Dear Kwant users, In Kwant manual there is a section entitled "Calculating spectral density with the kernel polynomial method". I find that examples in this section are all talking about finite-size systems. I wonder whether Kwant can calculate density of states of a quasi one-dimensional system that is finite along y-direction but is translationally invariant along x-direction. For a minimal test, I have run the following codes but errors occurred. #-------------------------------------------------------------------------------------- import kwant import numpy a=1 W=30 t=1 lat = kwant.lattice.square(a) syst = kwant.Builder(kwant.TranslationalSymmetry((-a, 0))) syst[(lat(0, j) for j in range(W))] = 4 * t syst[lat.neighbors()] = -t fsyst = syst.finalized() energies = numpy.linspace(-0.1,0.1, 10) spectrum = kwant.kpm.SpectralDensity(fsyst) spectrum.add_moments(10) spectrum.add_vectors(5) densities = spectrum(energies) #-------------------------------------------------------------------------------------- What's wrong in above codes? Currently, are we able to employ Kwant to calculate density of states of 3D systems being translationally invariant along one or two directions? Regards, Zhan