AssertionError：应该有来自model.start的两个边缘，来自Rainy的两个边缘，以及来自Sunny的两个边缘

Question

虽然我在HMM中制作模型时陷入问题AssertionError，但无法找出问题所在？

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
from helpers import show_model
from pomegranate import State, HiddenMarkovModel, DiscreteDistribution



model = HiddenMarkovModel(name='Example Model')

#Emission probabiliy of distributions, p(umbrella|weather)
sunny_emission = DiscreteDistribution({'yes':0.1, 'no':0.8})
sunny_state = State(sunny_emission, name='Sunny')

rainy_emission = DiscreteDistribution({'yes':0.8, 'no':0.2})
rainy_state = State(rainy_emission, name='rainy')


model.add_states(sunny_state, rainy_state)

assert rainy_emission.probability('yes') == 0.8, "The director brings his umbrella with probability 0.8 on rainy days"
print("looks good so far")

model.add_transition(model.start, sunny_state, 0.5)
model.add_transition(model.start, rainy_state, 0.5)


model.add_transition(sunny_state, sunny_state, 0.8) # 80%sunny days
model.add_transition(rainy_state, rainy_state, 0.2) # 20% rainy days


model.add_transition(rainy_state, rainy_state, 0.6)
model.add_transition(rainy_state, sunny_state, 0.4)

model.bake()


assert model.edge_count() == 6, "There should be two edges from model.start, two from Rainy, and two from Sunny"
assert model.node_count() == 4, "The states should include model.start, model.end, Rainy, and Sunny"

AssertionError：应该有来自model.start的两个边缘，来自Rainy的两个边缘，以及来自Sunny的两个边缘

Answer 1

您收到该错误的原因是，在您的代码中，隐藏状态（'SUNNY'）只有5个边，但是assert语句正在检查6个边。

**model.add_transition(rainy_state, rainy_state, 0.2) # 20% rainy days**

这是错误所在的行，这里的转换是从“多雨到多雨”，而不是“晴天到多雨”。