Dear Paweł,
The issue lies within the `lead.substituted` part.
Until that bit is fixed, you can go ahead and define the leads' functions and
Peierl's phase functions with different names for each lead.
I have checked that the below example works, it will be easy to adapt it to
your case.
Best regards,
Pablo
```
import numpy as np
import kwant
def hopping(a, b, t, peierls):
return -t * peierls(a, b)
def hopping_lead_1(a, b, t, peierls_lead_1):
return -t * peierls_lead_1(a, b)
def hopping_lead_2(a, b, t, peierls_lead_2):
return -t * peierls_lead_2(a, b)
size = 30
def make_system(hopping):
lat = kwant.lattice.square(norbs=1)
syst = kwant.Builder()
syst[(lat(i, j) for i in range(size) for j in range(size))] = 0
syst[lat.neighbors()] = hopping
return syst
def make_lead(hopping_lead, lattice_direction=(-1, 0)):
symmetry = kwant.TranslationalSymmetry(lattice_direction)
lat = kwant.lattice.square(norbs=1)
lead = kwant.Builder(symmetry=symmetry)
lead[(lat(i, j) for j in range(size)
for i in range(abs(lattice_direction[0])))] = 0
lead[lat.neighbors()] = hopping_lead
return lead
syst = make_system(hopping)
lead_1 = make_lead(hopping_lead_1, lattice_direction=(1, 0))
lead_2 = make_lead(hopping_lead_2, lattice_direction=(-1, 0))
syst.attach_lead(lead_1)
syst.attach_lead(lead_2)
syst = syst.finalized()
gauge = kwant.physics.magnetic_gauge(syst)
def B_syst(pos):
return np.pi / 10
peierls_syst, peierls_lead_1, peierls_lead_2 = gauge(B_syst, B_syst, B_syst)
params = dict(t=1, peierls=peierls_syst,
peierls_lead_1=peierls_lead_1,
peierls_lead_2=peierls_lead_2)
smatrix = kwant.smatrix(syst, params=params, energy=1)
print(smatrix.transmission(0, 1))
```
