维特比算法

# 状态转移矩阵
A = [[0.5, 0.2, 0.3],
     [0.3, 0.5, 0.2],
     [0.2, 0.3, 0.5]]
# 观测概率矩阵
B = [[0.5, 0.5],
     [0.4, 0.6],
     [0.7, 0.3]]
# 观测序列
pi = [0.2, 0.4, 0.4]

def a1():
    t = 0
    a = []
    for i in range(len(pi)):
        a.append(pi[i] * B[i][t])
    return a
a = a1()
print(a)


def q(a, t):
    b = []
    for i in range(len(A)):
        c = []
        for j in range(len(A)):
            c.append(A[j][i] * a[j])
        b.append(max(c)*B[i][t])
    print(b)
    return b


d = q(a, 1)
d = q(d, 0)