def solve(chargers, n, cost, sensors, p_list):
"""
n is the number of chargers have already been considered,
enumerate every possible choise using dfs
"""
global g_C
global g_H
if n == len(chargers):
update(sensors, p_list)
return
# don't chose this charger
solve(chargers, n + 1, cost, sensors, p_list)
# chose it by every possible h
c = chargers[n]
for h in xrange(1, args['h_max'] + 1):
if power(h) + cost > g_B:
break
g_C.append(c)
g_H.append(h)
solve(chargers, n + 1, cost + power(h), sensors, p_list)
del g_C[len(g_C) - 1]
del g_H[len(g_H) - 1]
def greedy(chargers, sensors, p_list, func):
"""greedy algorithm, base on value function 'func'."""
# initialize
Budget = args["B"]
b = 0
Q = 0
H = {}
# construct matrix Z
Z = [[(c, h) for h in xrange(1, args["h_max"] + 1)] for c in chargers]
# Z'
temp_c = []
temp_h = []
while b < Budget:
max_power = 0
max_delta = 0
max_cost = 0
max_index = None
b_left = Budget - b
# find the best charger & h in matrix Z
for (i, c_h_list) in enumerate(Z):
for (j, (c, h)) in enumerate(c_h_list):
cost = power(h)
if cost <= b_left:
temp_Q = total_power(sensors, p_list, temp_c + [c], temp_h + [h])
delta = func(temp_Q - Q, cost)
if delta > max_delta:
max_power = temp_Q
max_delta = delta
max_cost = cost
max_index = (i, j)
# greedy!!!
if max_index != None:
# add max charger in Z' & remove from Z
Q = max_power
b += max_cost
(i, j) = max_index
(c, h) = Z[i][j]
temp_c.append(c)
temp_h.append(h)
del Z[i][j]
# if H[c] < h then H[c] <== h
H[c] = max(H.get(c, 0), h)
else:
break
result = (Q, H, temp_c, temp_h)
if DEBUG:
print "============================================="
print "# result of greedy part #"
print "============================================="
pprint(result)
return H
def budget_killer(H, chargers, sensors, p_list):
"""utilize the remaining budget, return (Q, chargers, h_list)"""
p_min = args["p_min"]
Budget = args["B"]
h_max = args["h_max"]
# current cost
cost = 0
temp_c = []
temp_h = []
for (c, h) in H.iteritems():
temp_c.append(c)
temp_h.append(h)
cost += power(h)
max_power = total_power(sensors, p_list, temp_c, temp_h)
while Budget - cost >= p_min:
max_charger = None
# current chosen sets
temp_c = []
temp_h = []
for (c, h) in H.iteritems():
temp_c.append(c)
temp_h.append(h)
for c in chargers:
if H.get(c, 0) < h_max:
temp_Q = total_power(sensors, p_list, temp_c + [c], temp_h + [1])
if temp_Q > max_power:
max_power = temp_Q
max_charger = c
if max_charger != None:
cost += p_min
H[max_charger] = H.get(max_charger, 0) + 1
else:
if DEBUG:
print "Warning: remaining budget can not be full filled."
break
if DEBUG:
print "============================================="
print "# utilize the remaining budget #"
print "============================================="
print "Budget : %f" % cost
result_c = []
result_h = []
for (c, h) in H.iteritems():
result_c.append(c)
result_h.append(h)
result = (max_power, result_c, result_h)
return result
def random_h():
"""generate a random h list"""
B = args['B']
cost = 0
h_list = [0 for i in xrange(args['N'])]
for i in xrange(len(h_list)):
if cost >= B:
break
if cost + power(args['h_max']) <= B:
h_list[i] = random.randint(0, args['h_max'])
else:
for h in xrange(args['h_max'] + 1):
if cost + power(h) <= B:
h_list[i] = h
cost += power(h_list[i])
random.shuffle(h_list)
return h_list
def greedy(chargers, h_list, sensors, p_list, func):
"""greedy part"""
# initialize
Budget = args['B']
b = 0
Q = 0
result_c = []
result_h = []
while b < Budget:
max_power = 0
max_delta = 0
max_cost = 0
max_index = None
b_left = Budget - b
# find the charger which can increase the total power most
for (index, (c, h)) in enumerate(zip(chargers, h_list)):
cost = power(h)
if cost <= b_left:
temp_Q = total_power(sensors, p_list, result_c + [c], result_h + [h])
delta = func(temp_Q - Q, cost)
if delta > max_delta:
max_power = temp_Q
max_delta = delta
max_cost = cost
max_index = index
# greedy the charger we found
if max_index != None:
Q = max_power
b += max_cost
result_c.append(chargers[max_index])
result_h.append(h_list[max_index])
del chargers[max_index]
del h_list[max_index]
else:
break
result = (Q, result_c, result_h)
if DEBUG:
print "============================================="
print "# result of greedy part #"
print "============================================="
pprint(result)
return result
def charger_h(c, sensors, p_list):
"""calculate h for charger c(x, y) independently"""
(ratio, h) = max([(total_power(sensors, p_list, [c], [h])/power(h), h) for h in xrange(1, args['h_max'] + 1)])
return h