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?