################################################################################
#
# TRIQS: a Toolbox for Research in Interacting Quantum Systems
#
# Copyright (C) 2011 by M. Ferrero, O. Parcollet
#
# TRIQS is free software: you can redistribute it and/or modify it under the
# terms of the GNU General Public License as published by the Free Software
# Foundation, either version 3 of the License, or (at your option) any later
# version.
#
# TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
# details.
#
# You should have received a copy of the GNU General Public License along with
# TRIQS. If not, see <http://www.gnu.org/licenses/>.
#
################################################################################

from pytriqs.lattice.tight_binding import *

# Define the Bravais Lattice : a square lattice in 2d
BL = BravaisLattice(units = [(1,0,0) , (0,1,0) ], orbital_positions= {"" :  (0,0,0)} ) 

# Prepare a nearest neighbour hopping on BL
t   = -1.00                # First neighbour Hopping
tp  =  0.0*t               # Second neighbour Hopping

# Hopping[ Displacement on the lattice] = [[t11,t12,t13....],[t21,t22,t23....],...,[....,tnn]] 
# where n=Number_Orbitals
hop = {  (1,0)  :  [[ t]],       
         (-1,0) :  [[ t]],     
         (0,1)  :  [[ t]],
         (0,-1) :  [[ t]],
         (1,1)  :  [[ tp]],
         (-1,-1):  [[ tp]],
         (1,-1) :  [[ tp]],
         (-1,1) :  [[ tp]]}

TB = TightBinding(BL, hop)

# Compute the density of states
d = dos(TB, n_kpts= 500, n_eps = 101, name = 'dos')[0]

from pytriqs.archive import HDFArchive
R = HDFArchive('dos.output.h5','w')
R['SquareLatt'] = d