def compute(n):
spins = [2 for i in range(n)]
sc = spinchain.Spin_Chain(spins) # create the chain
sc.clean()
sc = spinchain.Spin_Chain(spins) # create the chain
def fj(i, j):
if 0.9 < abs(i - j) < 1.1: return 1.0
return 0.0
sc.set_exchange(fj) # set exchange couplings
#sc.set_fields(lambda x: [0.2,0.2,0.2]) # set exchange couplings
sc.maxm = 10
sc.nsweeps = 2
sc.get_gs()
i = 0
j = 1
t0 = time.time()
sc.fit_td = True
# (x,y) = sc.evolution(nt=100,dt=0.03,name="ZZ",i=i,j=j)
(x2, y2) = sc.get_dynamical_correlator(es=es, use_kpm=False, dt=0.1)
t1 = time.time()
print("Time", t1 - t0)
return t1 - t0
# Add the root path of the dmrgpy library
import os
import sys
sys.path.append(os.getcwd() + '/../../src')
import numpy as np
import spinchain
n = 20
spins = [2 for i in range(n)] # spin 1/2 heisenberg chain
sc = spinchain.Spin_Chain(spins) # create the spin chain
# dimerized coupling
def fj(i, j):
if abs(i - j) == 1:
ij = (i + j) % 4
dj = -0.2
if ij == 1: return 1.0 + dj
else: return 1.0 - dj
return 0.0
sc.set_exchange(fj) # set those exchange couplings
sc.kpmmaxm = 10 # KPM max m
fo = open("DCF.OUT", "w") # dynamical correlation function
for i in range(n): # loop over sites
(xs, ys) = sc.get_spismj(n=1000, mode="DMRG", i=i, j=i)
print("Doing", i)
for (x, y) in zip(xs, ys):
fo.write(str(i) + " ")
fo.write(str(x) + " ")