gaussian-explosion.py

Go to the documentation of this file.

# This file is part of the ExaHyPE2 project. For conditions of distribution and
# use, please see the copyright notice at www.peano-framework.org
import peano4
import exahype2
 
from PDE import max_eigenvalue, flux
 
initial_conditions = """
  /**
   * With plain DG, Rusanov, and without an additional limiter, we cannot solve
   * discontinuous initial conditions. At the moment, most of the scenarios
   * are physically meaningless. The only setup that should work
   * out-of-the-box is the Gaussian, as it is infinitely smooth. Having said
   * this, the Gaussian still can run into problems if it is too steep: If the
   * polynomial order and mesh resolution are too low, the Gaussian continues
   * to look like a discontinuous initial condition and thus introduces
   * problems. Therefore, we scale its diameter with the maximum cell width. In
   * a real setup, we should also take the polynomial order into account.
   */
 
  // Manual offset to make the wave originate slightly to the left of the center
  // --- helps to detect if wave is moving to the left or right.
#if DIMENSIONS == 2
  const tarch::la::Vector<DIMENSIONS, double> circleCentre = {0.5, 0.3};
#else
  const tarch::la::Vector<DIMENSIONS, double> circleCentre = {0.18, 0.3, 0.6};
#endif
 
  const double peakDeviation = MaxAdmissibleCellH;
  const double distance = tarch::la::norm2(x - circleCentre);
  const double exponent = -(distance * distance) / 2.0 / peakDeviation / peakDeviation;
 
  Q[Shortcuts::rho] = 0.1;
  Q[Shortcuts::rhoU + 0] = 0.0;
  Q[Shortcuts::rhoU + 1] = 0.0;
#if DIMENSIONS == 3
  Q[Shortcuts::rhoU + 2] = 0.0;
#endif
  Q[Shortcuts::rhoE] = 1.0 + std::exp(exponent);
"""
 
boundary_conditions = """
  // Reflective boundary conditions
  Qoutside[Shortcuts::rho]      = Qinside[Shortcuts::rho];
  Qoutside[Shortcuts::rhoU + 0] = -Qinside[Shortcuts::rhoU + 0];
  Qoutside[Shortcuts::rhoU + 1] = -Qinside[Shortcuts::rhoU + 1];
#if DIMENSIONS == 3
  Qoutside[Shortcuts::rhoU + 2] = -Qinside[Shortcuts::rhoU + 2];
#endif
  Qoutside[Shortcuts::rhoE]     = Qinside[Shortcuts::rhoE];
"""
 
refinement_criterion = """
  auto result = ::exahype2::RefinementCommand::Keep;
 
#if DIMENSIONS == 2
  const tarch::la::Vector<DIMENSIONS, double> circleCentre = {0.5, 0.3};
#else
  const tarch::la::Vector<DIMENSIONS, double> circleCentre = {0.18, 0.3, 0.6};
#endif
 
  if (tarch::la::equals(t, 0.0)) {
    if (tarch::la::norm2(x - circleCentre) < 0.1) {
      result = ::exahype2::RefinementCommand::Refine;
    }
  }
 
  return result;
"""
 
parser = exahype2.ArgumentParser("ExaHyPE 2 - Finite Volumes Testing Script")
parser.set_defaults(
    min_depth=6,
    degrees_of_freedom=16,
)
args = parser.parse_args()
 
size = [1.0, 1.0, 1.0]
max_h = 1.1 * min(size) / (3.0**args.min_depth)
min_h = max_h * 3.0 ** (-args.amr_levels)
 
fv_solver = exahype2.solvers.fv.godunov.GlobalAdaptiveTimeStep(
    name="FVSolver",
    patch_size=args.degrees_of_freedom,
    unknowns={"rho": 1, "rhoU": args.dimensions, "rhoE": 1},
    auxiliary_variables=0,
    min_volume_h=min_h,
    max_volume_h=max_h,
    time_step_relaxation=0.5,
    use_enclave_tasking=args.enclave_tasking,
    number_of_enclave_tasks=args.ntasks,
)
 
fv_solver.set_implementation(
    initial_conditions=initial_conditions,
    boundary_conditions=boundary_conditions,
    refinement_criterion=refinement_criterion,
    max_eigenvalue=max_eigenvalue,
    flux=flux,
)
 
project = exahype2.Project(
    namespace=["tests", "exahype2", "fv"],
    project_name="GaussianExplosion",
    directory=".",
    executable="ExaHyPE",
)
project.add_solver(fv_solver)
 
if args.number_of_snapshots <= 0:
    time_in_between_plots = 0.0
else:
    time_in_between_plots = args.end_time / args.number_of_snapshots
    project.set_output_path(args.output)
 
project.set_global_simulation_parameters(
    dimensions=args.dimensions,
    size=size[0 : args.dimensions],
    offset=[0.0, 0.0, 0.0][0 : args.dimensions],
    min_end_time=args.end_time,
    max_end_time=args.end_time,
    first_plot_time_stamp=0.0,
    time_in_between_plots=time_in_between_plots,
    periodic_BC=[
        args.periodic_boundary_conditions_x,
        args.periodic_boundary_conditions_y,
        args.periodic_boundary_conditions_z,
    ],
)
 
project.set_load_balancer(
    f"new ::exahype2::LoadBalancingConfiguration({args.load_balancing_quality}, 1, {args.trees})"
)
project.set_build_mode(mode=peano4.output.string_to_mode(args.build_mode))
project = project.generate_Peano4_project(verbose=False)
project.output.makefile.set_target_device(args.target_device)
project.output.makefile.add_CXX_flag("-DGAMMA=1.4")
project.build(make=True, make_clean_first=True, throw_away_data_after_build=True)