double[,] BuildLocalMatrix(FiniteElement e)
{
Point p1 = Mesh.Points[e[0]];
Point p2 = Mesh.Points[e[1]];
Point p3 = Mesh.Points[e[2]];
double hx = p2.X - p1.X;
double hy = p3.Y - p1.Y;
double mes = hx * hy;
double avgB = GetAverageB(e);
double mu = e.Material.Mu(avgB);
double muDer = e.Material.MuDer(avgB);
double[,] G = new double[FEMParameters.BasisSize, FEMParameters.BasisSize];
double lambda = 1.0 / mu;
// Calculate G(q0)
for (int i = 0; i < FEMParameters.BasisSize; i++)
{
for (int j = 0; j < FEMParameters.BasisSize; j++)
{
G[i, j] = lambda * P[i, j];
}
}
if (!FloatComparision.IsEqual(0.0, muDer))
{
// Calculate sums
double der = -muDer / (mu * mu * 2 * avgB);
for (int i = 0; i < FEMParameters.BasisSize; i++)
{
for (int r = 0; r < FEMParameters.BasisSize; r++)
{
double sum1 = 0;
for (int s = 0; s < FEMParameters.BasisSize; s++)
{
sum1 += P[i, s] * q[e[s]];
}
double sum2 = 0;
for (int p = 0; p < FEMParameters.BasisSize; p++)
{
sum2 += P[r, p] * q[e[p]];
}
G[i, r] += 2.0 * der * sum1 * sum2 / mes;
}
}
}
return(G);
}
double[] BuildLocalB(FiniteElement e)
{
Point p1 = Mesh.Points[e[0]];
Point p2 = Mesh.Points[e[1]];
Point p3 = Mesh.Points[e[2]];
double hx = p2.X - p1.X;
double hy = p3.Y - p1.Y;
double mes = hx * hy;
double avgB = GetAverageB(e);
double mu = e.Material.Mu(avgB);
double muDer = e.Material.MuDer(avgB);
double[] B = new double[FEMParameters.BasisSize];
double J = e.Material.J;
// Calculate b(q0)
for (int i = 0; i < FEMParameters.BasisSize; i++)
{
for (int j = 0; j < FEMParameters.BasisSize; j++)
{
B[i] += localM[i, j] * J;
}
}
for (int i = 0; i < FEMParameters.BasisSize; i++)
{
B[i] *= hx * hy / 36;
}
if (!FloatComparision.IsEqual(0.0, muDer))
{
double der = -muDer / (mu * mu * 2 * avgB);
// Calculate sum
for (int i = 0; i < FEMParameters.BasisSize; i++)
{
double sum1 = 0;
for (int s = 0; s < FEMParameters.BasisSize; s++)
{
sum1 += P[i, s] * q[e[s]];
}
double sum2 = 0;
for (int r = 0; r < FEMParameters.BasisSize; r++)
{
double sum = 0;
for (int p = 0; p < FEMParameters.BasisSize; p++)
{
sum += P[r, p] * q[e[p]];
}
sum2 += q[e[r]] * sum;
}
B[i] += 2.0 * der * sum1 * sum2 / mes;
}
}
return(B);
}
