[Wannier] WF computed on plot.F90

[Rafael Sarmiento]

Hello
I'm following the PRB.74.195118 and PRB.75.195121 to try to do similar 
things.

In order to compute the <Rm|O|0n> terms, I'm constructing the WF from 
the UNKp.s files in a similar way
than the one the code already does.

I think equation (6) on PRB.75.195121 should be:

        if(have_disentangled) then
           r_wvfn=cmplx_0
           do loop_w=1,num_wann
              do loop_b=1,num_inc
                 r_wvfn(:,loop_w)=r_wvfn(:,loop_w)+ &
u_matrix_opt(loop_b,loop_w,loop_kpt)*r_wvfn_tmp(:,loop_b)
              end do
           end do
        end if

and u_matrix_opt the u matrix used to mix the Bloch states
in order to get the MLWF,
but now I don't understand what is the u_matrix in the computation of 
the WF in the following lines on plot.F90:

wann_func(nxx,nyy,nzz,loop_w)=wann_func(nxx,nyy,nzz,loop_w)+ &
u_matrix(loop_b,wannier_plot_list(loop_w),loop_kpt)*r_wvfn(npoint,loop_b)*catmp

Could you please tell me what are the u_matrix and u_matrix_opt?
thanks in advance
Rafael