###########################################################
#                                                         #
#    Exercise 4.14:                                       #
#                                                         #
#    Construct an ROBDD for a given k-out-of-n            #
#    system and evaluate its reliability                  #
#                                                         #
###########################################################

from c_robdd import ROBDDSystem
from c_threshold import ROBDDThreshold

import matplotlib.pyplot as plt
import numpy as np

save_plots = True

# Component reliabilities            
p = 0.5

k = 13
n = 25

# Number of plot points
points = 100

# Component weights
a = []
for _ in range(n):
    a.append(1)

sys = ROBDDSystem(ROBDDThreshold(a, n, k))

result = sys.calculateReliability0(p)
sys.printSystem()

print("")
print("System unreliability = ", result[0])
print("System reliability = ", result[1])

pp = np.linspace(0.0, 1.0, points)
uu = np.zeros(points)
hh = np.zeros(points)

for i in range(points):
    result = sys.calculateReliability0(pp[i])
    uu[i] = result[0]
    hh[i] = result[1]
    
fig = plt.figure(figsize = (7, 4))
plt.plot(pp, uu, label='u(p)')
plt.plot(pp, hh, label='h(p)')
plt.xlabel('p')
# plt.ylabel('h and u')
plt.title("Reliability / unreliability vs. p")
plt.legend()
if save_plots:
    plt.savefig("k_out_of_n/relplot_" + str(k) + "_" + str(n) + ".pdf")
plt.show()