MHD_GDDC_GPU

MHD_GDDC_GPU is a GPU accelerated code based on the TENO and Gradient Descent Divergence Cleaning method ( GDDC ) to solve the ideal magnetohydrodynamics equations.

Compiling

MHD_GDDC_GPU requires the NVFORTRAN compiler ( download from: https://developer.nvidia.com/hpc-sdk-downloads ). The compilation script has been prepared (./source/make_mhd), and the compilation command is:

sh make_mhd

Running

MHD_GDDC_GPU can only run on hardware equipped with NVIDIA GPUs. In addition one file has to be specified:

• input.dat: A file that defines the physical and numerical setup of the simulation, which can be customized based on specific requirements. Examples of input.dat files can be found in the cases folder.

Thus, to run a simulation, type, e.g.:

./MHD_GDDC_GPU.out ./input.dat

Interpreting the input.dat file

casename defines the case name

xmin defines the x-min boundary of the domain

xmax defines the x-max boundary of the domain

ymin defines the y-min boundary of the domain

ymax defines the y-max boundary of the domain

dt defines the time step

End time defines the total simulation time

NTF defines the output interval of results

eta defines the parameter $\eta$ of GDDC

gamma defines the parameter $\gamma$

bxmin defines the type of x-min boundary ( inlet -> inlet, out -> outflow, cyc -> cyclic, sym -> symmetry )

bxmax defines the type of x-max boundary ( inlet -> inlet, out -> outflow, cyc -> cyclic, sym -> symmetry )

bymin defines the type of y-min boundary ( inlet -> inlet, out -> outflow, cyc -> cyclic, sym -> symmetry )

bymax defines the type of y-max boundary ( inlet -> inlet, out -> outflow, cyc -> cyclic, sym -> symmetry )

Inlet origin variables: rho, u, v, w, p, Bx, By, Bz define the inlet boundary primitive variables

restart defines whether to restart a simulation ( 0 -> without restart, 1 -> restart )

Interpreting the outputs

Once the calculation is started, a folder will be created in the current directory with the name format "case name+time". As the calculation progresses, MHD_GDDC_GPU will output three types of files in the folder: Info.dat, restart.*.dat, and TEC.*.dat.

• Info.dat: the file contains basic configuration information for the simulation.

• restart.*.dat: files are used to restart the simulation

• TEC.*.dat: result files that can be imported into Tecplot to post-processed.

Contributing

We welcome any contributions and feedback that can help improve MHD_GDDC_GPU. If you would like to contribute to the tool, please contact the maintainers or open an Issue in the repository or a thread in Discussions. Pull Requests are encouraged, but please propose or discuss the changes in the associated Issue beforehand.

Licencing

Please refer to the licence file.