2404.sagews

import pprint
import itertools
from collections import namedtuple

We have a car that has as usual a fuel warning light. We know that our light is ON if the car is in reserve, but can be ON too if the car is traveling up or if the acceleration is high. Sometime the sensor can be broken or the light burned and the light is always OFF.

vr = namedtuple('VR', 'v r')
sar = namedtuple('SAR', 's a r')
VR = {vr(0,0):20, vr(0,1):1, vr(1,0):1, vr(1,1):20}
SAR = {sar(0,0,0):12, sar(0,0,1):12, sar(0,1,0):5, sar(0,1,1):2, sar(1,0,0):2, sar(1,0,1):2, sar(1,1,0):2, sar(1,1,1):5}

sarv = namedtuple('SARV', 's a r v')
world = [sarv(*x) for x in itertools.product(*[(0,1)]*4)]

Z = sum([float(VR[vr(x.v, x.r)]*SAR[sar(x.s, x.a, x.r)]) for x in world])

Px = [(x, VR[vr(x.v, x.r)]*SAR[sar(x.s, x.a, x.r)]/Z) for x in world]

pprint.pprint(Px)

[(SARV(s=0, a=0, r=0, v=0), 0.27210884353741499), (SARV(s=0, a=0, r=0, v=1), 0.013605442176870748), (SARV(s=0, a=0, r=1, v=0), 0.013605442176870748), (SARV(s=0, a=0, r=1, v=1), 0.27210884353741499), (SARV(s=0, a=1, r=0, v=0), 0.11337868480725624), (SARV(s=0, a=1, r=0, v=1), 0.0056689342403628117), (SARV(s=0, a=1, r=1, v=0), 0.0022675736961451248), (SARV(s=0, a=1, r=1, v=1), 0.045351473922902494), (SARV(s=1, a=0, r=0, v=0), 0.045351473922902494), (SARV(s=1, a=0, r=0, v=1), 0.0022675736961451248), (SARV(s=1, a=0, r=1, v=0), 0.0022675736961451248), (SARV(s=1, a=0, r=1, v=1), 0.045351473922902494), (SARV(s=1, a=1, r=0, v=0), 0.045351473922902494), (SARV(s=1, a=1, r=0, v=1), 0.0022675736961451248), (SARV(s=1, a=1, r=1, v=0), 0.0056689342403628117), (SARV(s=1, a=1, r=1, v=1), 0.11337868480725624)]