opm-simulators/opm/simulators/timestepping/AdaptiveTimeStepping_impl.hpp

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#ifndef OPM_ADAPTIVETIMESTEPPING_IMPL_HEADER_INCLUDED
#define OPM_ADAPTIVETIMESTEPPING_IMPL_HEADER_INCLUDED
#include <iostream>
#include <string>
#include <utility>
#include <opm/core/simulator/AdaptiveSimulatorTimer.hpp>
#include <opm/core/simulator/PIDTimeStepControl.hpp>
namespace Opm {
// AdaptiveTimeStepping
//---------------------
AdaptiveTimeStepping::AdaptiveTimeStepping( const parameter::ParameterGroup& param )
: timeStepControl_()
, initial_fraction_( param.getDefault("solver.initialfraction", double(0.25) ) )
, restart_factor_( param.getDefault("solver.restartfactor", double(0.1) ) )
, solver_restart_max_( param.getDefault("solver.restart", int(3) ) )
, solver_verbose_( param.getDefault("solver.verbose", bool(false) ) )
, timestep_verbose_( param.getDefault("timestep.verbose", bool(false) ) )
, last_timestep_( -1.0 )
{
// valid are "pid" and "pid+iteration"
std::string control = param.getDefault("timestep.control", std::string("pid") );
const double tol = param.getDefault("timestep.control.tol", double(1e-3) );
if( control == "pid" )
timeStepControl_ = TimeStepControlType( new PIDTimeStepControl( tol ) );
else if ( control == "pid+iteration" )
{
const int iterations = param.getDefault("timestep.control.targetiteration", int(25) );
timeStepControl_ = TimeStepControlType( new PIDAndIterationCountTimeStepControl( iterations, tol ) );
}
else
OPM_THROW(std::runtime_error,"Unsupported time step control selected "<< control );
}
template <class Solver, class State, class WellState>
void AdaptiveTimeStepping::
step( Solver& solver, State& state, WellState& well_state,
const double time, const double timestep )
{
// init last time step as a fraction of the given time step
if( last_timestep_ < 0 )
last_timestep_ = initial_fraction_ * timestep ;
// create adaptive step timer with previously used sub step size
AdaptiveSimulatorTimer timer( time, time+timestep, last_timestep_ );
// copy states in case solver has to be restarted (to be revised)
State last_state( state );
WellState last_well_state( well_state );
// counter for solver restarts
int restarts = 0;
// sub step time loop
while( ! timer.done() )
{
// get current delta t
const double dt = timer.currentStepLength() ;
// initialize time step control in case current state is needed later
timeStepControl_->initialize( state );
int linearIterations = -1;
try {
// (linearIterations < 0 means on convergence in solver)
linearIterations = solver.step( dt, state, well_state);
if( solver_verbose_ ) {
// report number of linear iterations
std::cout << "Overall linear iterations used: " << linearIterations << std::endl;
}
}
catch (Opm::NumericalProblem)
{
// since linearIterations is < 0 this will restart the solver
}
// (linearIterations < 0 means on convergence in solver)
if( linearIterations >= 0 )
{
// advance by current dt
++timer;
// compute new time step estimate
const double dtEstimate =
timeStepControl_->computeTimeStepSize( dt, linearIterations, state );
if( timestep_verbose_ )
std::cout << "Suggested time step size = " << unit::convert::to(dtEstimate, unit::day) << " (days)" << std::endl;
// set new time step length
timer.provideTimeStepEstimate( dtEstimate );
// update states
last_state = state ;
last_well_state = well_state;
}
else // in case of no convergence
{
// increase restart counter
if( restarts >= solver_restart_max_ ) {
OPM_THROW(Opm::NumericalProblem,"Solver failed to converge after " << restarts << " restarts.");
}
const double newTimeStep = restart_factor_ * dt;
// we need to revise this
timer.provideTimeStepEstimate( newTimeStep );
if( solver_verbose_ )
std::cerr << "Solver convergence failed, restarting solver with new time step ("
<< unit::convert::to( newTimeStep, unit::day ) <<" days)." << std::endl;
// reset states
state = last_state;
well_state = last_well_state;
++restarts;
}
}
// store last small time step for next reportStep
last_timestep_ = timer.suggestedAverage();
if( timestep_verbose_ )
{
timer.report( std::cout );
std::cout << "Last suggested step size = " << unit::convert::to( last_timestep_, unit::day ) << " (days)" << std::endl;
}
if( ! std::isfinite( last_timestep_ ) ) // check for NaN
last_timestep_ = timestep;
}
}
#endif