Only executed when the function create.FEM.basis is run with the option CPP_CODE = FALSE.
It computes some quantities associated to the linear map that transforms the ith triangle in the reference triangular element.
These are used for the computation of the integrals necessary to build the mass and stiffness matrix.
R_elementProperties(mesh)A MESH2D mesh object representing the triangular mesh. This can be created with create.MESH.2D.
A list with the following variables:
detJA vector of length #triangles. The ith element contains the determinant of the transformation from the reference triangle to the nodes of the i-th triangle. It's values is also the double of the area of each triangle of the basis.
transfA matrix #triangles-by-2-by-2. transf[i,,] is the 2-by-2 tranformation matrix that transforms the nodes of the reference triangle to the nodes of the i-th triangle.
metricA matrix #triangles-by-2-by-2. metric[i,,] is the 2-by-2 matrix
transf[i,,]^{-1}*transf[i,,]^{-T}. This matrix is usuful for the computation
of the integrals over the elements of the mesh.