public virtual Vector[] Calculate_ElementNodal_DUDX()
{
double[] Ue = Get_ElementNodal_U();
Vector[] Xi = Interpolator.Calculate_ElementNodal_Xi();
int NNPE = Xi.Length;
Vector[] DUDX = new Vector[NNPE];
for (int i = 0; i < NNPE; i++)
{
DUDX[i] = Interpolator.Interpolate_DerivativeOfVariable_WRTX(Xi[i], Ue, ElementNodes);
}
return(DUDX);
}