Real
CustomDT::computeDT()
{
Real new_dt;
if(_t_step==3) new_dt=getCurrentDT()*_increase_rate;
else new_dt=getCurrentDT();
return new_dt;
}
Real
RatioTimeStepper::computeDT()
{
if (_ratio > 1.0)
if(_t_step % _step == 0)
return std::min(getCurrentDT() * _ratio, _max_dt);
else
return getCurrentDT();
else
return getCurrentDT();
}
Real
TransientHalf::computeDT()
{
/**
* We won't grow timesteps with this example so if the ratio > 1.0 we'll just
* leave current_dt alone.
*/
if (_ratio < 1.0)
// Shrink our timestep by the specified ratio or return the min if it's too small
return std::max(getCurrentDT() * _ratio, _min_dt);
else
return getCurrentDT();
}
Real
SolutionTimeAdaptiveDT::computeDT()
{
//Ratio grew so switch direction
if (_sol_time_vs_dt > _old_sol_time_vs_dt && _sol_time_vs_dt > _older_sol_time_vs_dt)
{
_direction *= -1;
// Make sure we take at least two steps in this new direction
_old_sol_time_vs_dt = std::numeric_limits<Real>::max();
_older_sol_time_vs_dt = std::numeric_limits<Real>::max();
}
// if (_t_step > 1)
Real local_dt = _dt + _dt * _percent_change*_direction;
if ((_adapt_log) && (libMesh::processor_id() == 0))
{
Real out_dt = getCurrentDT();
if (out_dt > _dt_max)
out_dt = _dt_max;
_adaptive_log<<"***Time step: "<<_t_step<<", time = "<<_time+out_dt<<std::endl;
_adaptive_log<<"Cur DT: "<<out_dt<<std::endl;
_adaptive_log<<"Older Ratio: "<<_older_sol_time_vs_dt<<std::endl;
_adaptive_log<<"Old Ratio: "<<_old_sol_time_vs_dt<<std::endl;
_adaptive_log<<"New Ratio: "<<_sol_time_vs_dt<<std::endl;
}
return local_dt;
}
Real
DT2::computeDT()
{
Real curr_dt = getCurrentDT();
Real new_dt = curr_dt * std::pow(_e_tol / _error, 1.0 / _fe_problem.getNonlinearSystem().getTimeIntegrator()->order());
if (new_dt / curr_dt > _max_increase)
new_dt = curr_dt * _max_increase;
return new_dt;
}
void
DT2::step()
{
NonlinearSystem & nl = _fe_problem.getNonlinearSystem(); // returned reference is not used for anything?
TransientNonlinearImplicitSystem & nl_sys = _fe_problem.getNonlinearSystem().sys();
TransientExplicitSystem & aux_sys = _fe_problem.getAuxiliarySystem().sys();
// solve the problem with full dt
_fe_problem.solve();
_converged = nl.converged();
if (_converged)
{
// save the solution (for time step with dt)
*_u1 = *nl_sys.current_local_solution;
_u1->close();
*_aux1 = *aux_sys.current_local_solution;
_aux1->close();
// take two steps with dt/2
_console << "Taking two dt/2 time steps" << std::endl;
// restore solutions to the original state
*nl_sys.current_local_solution = *_u_saved;
*aux_sys.current_local_solution = *_aux_saved;
nl_sys.current_local_solution->close();
aux_sys.current_local_solution->close();
_dt = getCurrentDT() / 2; // cut the time step in half
_time = _time_old + _dt;
// 1. step
_fe_problem.onTimestepBegin();
// Compute Post-Aux User Objects (Timestep begin)
_fe_problem.computeUserObjects();
_console << " - 1. step" << std::endl;
Moose::setSolverDefaults(_fe_problem);
nl.solve();
_converged = nl.converged();
if (_converged)
{
nl_sys.update();
_fe_problem.computeUserObjects(EXEC_TIMESTEP_END, UserObjectWarehouse::PRE_AUX);
_fe_problem.advanceState();
_time += _dt;
// 2. step
_fe_problem.onTimestepBegin();
_fe_problem.computeUserObjects();
_console << " - 2. step" << std::endl;
Moose::setSolverDefaults(_fe_problem);
nl.solve();
_converged = nl.converged();
if (_converged)
{
nl_sys.update();
*_u2 = *nl_sys.current_local_solution;
_u2->close();
// compute error
*_u_diff = *_u2;
*_u_diff -= *_u1;
_u_diff->close();
_error = (_u_diff->l2_norm() / std::max(_u1->l2_norm(), _u2->l2_norm())) / getCurrentDT();
// restore _dt to its original value
_dt = getCurrentDT();
}
else
{
// solve failed, restore _time
_time = _time_old;
}
}
else
{
// solve failed, restore _time
_time = _time_old;
}
if (!_converged)
{
*nl_sys.current_local_solution= *_u1;
*nl_sys.old_local_solution = *_u1;
*nl_sys.older_local_solution = *_u_saved;
*aux_sys.current_local_solution = *_aux1;
*aux_sys.old_local_solution = *_aux1;
*aux_sys.older_local_solution = *_aux_saved;
nl_sys.current_local_solution->close();
nl_sys.old_local_solution->close();
nl_sys.older_local_solution->close();
aux_sys.current_local_solution->close();
aux_sys.old_local_solution->close();
aux_sys.older_local_solution->close();
}
}
}