I have been trying to compute integral on a label surface Sr using imported mesh from GMSH.
There are 2 surfaces : Sr and Si.
Several elements are on Sr AND Si and other only on Sr or Si. They are (normally) well defined in the .msh file following:
Element id - Element dimension - Number of tags - < Tags > - Nodes
When I try to compute:
int2d(Th,Sr) (1.) ,
it only integrates on elements which are only on Sr. Elements which are on Sr AND Si are not taken into account.
It may be a basic problem but I haven’t found similar issues. Sorry if solution has been already provided.
You need to compute
It’s not what I am looking for. Sorry, it may be not clear.
I want to integrate on all elements of Sr.
But in the definition of the elements in .msh file, some belong to Sr (case 1), and some belong Sr and Si (case 2), such as:
Element Id - 2 - 1 - Sr - Nodes
Element Id - 2 - 2 - Sr - Si - Nodes
Elements of case 2 are not taken into account in the integral.
In FreeFEM, elements only have a single region. Boundary elements have only a single label. If
Si are boundary element labels, my answer still holds.
In FreeFEM, elements only have a single region.
I ignored that. Thank you. I managed to do it in a different way by creating an other label : SrSi ( Sr ∩ Si ).
And I integrate on Sr and Sr ∩ Si :