N = 100;
k = zeros(1,N);
rel = zeros(1,N);
for i = 1:N
k(i) = i*1;
seti.k = k(i);
seti = setData(seti);
qROI = seti.qROIexact;
uIncROI = seti.dSInc.*seti.incField(:,1);
V = @(x) seti.k^2.*helmholtz2Dr2r(x, seti);
QU = @(x) qROI .* x;
uBorn1 = V(QU(uIncROI));
uScattROI1 = solveLippmannSchwinger(@(x) V(QU(x)), V(QU(uIncROI)), seti);
rel(i) = norm(uBorn1-uScattROI1)/norm(uScattROI1);
end
figure(1); h = plot(k,rel);
set(gca,'FontSize',20); set(h,'LineWidth',2); axis square; print(1,'-depsc','guideBornk.eps');