我正在尝试计算序列的一步、两步转移概率矩阵,如下所示:
sample = [1,1,2,2,1,3,2,1,2,3,1,2,3,1,2,3,1,2,1,2]
import numpy as np
def onestep_transition_matrix(transitions):
n = 3 #number of states
M = [[0]*n for _ in range(n)]
for (i,j) in zip(transitions,transitions[1:]):
M[i-1][j-1] += 1
#now convert to probabilities:
for row in M:
s = sum(row)
if s > 0:
row[:] = [f/s for f in row]
return M
one_step_array = np.array(onestep_transition_matrix(sample))
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我的问题,我们如何计算两步转移矩阵。因为当我手动计算矩阵时,它如下所示:
two_step_array = array([[1/7,3/7,3/7],
[4/7,2/7,1/7],
[1/4,3/4,0]])
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然而。np.dot(one_step_array,one_step_arrary) 给了我一个不同的结果,如下所示:
array([[0.43080357, 0.23214286, 0.33705357],
[0.43622449, 0.44897959, 0.11479592],
[0.20089286, 0.59821429, 0.20089286]])
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请让我知道哪个是正确的。