# Read in initial configuration
n, bond, r = read_cnf_atoms(cnf_prefix + inp_tag)
print("{:40}{:15d} ".format('Number of particles', n))
print("{:40}{:15.6f}".format('Bond length (in sigma units)', bond))
# Initialize arrays for averaging and write column headings
m_ratio = 0.0
run_begin(calc_variables())
for blk in range(1, nblock + 1): # Loop over blocks
blk_begin()
for stp in range(nstep): # Loop over steps
r, accepted = regrow(temperature, m_max, k_max, bond, k_spring, r)
m_ratio = 1.0 if accepted else 0.0
blk_add(calc_variables())
blk_end(blk) # Output block averages
sav_tag = str(blk).zfill(
3) if blk < 1000 else 'sav' # Number configuration by block
write_cnf_atoms(cnf_prefix + sav_tag, n, bond, r) # Save configuration
run_end(calc_variables())
write_cnf_atoms(cnf_prefix + out_tag, n, bond, r) # Save configuration
conclusion()
xi = x[i]
pot_cl_old = 0.5 * xi**2 / p
pot_qu_old = 0.5 * k_spring * ((xi - x[im1])**2 + (xi - x[ip1])**2)
xi = xi + zeta * dx_max # Trial move to new position
pot_cl_new = 0.5 * xi**2 / p
pot_qu_new = 0.5 * k_spring * ((xi - x[im1])**2 + (xi - x[ip1])**2)
delta = (pot_cl_new + pot_qu_new - pot_cl_old -
pot_qu_old) / temperature
if metropolis(delta): # Accept Metropolis test
pot_cl = pot_cl + pot_cl_new - pot_cl_old # Update classical potential energy
pot_qu = pot_qu + pot_qu_new - pot_qu_old # Update quantum potential energy
x[i] = xi # Update position
moves = moves + 1 # Increment move counter
m_ratio = moves / p
if blk >= 0:
blk_add(calc_variables())
if blk >= 0:
blk_end(blk)
run_end(calc_variables())
e_qu = e_pi_sho(p, beta)
print("{:8}{:8d}{:7}{:15.6f}".format('Exact P=', p, ' energy', e_qu))
e_qu = 0.5 / math.tanh(0.5 * beta)
print("{:23}{:15.6f}".format('Exact P=infinity energy', e_qu))