From 68321ffd0d35cabd3ee0587ec16fbd582a83f43a Mon Sep 17 00:00:00 2001
From: Wenqing Wang <wenqing.wang@ufz.de>
Date: Thu, 17 Aug 2017 11:46:08 +0200
Subject: [PATCH] [dt] Added a documentation to
EvolutionaryPIDcontroller::limitStepSize
---
.../Algorithms/EvolutionaryPIDcontroller.cpp | 12 +++++++-----
.../Algorithms/EvolutionaryPIDcontroller.h | 13 ++++++++++++-
2 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.cpp b/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.cpp
index 54e4ae16e69..ed545e4e46f 100644
--- a/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.cpp
+++ b/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.cpp
@@ -34,8 +34,7 @@ bool EvolutionaryPIDcontroller::next(const double solution_error)
double h_new = (e_n > zero_threshlod) ? _ts_current.dt() * _tol / e_n
: 0.5 * _ts_current.dt();
- h_new =
- limitStepSize(h_new, _ts_current.dt(), is_previous_step_accepted);
+ h_new = limitStepSize(h_new, is_previous_step_accepted);
h_new = checkSpecificTimeReached(h_new);
_ts_current = _ts_prev;
@@ -95,7 +94,7 @@ bool EvolutionaryPIDcontroller::next(const double solution_error)
}
}
- h_new = limitStepSize(h_new, h_n, is_previous_step_accepted);
+ h_new = limitStepSize(h_new, is_previous_step_accepted);
h_new = checkSpecificTimeReached(h_new);
_dt_vector.push_back(h_new);
@@ -110,10 +109,13 @@ bool EvolutionaryPIDcontroller::next(const double solution_error)
}
double EvolutionaryPIDcontroller::limitStepSize(
- const double h_new, const double h_n,
- const bool previous_step_accepted) const
+ const double h_new, const bool previous_step_accepted) const
{
+ const double h_n = _ts_current.dt();
+ // Forced the computed time step size in the given range
+ // (see the formulas in the documentation of the class)
const double h_in_range = std::max(_h_min, std::min(h_new, _h_max));
+ // Limit the step size change ratio.
double limited_h =
std::max(_rel_h_min * h_n, std::min(h_in_range, _rel_h_max * h_n));
diff --git a/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.h b/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.h
index 5f0581b9671..971de4ef5ce 100644
--- a/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.h
+++ b/NumLib/TimeStepping/Algorithms/EvolutionaryPIDcontroller.h
@@ -115,7 +115,18 @@ private:
bool _is_accepted;
- double limitStepSize(const double h_new, const double h_n,
+ /**
+ * Forced the computed time step size in the given range
+ * (see the formulas in the documentation of the class)
+ * or use the half of the previous time step size under some other
+ * constrains.
+ * @param h_new The computed time step size.
+ * @param previous_step_accepted An indicator for whether the previous time
+ * step is rejected.
+ * @return The new time step after apply
+ * the constrains.
+ */
+ double limitStepSize(const double h_new,
const bool previous_step_accepted) const;
double checkSpecificTimeReached(const double h_new);
--
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