The error message says it all :-) Using `return ((0 <= x < L) and (0 <= y < W)) ` should fix your problem.
Best, Bas On Mon, 31 Oct 2016 at 14:29 Camilla Espedal < mailto:Camilla Espedal <camilla.espe...@ntnu.no> > wrote: a, pre, code, a:link, body { word-wrap: break-word !important; } Hi again, Thanks, I will try to write it more clearly. So the script I use to make the system is: L = 100 W = 40 a = 1 t = 1 def make_system(W,L,a,t): # Make the lattices # We define two lattices (up and down) with two sublattices A and B lat_up = kwant.lattice.general([(a,a),(a,-a)],[(0,0),(a,0)], name='up') A_up, B_up = lat_up.sublattices lat_down = kwant.lattice.general([(a,a),(a,-a)],[(0,0),(a,0)], name='down') A_down, B_down = lat_down.sublattices # Define the shape of the scattering region. Must return true where there are sites. def shape_sr(pos): x, y = pos return ((0 < x < L) and (0 < y < W)) sys = kwant.Builder() sys[lat_up.shape(shape_sr, (1,1))] = 2 sys[lat_down.shape(shape_sr, (1,1))] = 2 sys[A_up(1,1), A_down(2,1)] = 2 return sys The error message I get is: KeyError: Site(kwant.lattice.Monoatomic([[1,1], [1,-1]], [0,0]. 'up0'), array([1, 1])) I can not see why the spot should not be created, because it is within the bounds of shapre_sr. Thanks, Best, Camilla -----Original Message----- From: Anton Akhmerov [mailto: mailto:anton.akhme...@gmail.com ] Sent: 31. oktober 2016 12:04 To: Camilla Espedal < mailto:camilla.espe...@ntnu.no > Cc: mailto:kwant-discuss@kwant-project.org Subject: Re: [Kwant] Hopping between different lattices and families Hi Camilla, Please double-check the error message that you see. Your assumption why the code doesn't work is not right: it's possible to add a hopping from any site to any site, regardless of distance or lattices involved. My best guess is that the sites aren't present in the system yet. As a general advice, when describing a problem try to provide complete information required to reproduce this problem. A script and the error message would be usually useful. Best, Anton On Mon, Oct 31, 2016 at 6:58 AM, Camilla Espedal < mailto:camilla.espe...@ntnu.no > wrote: > Hi again, > > I tried to add > > sys[A_up(2,2), B_down(2,2)] = 2 > > This does not work, and I think it is because A_up and B_down are not > only on different sublattices, but on different lattices as well. In > the tutorial on superconductors > ( https://kwant-project.org/doc/1.0/tutorial/tutorial5#lattice-descript > ion-using-different-lattices) they define the hopping as > > sys[((lat_e(x, y), lat_h(x, y)) for x in range(Deltapos, L) > for y in range(W))] = Delta > > between the lattices but on the same spatial point. But I want to hop between > two different lattices from one point in space to another, if that makes > sense. > > Best, > Camilla > > -----Original Message----- > From: Anton Akhmerov [mailto: mailto:anton.akhme...@gmail.com ] > Sent: 31. oktober 2016 11:48 > To: Camilla Espedal < mailto:camilla.espe...@ntnu.no > > Cc: mailto:kwant-discuss@kwant-project.org > Subject: Re: [Kwant] Hopping between different lattices and families > > Hi Camilla, > > It's exactly like you would expect: syst[A_up(i, j), B_down(i, j)] = > value. See e.g. https://kwant-project.org/doc/1/tutorial/tutorial4 > > Best, > Anton > > On Mon, Oct 31, 2016 at 6:43 AM, Camilla Espedal < mailto:camilla.espe...@ntnu.no > wrote: >> Hi, >> >> >> >> To explain what I mean. I have a system where I have separated >> spin-up and spin-down into two lattices (like electron and hole in >> the example at the kwant site) so that it is would be easier to >> extract spin-resolved information (G_up/up, Gup/down etc.). In >> addition, these two lattices consists of two sublattices (A and B). >> The code is like this >> >> >> >> lat_up = >> kwant.lattice.general([(1,0),(s,c)],[(0,0),(0,1/sqrt(3))], >> name='up') >> >> A_up, B_up = lat_up.sublattices >> >> lat_down = >> kwant.lattice.general([(1,0),(s,c)],[(0,0),(0,1/sqrt(3))], >> name='down') >> >> A_down, B_down = lat_down.sublattices >> >> >> >> What I want to do now, is to add a hopping term between say A_up >> (i,j) and B_down (i.j). So a hopping term between the two different >> lattices and sublattices. How can I implement this? Or is there a >> better way to achieve what I want? >> >> >> >> Best >> >> Camilla Espedal
