Applying different valued matrix according to subdomain

General
1

Hi,
I am trying to calculate the effective thermal expansion coefficient (CTE) of a composite.
I am following a similar approach of homogenization example here.
I need to apply a thermal strain similar to Eps in the example. Where it is different for different materials.
So, how can i have a matrix with different values according to subdomain number?

2

Create a tensor function space of cellwise constant variables (DG 0).

3

Thanks for the response.
One additional query can fenics do interpolation with cells argument.
because i am using fenics.

4

No, that is not part of legacy fenics.

5

is there a way to do it in legacy fenics ?

6

Yes, in legacy fenics you can create a tensor for each Subdomain, for instance

E_0 = Constant(0.5)
E_1 = Constant(1.5)
t = as_tensor(((E_0,0),(E_0, E_1)))

and then use the integration measure to restrict integration, dx_c = Measure("dx", domain=mesh, subdomain_data=cell_marker)
and use dx(j) to restrict the integration to the cells marked with j.