前向算法

A = [[0.5, 0.2, 0.3],
     [0.3, 0.5, 0.2],
     [0.2, 0.3, 0.5]]

B = [[0.5, 0.5],
     [0.4, 0.6],
     [0.7, 0.3]]

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 = 0
        for j in range(len(A)):
            c += A[j][i] * a[j]
        b.append(c*B[i][t])
    print(b)
    return b

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