/// <summary>
/// Updates the time history of the entire cluster (if <see cref="adaptive"/>== false), or
/// of each cell (if <see cref="adaptive"/>== true)
/// </summary>
/// <param name="dt"></param>
protected virtual void UpdateTimeHistory(double dt)
{
using (new ilPSP.Tracing.FuncTrace("UpdateTimeHistory")) {
if (adaptive)
{
double[] currentTime = new double[ABSubGrid.LocalNoOfCells];
for (int i = 0; i < currentTime.Length; i++)
{
currentTime[i] = m_Time;
}
historyTimePerCell.Enqueue(currentTime);
if (historyTimePerCell.Count > order - 1) //eventuell nicht nötig, später mal überprüfen
{
historyTimePerCell.Dequeue();
}
}
else
{
HistoryTime.Enqueue(m_Time + dt); // --> später noch schön machen und ähnlich wie timeHistoryPerCell, einen eintrag weglassen, weil das eh m_time ist!
if (HistoryTime.Count >= order) //eventuell nicht nötig, später mal überprüfen
{
HistoryTime.Dequeue();
}
}
}
}
/// <summary>
/// performs one time step
/// </summary>
/// <param name="dt">size of time step</param>
public override double Perform(double dt)
{
using (new ilPSP.Tracing.FuncTrace()) {
if (TimeStepConstraints != null)
{
dt = CalculateTimeStep();
}
// new array object needed, because currentChangeRate from last time steps are stored in historyCR queue (in queues are only references of the array)
CurrentChangeRate = new double[Mapping.LocalLength];
CompleteChangeRate = new double[Mapping.LocalLength];
// AB only possible if history with "order-1" entries exists
// e.g: order=3 needs t_n (currentChangeRate), t_n-1 (history(2)), t_n-2 (history(1)) --> history has 2 entries
if (HistoryChangeRate.Count >= order - 1)
{
ABCoefficients = ComputeCoefficients(dt, HistoryTime.ToArray());
ComputeChangeRate(CurrentChangeRate, m_Time, 0);
//y <-- alpha*x + y
BLAS.daxpy(CompleteChangeRate.Length, ABCoefficients[0], CurrentChangeRate, 1, CompleteChangeRate, 1);
// calculate completeChangeRate
int i = 1;
foreach (double[] oldRate in HistoryChangeRate)
{
BLAS.daxpy(CompleteChangeRate.Length, ABCoefficients[i], oldRate, 1, CompleteChangeRate, 1);
i++;
}
// perform time step
CurrentState.axpy <double[]>(CompleteChangeRate, -1);
m_Time += dt;
HistoryTime.Enqueue(m_Time);
HistoryTime.Dequeue();
HistoryChangeRate.Enqueue(CurrentChangeRate);
HistoryChangeRate.Dequeue();
}
else
{
if (HistoryTime.Count == 0)
{
HistoryTime.Enqueue(RungeKuttaScheme.Time);
}
// Needed for the history
ComputeChangeRate(CurrentChangeRate, m_Time, 0);
// RungeKutta with order+1 starts the time stepping
RungeKuttaScheme.Perform(dt);
// Disposal RK after "order" of time steps
if (HistoryChangeRate.Count == order - 1)
{
RungeKuttaScheme = null;
}
m_Time = RungeKuttaScheme.Time;
HistoryTime.Enqueue(RungeKuttaScheme.Time);
HistoryChangeRate.Enqueue(CurrentChangeRate);
}
}
return(dt);
}
