Dear kwant community:
I have encountered this error in my code. Basically I don't want to redefine
the hop in the y direction, so I use the existing function `hop`. However, the
code throw me an error which I don't know how to fix. Below is a simplest code
example, the real situation is more complex but the spirit is the same.
```
lat = kwant.lattice.square()
def make_system(r=10, t=1):
def circle(pos):
x, y = pos
return x**2+y**2<r**2
syst = kwant.Builder()
def onsite(site):
return 0
syst[lat.shape(circle, (0, 0))] = onsite
def hop(site1, site2, some_param):
# some complex calculations not shown.
return t
def modified_hop(alpha, hop):
# I don't want to define a hopy function, just use the exist hop
return lambda *a, **kw: alpha*hop(*a, **kw)
alpha = 0.5
syst[kwant.builder.HoppingKind(lat.prim_vecs[0], lat, lat)] = hop
syst[kwant.builder.HoppingKind(lat.prim_vecs[1], lat, lat)] =
modified_hop(alpha, hop) # alpha*hop would be very nice, but it won't work!
syst.eradicate_dangling()
return syst
syst = make_system()
fsyst = syst.finalized()
H = fsyst.hamiltonian_submatrix(params=dict(some_param=1))
```
Best,
Wilson
