Commit ba21ae89 authored by mattijs's avatar mattijs
Browse files

ENH: timeControl: adds some more #423.

parent 5f36999c
......@@ -51,9 +51,20 @@ void Foam::functionObjects::timeControl::readControls()
{
timeEnd_ = time_.userTimeToTime(timeEnd_);
}
deltaTCoeff_ = dict_.lookupOrDefault("deltaTCoeff", GREAT);
dict_.readIfPresent("nStepsToStartTimeChange", nStepsToStartTimeChange_);
deltaTCoeff_ = GREAT;
if (dict_.readIfPresent("deltaTCoeff", deltaTCoeff_))
{
nStepsToStartTimeChange_ = labelMax;
}
else
{
nStepsToStartTimeChange_ = 3;
dict_.readIfPresent
(
"nStepsToStartTimeChange",
nStepsToStartTimeChange_
);
}
}
......@@ -73,7 +84,6 @@ Foam::scalar Foam::functionObjects::timeControl::calcExpansion
)
{
scalar ratio = startRatio;
// This function is used to calculate the 'expansion ratio' or
// 'time step growth factor'. Inputs:
// - ratio: wanted ratio
......@@ -156,7 +166,7 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
/(requiredDeltaTCoeff - 1);
}
// Nearest time which is multiple of wantedDT, after
// Nearest time which is multiple of wantedDT, after
// requiredTimeInterval
scalar timeToNextMultiple = -presentTime;
......@@ -185,7 +195,7 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
if (timeToNextWrite <= timeToNextMultiple)
{
// As the ramping can't be achieved, use current, unadapted deltaT
// (from e.g. maxCo calculation in solver) and adjust when
// (from e.g. maxCo calculation in solver) and adjust when
// writeInterval is closer than this deltaT
newDeltaT = deltaT0_;
if (timeToNextWrite < newDeltaT)
......@@ -220,13 +230,12 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
}
else
{
// Find the minimum number of time steps (with constant deltaT
// Find the minimum number of time steps (with constant deltaT
// variation) to get us to the writeInterval and multiples of wantedDT.
// Increases the number of nSteps to do the adjustment in until it
// has reached one that is possible. Returns the new expansionratio.
scalar y = timeToNextMultiple/wantedDT;
label requiredSteps = nSteps;
scalar ratioEstimate = deltaTCoeff_;
......@@ -240,6 +249,7 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
if (!rampDirectionUp)
{
ratioEstimate = 1/ratioEstimate;
ratioMax = 1/ratioMax;
requiredSteps *= -1;
}
// Provision for fall-back value if we can't satisfy requirements
......@@ -253,16 +263,18 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
y,
requiredSteps
);
const scalar deltaTLoop = wantedDT/pow(newRatio, requiredSteps-1);
const scalar deltaTLoop =
wantedDT
/ pow(newRatio, mag(requiredSteps)-1);
scalar firstDeltaRatio = deltaTLoop/deltaT0_;
// Avoid division by zero for ratio = 1.0
scalar Sn =
deltaTLoop
*(pow(newRatio, mag(requiredSteps))-1)
/(newRatio-1+SMALL);
if (debug)
{
// Avoid division by zero for ratio = 1.0
scalar Sn =
deltaTLoop
*(pow(newRatio, requiredSteps)-1)
/(newRatio-1+SMALL);
Info<< " nSteps " << requiredSteps
<< " ratioEstimate " << ratioEstimate
<< " a0 " << deltaTLoop
......@@ -281,7 +293,7 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
)
{
y += 1;
requiredSteps = nSteps;
requiredSteps = mag(nSteps);
if (debug)
{
Info<< "firstDeltaRatio " << firstDeltaRatio << " rampDir"
......@@ -291,7 +303,7 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
continue;
}
if (firstDeltaRatio > ratioMax)
if (firstDeltaRatio > ratioMax && rampDirectionUp)
{
requiredSteps++;
if (debug)
......@@ -302,7 +314,22 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
<< endl;
}
}
else if (newRatio > ratioMax)
else if (firstDeltaRatio < ratioMax && !rampDirectionUp)
{
requiredSteps--;
if (debug)
{
Info<< "First ratio " << firstDeltaRatio
<< " exceeds threshold " << ratioMax << nl
<< "Decreasing required steps " << requiredSteps
<< endl;
}
}
else if
(
(newRatio > ratioMax && rampDirectionUp)
|| (newRatio < ratioMax && !rampDirectionUp)
)
{
y += 1;
requiredSteps = nSteps;
......@@ -319,8 +346,19 @@ void Foam::functionObjects::timeControl::calcDeltaTCoeff
// Reset future series expansion at last step
if (requiredSteps == 1)
{
Sn = deltaT0_*firstDeltaRatio;
seriesDTCoeff_ = GREAT;
}
// Situations where we achieve wantedDT but fail to achieve
// multiple of writeInterval
scalar jumpError =
remainder(Sn + presentTime, wantedDT) / wantedDT;
if (mag(jumpError) > ROOTSMALL)
{
requiredSteps = label(timeToNextWrite/wantedDT);
firstDeltaRatio = timeToNextWrite/requiredSteps/deltaT0_;
}
if (debug)
{
Info<< "All conditions satisfied deltaT0_:" << deltaT0_
......@@ -365,10 +403,7 @@ Foam::functionObjects::timeControl::timeControl
dict_(dict),
timeStart_(-VGREAT),
timeEnd_(VGREAT),
nStepsToStartTimeChange_
(
dict.lookupOrDefault("nStepsToStartTimeChange", 3)
),
nStepsToStartTimeChange_(labelMax),
executeControl_(t, dict, "execute"),
writeControl_(t, dict, "write"),
foPtr_(functionObject::New(name, t, dict_)),
......@@ -484,7 +519,7 @@ bool Foam::functionObjects::timeControl::adjustTimeStep()
// too strict.
scalar intervalError =
remainder(writeInterval, wantedDT)/writeInterval;
if
if
(
mag(intervalError) > ROOTSMALL
|| deltaTCoeff_ == GREAT
......@@ -494,7 +529,14 @@ bool Foam::functionObjects::timeControl::adjustTimeStep()
scalar nSteps = timeToNextWrite/deltaT;
// For tiny deltaT the label can overflow!
if (nSteps < labelMax)
if
(
nSteps < labelMax
&& (
deltaTCoeff_ != GREAT
|| nSteps < nStepsToStartTimeChange_
)
)
{
// nSteps can be < 1 so make sure at least 1
......@@ -517,6 +559,7 @@ bool Foam::functionObjects::timeControl::adjustTimeStep()
clipThreshold = 1/clipThreshold;
deltaT = max(newDeltaT, clipThreshold*deltaT);
}
const_cast<Time&>(time_).setDeltaT(deltaT, false);
}
}
......@@ -569,12 +612,12 @@ bool Foam::functionObjects::timeControl::adjustTimeStep()
)
);
}
// Negative steps -> ramp down needed,
// Negative steps -> ramp down needed,
// zero steps -> we are at writeInterval-multiple time!
if (nSteps < 1)
{
// Not enough steps to do gradual time step adjustment
// if earlier deltaT larger than wantedDT
// if earlier deltaT larger than wantedDT
if (wantedDT < deltaT0_)
{
requiredDeltaTCoeff = 1/requiredDeltaTCoeff;
......@@ -582,7 +625,7 @@ bool Foam::functionObjects::timeControl::adjustTimeStep()
(
requiredDeltaTCoeff,
wantedDT,
nSteps,
nSteps,
presentTime,
timeToNextWrite,
false
......@@ -614,7 +657,7 @@ bool Foam::functionObjects::timeControl::adjustTimeStep()
(
requiredDeltaTCoeff,
wantedDT,
nSteps,
nSteps,
presentTime,
timeToNextWrite,
true
......@@ -635,7 +678,7 @@ bool Foam::functionObjects::timeControl::adjustTimeStep()
}
}
}
else
else
{
foPtr_->adjustTimeStep();
const scalar wantedDT = time_.deltaTValue();
......
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