Dear kwant developers,

I am currently testing the new feature of kwant 1.4 - the interface with qsymm library.

kag_lat = kwant.lattice.kagome()
kagome = kwant.Builder(kwant.TranslationalSymmetry(*kag_lat.prim_vecs))
kagome[kag_lat.shape((lambda pos: True), (0, 0))] = 0
kagome[kag_lat.neighbors(1)] = 1
kwant.plot(kagome,site_color=family_color,site_lw=0.01)
kagome = wraparound(kagome).finalized()
#dispersion_2D(kag_lat,kagome)
import kwant.qsymm
kwant.qsymm.find_builder_symmetries(kagome)

When I try to find the symmetries of the kagome lattice using the find_builder_symmetries I get the following error. Can you please help me fix this?

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-10-b70a7b7c1860> in <module>
      7 #dispersion_2D(kag_lat,kagome)
      8 import kwant.qsymm
----> 9 kwant.qsymm.find_builder_symmetries(kagome)

/anaconda3/lib/python3.6/site-packages/kwant/qsymm.py in find_builder_symmetries(builder, momenta, params, spatial_symmetries, prettify, sparse)
    449 
    450     ham = builder_to_model(builder, momenta=momenta,
--> 451                            real_space=False, params=params)
    452 
    453     # Use dense or sparse computation depending on Hamiltonian size

/anaconda3/lib/python3.6/site-packages/kwant/qsymm.py in builder_to_model(syst, momenta, real_space, params)
    153     # translation vectors.
    154     if dim == 0:
--> 155         proj = np.empty((0, len(list(syst.sites())[0].pos)))
    156     elif dim < len(list(syst.sites())[0].pos):
    157         proj, r = la.qr(np.array(periods).T, mode='economic')

TypeError: 'tuple' object is not callable

Thanks

Regards,

Srilok Srinivasan