Defining electrical properties for different regions from gmsh

General Discussion
1

Hello colleagues

I have imported a 3D mesh from gmsh with different physical volumes inside it in freefem, all are imported in one mesh.
I need to define different epsilon on each region. I can get my physical volumes tages by command

fespace Ph(Th, P1); Ph reg = region; plot(reg); real[int] tags; Unique(reg[], tags); cout << "tags"<<tags << endl;

May you suggest me a command so to define epsilons for each region based on physical volumes tags?

Thanks in advance.

2

You’ve probably already figured it out, but if you’re still looking for an answer (untested code):

fespace V0(Th, P0);

// region tags
int air1 = 3;
int porcelain1 = 4;
int air2 = 5;

real eps0 = 8.8541878128e-12;
real epsr_air = 1.00059;
real epsr_porcelain = 4;

V0 eps = eps0 * ( epsr_air *(region == air1 || region == air2) +
                epsr_porcelain * (region == porcelain1) );
3

Thanks alot for your response,

So eps considers separate permittivity of each region?