/// <summary>
/// Addition/Subtraction of DG fields on different grids
/// </summary>
/// <param name="A"></param>
/// <param name="scaleA"></param>
/// <param name="B"></param>
/// <param name="scaleB"></param>
/// <returns>
/// <paramref name="scaleA"/>*<paramref name="A"/> + <paramref name="scaleB"/>*<paramref name="B"/>
/// </returns>
static public DGField ScaledSummation(this DGField A, double scaleA, DGField B, double scaleB)
{
if (object.ReferenceEquals(A.GridDat, B.GridDat))
{
// ++++++++++++++++++++++++++++
// both fields on the same grid
// ++++++++++++++++++++++++++++
DGField sum;
if (A.Basis.IsSubBasis(B.Basis))
{
sum = (DGField)B.Clone();
sum.Scale(scaleB);
sum.AccLaidBack(1.0, A);
}
else if (B.Basis.IsSubBasis(A.Basis))
{
sum = (DGField)A.Clone();
sum.Scale(scaleA);
sum.AccLaidBack(1.0, B);
}
else
{
throw new ApplicationException("can't add the two fields, because their basis are incompatible");
}
sum.Identification = "(" + scaleA + "*" + A.Identification + "+" + scaleB + "*" + B.Identification + ")";
return(sum);
}
else
{
// ++++++++++++++++++++++++++
// fields on different grids
// ++++++++++++++++++++++++++
DGField fine, coarse;
double aF, aC;
if (A.GridDat.CellPartitioning.TotalLength > B.GridDat.CellPartitioning.TotalLength)
{
fine = A;
coarse = B;
aF = scaleA;
aC = scaleB;
}
else
{
coarse = A;
fine = B;
aC = scaleA;
aF = scaleB;
}
DGFieldComparison.ComputeFine2CoarseMap(
(Foundation.Grid.Classic.GridData)(fine.GridDat),
(Foundation.Grid.Classic.GridData)(coarse.GridDat),
out var Fine2CoarseMapS);
DGField injected;
if (coarse is ConventionalDGField)
{
ConventionalDGField _injected = new SinglePhaseField(
new Basis(fine.GridDat, Math.Max(coarse.Basis.Degree, fine.Basis.Degree)),
coarse.Identification);
DGFieldComparison.InjectDGField(Fine2CoarseMapS, _injected, coarse as ConventionalDGField);
injected = _injected;
}
else if (coarse is XDGField)
{
XDGField _injected = new XDGField(
new XDGBasis((fine as XDGField).Basis.Tracker, Math.Max(coarse.Basis.Degree, fine.Basis.Degree)),
coarse.Identification);
DGFieldComparison.InjectXDGField(Fine2CoarseMapS, _injected, coarse as XDGField);
injected = _injected;
}
else
{
throw new NotSupportedException();
}
return(ScaledSummation(injected, aC, fine, aF));
}
}
