SimulatorReport AdaptiveTimeStepping::
stepImpl( const SimulatorTimer& simulatorTimer,
Solver& solver, State& state, WState& well_state,
Output* outputWriter )
{
SimulatorReport report;
const double timestep = simulatorTimer.currentStepLength();
// init last time step as a fraction of the given time step
if( suggested_next_timestep_ < 0 ) {
suggested_next_timestep_ = restart_factor_ * timestep;
}
if (full_timestep_initially_) {
suggested_next_timestep_ = timestep;
}
// TODO
// take change in well state into account
// create adaptive step timer with previously used sub step size
AdaptiveSimulatorTimer substepTimer( simulatorTimer, suggested_next_timestep_, max_time_step_ );
// copy states in case solver has to be restarted (to be revised)
State last_state( state );
WState last_well_state( well_state );
// counter for solver restarts
int restarts = 0;
// sub step time loop
while( ! substepTimer.done() )
{
// get current delta t
const double dt = substepTimer.currentStepLength() ;
if( timestep_verbose_ )
{
std::ostringstream ss;
ss <<" Substep " << substepTimer.currentStepNum() << ", stepsize "
<< unit::convert::to(substepTimer.currentStepLength(), unit::day) << " days.";
OpmLog::info(ss.str());
}
SimulatorReport substepReport;
try {
substepReport = solver.step( substepTimer, state, well_state);
report += substepReport;
if( solver_verbose_ ) {
// report number of linear iterations
OpmLog::note("Overall linear iterations used: " + std::to_string(substepReport.total_linear_iterations));
}
}
catch (const Opm::NumericalProblem& e) {
detail::logException(e, solver_verbose_);
// since linearIterations is < 0 this will restart the solver
}
catch (const std::runtime_error& e) {
detail::logException(e, solver_verbose_);
// also catch linear solver not converged
}
catch (const Dune::ISTLError& e) {
detail::logException(e, solver_verbose_);
// also catch errors in ISTL AMG that occur when time step is too large
}
catch (const Dune::MatrixBlockError& e) {
detail::logException(e, solver_verbose_);
// this can be thrown by ISTL's ILU0 in block mode, yet is not an ISTLError
}
if( substepReport.converged )
{
// advance by current dt
++substepTimer;
// create object to compute the time error, simply forwards the call to the model
detail::SolutionTimeErrorSolverWrapper< Solver, State >
relativeChange( solver, last_state, state );
// compute new time step estimate
double dtEstimate =
timeStepControl_->computeTimeStepSize( dt, substepReport.total_linear_iterations, relativeChange, substepTimer.simulationTimeElapsed());
// limit the growth of the timestep size by the growth factor
dtEstimate = std::min( dtEstimate, double(max_growth_ * dt) );
// further restrict time step size growth after convergence problems
if( restarts > 0 ) {
dtEstimate = std::min( growth_factor_ * dt, dtEstimate );
// solver converged, reset restarts counter
restarts = 0;
}
if( timestep_verbose_ )
{
std::ostringstream ss;
ss << " Substep summary: ";
if (report.total_well_iterations != 0) {
ss << "well iterations = " << report.total_well_iterations << ", ";
}
ss << "newton iterations = " << report.total_newton_iterations << ", "
<< "linearizations = " << report.total_linearizations
<< " (" << report.assemble_time << " sec), "
<< "linear iterations = " << report.total_linear_iterations
<< " (" << report.linear_solve_time << " sec)";
OpmLog::info(ss.str());
}
// write data if outputWriter was provided
// if the time step is done we do not need
// to write it as this will be done by the simulator
// anyway.
if( outputWriter && !substepTimer.done() ) {
Opm::time::StopWatch perfTimer;
perfTimer.start();
bool substep = true;
const auto& physicalModel = solver.model();
outputWriter->writeTimeStep( substepTimer, state, well_state, physicalModel, substep);
report.output_write_time += perfTimer.secsSinceStart();
}
// set new time step length
substepTimer.provideTimeStepEstimate( dtEstimate );
// update states
last_state = state ;
last_well_state = well_state;
report.converged = substepTimer.done();
}
else // in case of no convergence (linearIterations < 0)
{
report.converged = false;
// increase restart counter
if( restarts >= solver_restart_max_ ) {
const auto msg = std::string("Solver failed to converge after ")
+ std::to_string(restarts) + " restarts.";
if (solver_verbose_) {
OpmLog::error(msg);
}
OPM_THROW_NOLOG(Opm::NumericalProblem, msg);
}
const double newTimeStep = restart_factor_ * dt;
// we need to revise this
substepTimer.provideTimeStepEstimate( newTimeStep );
if( solver_verbose_ ) {
std::string msg;
msg = "Solver convergence failed, restarting solver with new time step ("
+ std::to_string(unit::convert::to( newTimeStep, unit::day )) + " days).\n";
OpmLog::problem(msg);
}
// reset states
state = last_state;
well_state = last_well_state;
++restarts;
}
}
// store estimated time step for next reportStep
suggested_next_timestep_ = substepTimer.currentStepLength();
if( timestep_verbose_ )
{
std::ostringstream ss;
substepTimer.report(ss);
ss << "Suggested next step size = " << unit::convert::to( suggested_next_timestep_, unit::day ) << " (days)" << std::endl;
OpmLog::note(ss.str());
}
if( ! std::isfinite( suggested_next_timestep_ ) ) { // check for NaN
suggested_next_timestep_ = timestep;
}
return report;
}
void AdaptiveTimeStepping::
stepImpl( const SimulatorTimer& simulatorTimer,
Solver& solver, State& state, WState& well_state,
OutputWriter* outputWriter )
{
const double timestep = simulatorTimer.currentStepLength();
// init last time step as a fraction of the given time step
if( last_timestep_ < 0 ) {
last_timestep_ = restart_factor_ * timestep;
}
// TODO
// take change in well state into account
// create adaptive step timer with previously used sub step size
AdaptiveSimulatorTimer substepTimer( simulatorTimer, last_timestep_, max_time_step_ );
// copy states in case solver has to be restarted (to be revised)
State last_state( state );
WState last_well_state( well_state );
// counter for solver restarts
int restarts = 0;
// sub step time loop
while( ! substepTimer.done() )
{
// get current delta t
const double dt = substepTimer.currentStepLength() ;
// initialize time step control in case current state is needed later
timeStepControl_->initialize( state );
if( timestep_verbose_ )
{
std::cout <<"Substep( " << substepTimer.currentStepNum() << " ), try with stepsize "
<< unit::convert::to(substepTimer.currentStepLength(), unit::day) << " (days)." << std::endl;
}
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 (const Opm::NumericalProblem& e) {
std::cerr << e.what() << std::endl;
// since linearIterations is < 0 this will restart the solver
}
catch (const std::runtime_error& e) {
std::cerr << e.what() << std::endl;
// also catch linear solver not converged
}
// (linearIterations < 0 means no convergence in solver)
if( linearIterations >= 0 )
{
// advance by current dt
++substepTimer;
// compute new time step estimate
double dtEstimate =
timeStepControl_->computeTimeStepSize( dt, linearIterations, state );
// avoid time step size growth
if( restarts > 0 ) {
dtEstimate = std::min( growth_factor_ * dt, dtEstimate );
// solver converged, reset restarts counter
restarts = 0;
}
if( timestep_verbose_ )
{
std::cout << "Substep( " << substepTimer.currentStepNum()-1 // it was already advanced by ++
<< " ) finished at time " << unit::convert::to(substepTimer.simulationTimeElapsed(),unit::day) << " (days)." << std::endl << std::endl;
}
// write data if outputWriter was provided
if( outputWriter ) {
outputWriter->writeTimeStep( substepTimer, state, well_state );
}
// set new time step length
substepTimer.provideTimeStepEstimate( dtEstimate );
// update states
last_state = state ;
last_well_state = well_state;
}
else // in case of no convergence (linearIterations < 0)
{
// 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
substepTimer.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 max of the small time step for next reportStep
last_timestep_ = substepTimer.averageStepLength();
if( timestep_verbose_ )
{
substepTimer.report( std::cout );
std::cout << "Suggested next step size = " << unit::convert::to( last_timestep_, unit::day ) << " (days)" << std::endl;
}
if( ! std::isfinite( last_timestep_ ) ) { // check for NaN
last_timestep_ = timestep;
}
}
