Isoparametric Elements

Hello everyone,

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…


SRory not today because I do not have this informartion in the mesh,

This is a huge change

how similar is this to conformal mapping?

I tested the mesh convergence for a fluid problem using P2P1 elements and I cannot get the order of optimal convergence for the velocity: the order of L2 error for velocity is about 1.5, which is far from 3.