kvect2(kx,ky,b1,b2,N1,N2)

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%%% diagonal matrices with elements (kx+Gx) si (ky+Gy); (kx,ky) are in the
%%% first Brillouin zone, (Gx,Gy) is a vector of the reciprocal lattice
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function [kGx, kGy] = kvect2(kx,ky,b1,b2,N1,N2)

N=N1*N2;
No1=(N1-1)/2; No2=(N2-1)/2;
kGx=zeros(N1,N2); kGy=zeros(N1,N2);
 for l=1:N1
    for m=1:N2
         kGx(m,l)=kx+(l-1-No1)*b1(1)+(m-1-No2)*b2(1);
         kGy(m,l)=ky+(l-1-No1)*b1(2)+(m-1-No2)*b2(2);
     end
 end
kGx=diag(reshape(kGx,1,N));	kGy=diag(reshape(kGy,1,N));
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