private void RKstage(double dt, double[][] k, int s, BlockMsrMatrix MsInv, BlockMsrMatrix M0, double[] u0, double[] coefficients)
{
// Copy coordinates to temp array since SpMV (below) does not
// support in-place computation
double[] tempCoordinates = DGCoordinates.ToArray();
M0.SpMV(1.0, u0, 0.0, tempCoordinates); // Non-agglomerated
for (int l = 0; l < s; l++)
{
tempCoordinates.AccV(-coefficients[l] * dt, k[l]); // Non-agglomerated
}
speciesMap.Agglomerator.ManipulateRHS(tempCoordinates, Mapping);
MsInv.SpMV(1.0, tempCoordinates, 0.0, DGCoordinates);
speciesMap.Agglomerator.Extrapolate(DGCoordinates.Mapping);
}
public override double Perform(double dt)
{
if (TimeStepConstraints != null)
{
dt = CalculateTimeStep();
}
int NoOfStages = this.Scheme.Stages;
double[][] k = new double[NoOfStages][];
Mapping.Fields.ForEach(f => f.Clear(speciesMap.SubGrid.VolumeMask.Complement()));
UpdateEvaluatorsAndMasks();
AgglomerateAndExtrapolateDGCoordinates();
BlockMsrMatrix M0 = speciesMap.GetMassMatrixFactory(Mapping).NonAgglomeratedMassMatrix;
double[] u0 = DGCoordinates.ToArray(); // Lives on non-agglomerated mesh
// Initialize RK scheme
k[0] = new double[Mapping.LocalLength];
ComputeChangeRate(k[0], Time, 0.0);
// Intermediate stages
for (int stage = 1; stage < NoOfStages; stage++)
{
MoveLevelSetTo(Time + dt * this.Scheme.c[stage]);
UpdateEvaluatorsAndMasks();
AgglomerateAndExtrapolateDGCoordinates();
BlockMsrMatrix MsInverse = speciesMap.GetMassMatrixFactory(Mapping).InverseMassMatrix;
RKstage(dt, k, stage, MsInverse, M0, u0, this.Scheme.a.GetRow(stage));
k[stage] = new double[Mapping.LocalLength];
ComputeChangeRate(k[stage], Time, this.Scheme.c[stage] * dt);
}
// Final stage
MoveLevelSetTo(Time + dt);
UpdateEvaluatorsAndMasks();
BlockMsrMatrix M1Inverse = speciesMap.GetMassMatrixFactory(Mapping).InverseMassMatrix;
RKstage(dt, k, NoOfStages, M1Inverse, M0, u0, this.Scheme.b);
m_Time = Time + dt;
return(dt);
}
protected override double[] ComputesUpdatedDGCoordinates(double[] completeChangeRate)
{
double[] y0 = new double[Mapping.LocalLength];
DGCoordinates.CopyTo(y0, 0);
DGCoordinates.axpy <double[]>(completeChangeRate, -1);
// Speciality for IBM: Do the extrapolation
speciesMap.Agglomerator.Extrapolate(DGCoordinates.Mapping);
double[] upDGC = DGCoordinates.ToArray();
upDGC = OrderValuesBySgrd(upDGC);
// DGCoordinates should be untouched after calling this method
DGCoordinates.Clear();
DGCoordinates.CopyFrom(y0, 0);
return(upDGC);
}