You know when we compute an integration int2D( ) on a triangle, we usually transform it to a standard reference triangle to compute it.
We can easily use the shape function to do the transformation (isoparametric transformation).
My question is:
Does FreeFem++ use the shape functions (can be second order or higher) to do the transformation?
If so, I am thinking about the boundary of a circle which can be accurately represented by the P2 element…