2d Integration over a 2d domain

Hello all,

I need you support to calculate
I = (1/V) ∬ 2πqr(µe.We+µp.Wp+µn.Wn) EL drdz

where We,n,p and µe, and El are finite element functions and µn, p are real numbers

Ve Ne, Neold;
Ve Np, Npold;
Ve Nn, Nnold;
Ve We, Wp, Wn;

I tried two times with two different approaches

the first to apply int2d as below

I = int2d(Th)(2pixq(mueWe + mupWp+ munWn)((EL)));|
I = I/abs(Vapp);

and the second is to create a for loop over the mesh number of degree of freedom

for (int p=0; p<Vh.ndof; ++p)
	I = We[][p]*Ne[][p];
	I = I + Wp[][p]*Np[][p];
	I = I + Wn[][p]*Nn[][p];
	I = I * EL[][p];
	I = I * 2*pi*q;
	I = I /(abs(Vapp));
	Is += I;
	//cout << I << endl;

and it is always return zero in the two trails