OOF2: The Manual
Name
Adaptive (AdaptiveDriver) — Take variable sized timesteps.
Synopsis
AdaptiveDriver
(tolerance
,initialstep
,minstep
,errorscaling
,stepper
)
Details

Base class:
StepDriver

Parameters:
tolerance
 Maximum permissable error. Type: A real number.
initialstep
 Initial step size. Type: A real number.
minstep
 Minimum time step size. Type: A real number.
errorscaling
 How to compute the error for each degree of freedom. Type: An object of the
StepErrorScaling
class. stepper
 Time stepping method. Type: An object of the
QCTimeStepper
class.
Description
AdaptiveDriver
objects are used as the
time_stepper
parameter in AdvancedSolverMode when solving a
timedependent problem with adaptive time
stepping. The AdaptiveDriver
uses the
given stepper
to take single steps. If the
resulting error estimate is larger than the given
tolerance
, the step is rejected and is repeated
with a smaller . If the error is
less than the tolerance
, the
step size will be increased on the next step.
initialstep
is the step size to use at the
beginning of the computation. Once a computation is under way, the
step size is determined by the error estimate from the previous
step.
If the error cannot be reduced below tolerance
without using a step size below minstep
, the
computation will be aborted. Often this means that the problem is
badly posed, or that the errorscaling
is in
appropriate.
errorscaling
defines what is really meant by
“the error estimate is larger than the given
tolerance
”. It determines how a set of
errors in each Field
component value at each Node
is reduced to
a single number that can be compared with the
tolerance
.
AdaptiveDriver
plays the same role in AdvancedSolverMode that BasicAdaptiveDriver plays in BasicSolverMode.