GlobalTimeStepping.cpph

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#include "peano4/parallel/SpacetreeSet.h"
 
 
template <typename Particle>
void swift2::timestepping::
  computeAdmissibleTimeStepSizeFromGlobalMeshSizeAndMaximumVelocity(
    const double cflFactor,
    const double initialTimeStepSize,
    double       maxRelativeGrowth
  ) {
  const double minH = peano4::parallel::SpacetreeSet::getInstance()
                        .getGridStatistics()
                        .getMinH()(0);
  const double maxV = Particle::getSpecies().getMaxVelocity();
 
  if (tarch::la::equals(maxV, 0.0)) {
    Particle::getSpecies().setTimeStepSize(initialTimeStepSize);
  } else {
    double oldTimeStepSize = Particle::getSpecies().getMaxTimeStepSize();
    double newTimeStepSize = std::min(
      cflFactor * minH / maxV,
      oldTimeStepSize * (1.0 + maxRelativeGrowth)
    );
    Particle::getSpecies().setTimeStepSize(newTimeStepSize, false);
  }
}
 
 
template <typename Particle>
void swift2::timestepping::computeCFLTimeStepSizeSPH() {
 
  assert(false);
  // Don't use this.
  // TODO mladen: delete this once other timestepping is done.
 
  const double initialTimeStepSize = Particle::getInitialTimeStepSize();
  const bool   adjustTimeStepSize  = Particle::getAdjustTimeStepSize();
 
  /* Set initial time step size */
  Particle::getSpecies().setTimeStepSize(initialTimeStepSize);
 
  if (adjustTimeStepSize) {
    // @TODO implement the CFL time step for SPH. IT depends not on V but on the
    // signal velocity.
    assertionMsg(false, "adjustable time step size not implemented yet");
  }
}