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// ------------------------------------------------------------------------
//
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2010 - 2024 by the deal.II authors
//
// This file is part of the deal.II library.
//
// Part of the source code is dual licensed under Apache-2.0 WITH
// LLVM-exception OR LGPL-2.1-or-later. Detailed license information
// governing the source code and code contributions can be found in
// LICENSE.md and CONTRIBUTING.md at the top level directory of deal.II.
//
// ------------------------------------------------------------------------
#include <deal.II/algorithms/timestep_control.h>
#include <deal.II/base/parameter_handler.h>
DEAL_II_NAMESPACE_OPEN
namespace Algorithms
{
TimestepControl::TimestepControl(double start,
double final,
double tolerance,
double start_step,
double print_step,
double max_step)
: start_val(start)
, final_val(final)
, tolerance_val(tolerance)
, start_step_val(start_step)
, max_step_val(max_step)
, min_step_val(0)
, current_step_val(start_step)
, step_val(start_step)
, print_step(print_step)
, next_print_val(print_step > 0. ? start_val + print_step : start_val - 1.)
{
now_val = start_val;
// avoid compiler warning
(void)min_step_val;
}
void
TimestepControl::declare_parameters(ParameterHandler ¶m)
{
param.declare_entry("Start", "0.", Patterns::Double());
param.declare_entry("Final", "1.", Patterns::Double());
param.declare_entry("First step", "1.e-2", Patterns::Double(0.));
param.declare_entry("Max step", "1.", Patterns::Double(0.));
param.declare_entry("Tolerance", "1.e-2", Patterns::Double(0.));
param.declare_entry("Print step", "-1.", Patterns::Double());
}
void
TimestepControl::parse_parameters(const ParameterHandler ¶m)
{
start(param.get_double("Start"));
start_step(param.get_double("First step"));
max_step(param.get_double("Max step"));
final(param.get_double("Final"));
tolerance(param.get_double("Tolerance"));
print_step = param.get_double("Print step");
}
bool
TimestepControl::advance()
{
bool changed = false;
// Try incrementing time by s
double now_trial = now_val + step_val;
current_step_val = step_val;
// If we just missed the final time, increase the step size a bit. This way,
// we avoid a very small final step. If the step shot over the final time,
// adjust it so we hit the final time exactly.
double s1 = .01 * step_val;
if (now_trial > final_val - s1)
{
current_step_val = final_val - now_val;
now_trial = final_val;
changed = true;
}
now_val = now_trial;
return changed;
}
bool
TimestepControl::print()
{
if (print_step == 0.)
return false;
if (print_step < 0.)
return true;
bool result = (now_val >= next_print_val);
if (result)
{
next_print_val += print_step;
if (next_print_val > final_val)
next_print_val = final_val;
}
return result;
}
} // namespace Algorithms
DEAL_II_NAMESPACE_CLOSE
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