/// <summary>
/// Accumulates the DG-projection (with respect to the DG-basis
/// of this field, <see cref="Basis"/>) of
/// <paramref name="alpha"/>*<paramref name="f"/>^<paramref name="pow"/> to this field;
/// </summary>
/// <param name="alpha">scaling for accumulation</param>
/// <param name="f">operand</param>
/// <param name="pow">exponent</param>
/// <param name="em">
/// An optional restriction to the domain in which the projection is
/// computed (it may, e.g. be only required in boundary cells, so a
/// computation over the whole domain would be a waste of computation
/// power. A proper execution mask would be see e.g.
/// <see cref="GridData.BoundaryCells"/>.)
/// if null, the computation is carried out in the whole domain;
/// </param>
virtual public void ProjectPow(double alpha, DGField f, double pow, CellMask em)
{
if (!object.ReferenceEquals(f.Basis.GridDat, this.Basis.GridDat))
{
throw new ArgumentException("field is associated to another context.", "a");
}
SpatialOperator powOp = new SpatialOperator(new string[] { "f" },
new string[] { "res" },
QuadOrderFunc.SumOfMaxDegrees());
powOp.EquationComponents["res"].Add(new PowSource(pow));
powOp.Commit();
CoordinateVector coDom = this.CoordinateVector;
var ev = powOp.GetEvaluatorEx(
new CoordinateMapping(f), null, coDom.Mapping,
edgeQrCtx: new EdgeQuadratureScheme(true, EdgeMask.GetEmptyMask(this.Basis.GridDat)),
volQrCtx: new CellQuadratureScheme(true, em));
ev.Evaluate <CoordinateVector>(alpha, 1.0, coDom); // only sources, no edge integrals required
}
/// <summary>
/// accumulates the projection of some vector field to this field, i.e.
/// \f[
/// this = this + \alpha \cdot \| \vec{vec} \|.
/// \f]
/// </summary>
/// <param name="alpha">factor \f$ \alpha \f$ </param>
/// <param name="vec">vector field \f$ \vec{vec} \f$ </param>
/// <param name="em">
/// An optional restriction to the domain in which the projection is computed (it may, e.g.
/// be only required in boundary cells, so a computation over the whole domain
/// would be a waste of computation power. If null, the computation is carried out in the whole domain;
/// </param>
virtual public void ProjectAbs(double alpha, CellMask em, params DGField[] vec)
{
int K = vec.Length;
string[] args = new string[K];
for (int k = 0; k < K; k++)
{
args[k] = "_" + k;
}
SpatialOperator powOp = new SpatialOperator(args, new string[] { "res" }, QuadOrderFunc.SumOfMaxDegrees());
powOp.EquationComponents["res"].Add(new AbsSource(args));
powOp.EdgeQuadraturSchemeProvider = g => new EdgeQuadratureScheme(true, EdgeMask.GetEmptyMask(this.Basis.GridDat));
powOp.VolumeQuadraturSchemeProvider = g => new CellQuadratureScheme(true, em);
powOp.Commit();
CoordinateVector coDom = new CoordinateVector(this);
var ev = powOp.GetEvaluatorEx(
new CoordinateMapping(vec),
null,
coDom.Mapping);
ev.Evaluate <CoordinateVector>(alpha, 1.0, coDom); // only sources, no edge integrals required
}