Dear Rongyang,

Thank you for your help and sugggestions. I will pay attention to the details when I use ALPS and try to use ALPS MPS library to do DMRG simulation. Though the parameter works, I still have problems. i) The ground state energy is E0= -11.1895. But I have checked it by matlab and quspin using ED method, the results calculated by the two softwares are the same E0=-10.0499. Then I asked my friend to calculate the same model with the same parameters by itensor and he also got E0=-10.0499. I suspect that there is still a problem exist in my XML files. ii) I try to use ALPS MPS. And I will read the paper about ALPS MPS for more details later.When I use open chain lattice, it can run. But when I use 2 band sublattice open chain lattice, it shows -------------------------------------------- Running task 1.
This binary contains symmetries: nu1
MAQUIS repo r4143
Temporary storage is disabled
Restoring state.
Will start again at site -1 in sweep 30
MPS initialization has finished...
Measurements.
Measuring n
Energy: 1
This task took 0.313551 seconds.
Finished with everything. -------------------------------------------- Why? iii) I want to write the tunneling rate t as a function of the position. ---------------------------------------------- import pyalps
import numpy as np

parms = [ {
       #'LATTICE' : "2 band sublattice open chain lattice",
       'LATTICE' : "open chain lattice",
       'LATTICE_LIBRARY': './lattices.xml',
       'MODEL' : "sublattice boson Hubbard",
       'MODEL_LIBRARY': './models.xml',
       'CONSERVED_QUANTUMNUMBERS' : 'N',
       'T' : 0,
       't0' : 3-2*np.cos(x*np.pi+np.pi),
       #'t1' : 1,
       'SWEEPS' : 30,
       'MAXSTATES' : 300,
       'init_state' : "thin" ,
       'NUMBER_EIGENVALUES' : 1,
       'L' : 4,
       'Nmax' : 1,
       'N_total' : 2,
       'MEASURE_LOCAL[n]' : 'n'
      } ]
input_file = pyalps.writeInputFiles('ssh',parms)
res = pyalps.runApplication('mps_optim',input_file,writexml=True) --------------------------------------------------- Then I got the error -------------------------------------------- Traceback (most recent call last):
File "./ssh.py", line 12, in <module>
    't0' : 3-2*np.cos(x*np.pi+np.pi),
NameError: name 'x' is not defined --------------------------------------------- So how can I define the parameter when it is changed by site position?