemented using domain decomposition with MPI communication. It has been verified to run with MPICH, OpenMPI and NECs MPI libraries.

Additional information and help:
Website: www.astrophysik.uni-kiel.de/fosite/

Compiling the Serial Version

Fosite uses CMake to simplify the build process. In general one can enter the source directory and just type cmake and make. However, we strongly recommend out-of-place builds in order to preserve a clean source tree. Therefore one should first create a new directory, e. g. a subdirectory build within the source directory, enter that directory and then run cmake providing the path to the fosite source directory

    cmake <path_to_source>

Usually cmake searches for available Fortran compilers and takes the first compiler found. If that's not the desired compiler one can provide its command, e. g. ifx for the intel Fortran compiler, by setting the environment variable FC according to

    FC=ifx cmake <path_to_source>

In case of the LLVM Flang compilers it might also be necessary to provide the directory with the LLVM libraries and binaries, e. g.

    FC=flang cmake -DLLVM_DIR=<path_to_llvm> <path_to_source>

You can type

    cmake -L <path_to_source>

for a list of available variables and options to control the configuration process. If the configuration step finished without errors you can build fosite invoking either

    make

or

    cmake --build .

from the build directory.

Compiling the Parallel Version

In order to configure fosite for building a parallel version using MPI type

    cmake -DPARALLEL=ON <path_to_source>

If cmake fails to detect the MPI library and/or compiler or there are different MPI installations available one can provide the path to the correct MPI installation according to

    cmake -DPARALLEL=ON -DMPI_DIR=<path_to_mpi_installation> <path_to_source>

Again compilation is done by

    make

Finally run

    mpirun -n X programname

where X is the number of cores that should be used. In the standard output the partitioning can be checked at "MESH-----> MPI partitioning: X1:X2:X3" where X1X2X3 should be equal to X.

Compile on NEC-SX Aurora

On NEC-SX Aurora vector machines there is a toolchain provided. Run

    cmake -DCMAKE_TOOLCHAIN_FILE=../Toolchain-SX-Aurora.cmake <path_to_source>

Legal

The code is distributed under the GNU General Public License - see the accompanying LICENSE file for more details. So feel free to experiment with this.

Copyright (C) 2006-2025

Tobias Illenseer tillense@astrophysik.uni-kiel.de
Manuel Jung mjung@astrophysik.uni-kiel.de
Jannes Klee jklee@astrophysik.uni-kiel.de