public IMatrix BuildStiffnessMatrix()
{
int numberOfDofs = 3 * Nodes.Count;
var stiffness = Matrix.CreateZero(numberOfDofs, numberOfDofs);
IReadOnlyList <Matrix> shapeGradientsNatural =
Interpolation.EvaluateNaturalGradientsAtGaussPoints(QuadratureForStiffness);
for (int gp = 0; gp < QuadratureForStiffness.IntegrationPoints.Count; ++gp)
{
IMatrixView constitutive = materialsAtGaussPoints[gp].ConstitutiveMatrix;
var jacobian = new IsoparametricJacobian3D(Nodes, shapeGradientsNatural[gp]);
Matrix shapeGradientsCartesian =
jacobian.TransformNaturalDerivativesToCartesian(shapeGradientsNatural[gp]);
Matrix deformation = BuildDeformationMatrix(shapeGradientsCartesian);
Matrix partial = deformation.ThisTransposeTimesOtherTimesThis(constitutive);
double dA = jacobian.DirectDeterminant * QuadratureForStiffness.IntegrationPoints[gp].Weight;
stiffness.AxpyIntoThis(partial, dA);
}
return(DofEnumerator.GetTransformedMatrix(stiffness));
}
public IMatrix DiffusionConductivityMatrix(IElement element)
{
return(DofEnumerator.GetTransformedMatrix(BuildDiffusionConductivityMatrix()));
}
public IMatrix MassTransportConductivityMatrix(IElement element)
{
return(DofEnumerator.GetTransformedMatrix(BuildMassTransportConductivityMatrix()));
}
public double[] GetLocalDOFValues(Element hostElement, double[] hostDOFValues)
{
return(DofEnumerator.GetTransformedDisplacementsVector(hostDOFValues));
}
public IMatrix DampingMatrix(IElement element)
{
return(DofEnumerator.GetTransformedMatrix(BuildStabilizingConductivityMatrix() +
BuildStabilizingLoadFromUnknownConductivityMatrix()));
//return BuildStabilizingConductivityMatrix();
}
public IMatrix StiffnessMatrix(IElement element)
{
return(DofEnumerator.GetTransformedMatrix(BuildDiffusionConductivityMatrix() + BuildMassTransportConductivityMatrix() +
BuildLoadFromUnknownConductivityMatrix()));
//return BuildDiffusionConductivityMatrix() + BuildMassTransportConductivityMatrix();
}
public IMatrix StiffnessMatrix(IElement element) => DofEnumerator.GetTransformedMatrix(BuildStiffnessMatrix());
public IMatrix StiffnessMatrix(IElement element)
{
return(DofEnumerator.GetTransformedMatrix(BuildConductivityMatrix()));
}
public IMatrix StiffnessMatrix(IElement element)
{
return(DofEnumerator.GetTransformedMatrix(BuildDiffusionMatrix()));
}
