def __init__(self, h, loc, sign=True):
# Initiates a Walker object.
self.loc = loc
if sign:
self.signed_num = 1
else:
self.signed_num = -1
self.diag = load_data.get_entry(h, self.loc.occup, self.loc.occup)
# For test only.
if global_var.test_print_flag:
print "Created walker at ",
print self.loc.occup
def die(self, h):
# The death/cloning process of one parent on this walker site.
prob = global_var.tau * (
load_data.get_entry(h, self.loc.occup, self.loc.occup) - h.ref_energy - global_var.shift
)
rand_val = random.random()
# For test only.
if global_var.test_print_flag:
print "Start of dying step"
print "Probability is ",
print prob
print "Random number is",
print rand_val
if prob < 0:
# Cloning.
# For test only.
if global_var.test_print_flag:
print "In fact it is cloning"
prob = -prob
clone_num = int(prob)
if rand_val < prob - clone_num:
# Another cloning is successful.
# For test only.
if global_var.test_print_flag:
print "One walker is cloned."
clone_num += 1
if self.signed_num > 0:
self.signed_num += clone_num
else:
self.signed_num -= clone_num
else:
# Death.
if rand_val < prob:
# Dead.
# For test only.
if global_var.test_print_flag:
print "One walker dies."
if self.signed_num > 0:
self.signed_num -= 1
else:
self.signed_num += 1
else:
# For test only.
if global_var.test_print_flag:
print "No one dies."
# For test only.
if global_var.test_print_flag:
print "Number of living walkers on this site:",
print self.signed_num
print "End of dying step"
print ""
def spawn(self, h):
# Spawning of one parent on this walker site.
# Returns a Walker object named child.
select_prob, spawn_to = self.loc.excite(h.basis_list, "r")
child = None
child_num = 0
# For test only.
if global_var.test_print_flag:
print "Start of spawning step"
print "Attempt to spawn at",
print spawn_to.occup
# Gets the probability of spawning.
# It may be larger than unity, which may imply multiple spawning.
prob = global_var.tau * load_data.get_entry(h, self.loc.occup, spawn_to.occup) / select_prob
if prob < 0:
# Children have the same sign as their parent.
child_sign = self.signed_num > 0
prob = -prob
else:
# Children have the opposite sign as their parent.
child_sign = self.signed_num < 0
child_num = int(prob)
if child_num > 0:
# Spawns child_num children successfully.
child = Walker(h, spawn_to)
child.signed_num = child_num
if not child_sign:
child.signed_num = -child.signed_num
rand_val = random.random()
# For test only.
if global_var.test_print_flag:
for i in range(child_num):
print "Probability is ",
print prob - i
print "Spawn successfully"
print "Probability is ",
print prob - child_num
print "Random number is",
print rand_val
if rand_val < prob - child_num:
# Another spawning is successful.
# For test only.
if global_var.test_print_flag:
print "Spawn successfully"
if child_num == 0:
child = Walker(h, spawn_to, child_sign)
elif child_sign:
child.signed_num += 1
else:
child.signed_num -= 1
else:
# Spawning is unsuccessful.
# For test only.
if global_var.test_print_flag:
print "Spawn unsuccessfully"
# For test only.
if global_var.test_print_flag:
if child != None:
print "Number of living walkers on this site:",
print child.signed_num
print "End of spawning step"
print ""
return child