Dear NGSolve community,
I am new to NGSolve and I'd like to ask two basic questions.
1. How can I get the ordering of the basis functions on each element?
I know we can use
to get the DOF number for each element. But I wonder how can I know what basis function corresponds to a given DOF. For example, I am using L2 space for quadrilateral meshes. I know the L2 space uses a tensor product of Legendre Polynomials in x and y directions. But I notice that in some elements, the basis functions are ordering like 1, y, x, x*y...., while in some other element, they are ordering like 1, x, y, x*y. Is there an easy way to know the ordering of the basis functions in each element?
2. Can I do interpolation with a set of points?
I know we can use
GridFunction.Set to interpolate a
CoefficientFunction, but I wonder if I have a set of points and values (x_i, y_i, eval_i), can I interpolate (or do least squares) to an element in the finite element space?
Thank you for answering my questions.
Best,
Oliver