# integration - Normalize function in fenics

I have a function in fenics which is defined on product function space (for real and imaginary parts). Now I want to compute the integral of this function over the domain. I have no glue how this should work. And I am not able to find something in the documentation. I think the documentation has changed this week since non of the google links is working anymore. The Function space is defined as follows:

FuncSpace = FiniteElement( "CG" , mesh.ufl_cell() , 1 )

FuncSpace2 = FunctionSpace( mesh , MixedElement( [ FuncSpace , FuncSpace ] )

And the function is defined as:

Psi = Function( FuncSpace2 )

I am solving some partial integration problem and afterwards want to compute the integral of this function. Can anyone help me with this problem I am quite stuck?

Or can I convert the function to some python array because then I the integration would be straightforward

## Leander-

2019-11-13

So I found the answer now. First I split the result function Psi into real and complex part

next I define the abs value of the function by:

Now I have to define a measure on the used mesh:

where mesh contains a mesh defined by fenics. And last the integral is solved by: