主要是轉(zhuǎn)載自:
https://www.cnblogs.com/pinard/p/7001397.html

我自己加了些注釋以及修復了一個在python2.7下面運行的bug

1） 評估觀察序列概率。 給定模型λ=(A,B,π)和觀測序列O 計算P(O|λ)2）模型參數(shù)學習問題。 觀測序列O 輸出λ=(A,B,π)3）預測問題，也稱為解碼問題。 已知模型(A,B,π),觀測序列O(o1,o2,···,oT) 求令P(I|O)最大的狀態(tài)序列I=(i1,i2,···,iT)

第1個基恩問題和第3個基本問題:

# -*- coding: utf-8 -*- import sys reload(sys) sys.setdefaultencoding('utf-8') # @Author: appleyuchi # @Date: 2018-12-31 16:11:34 # @Last Modified by: appleyuchi # @Last Modified time: 2018-12-31 17:19:26import numpy as np from hmmlearn import hmm from math import log from math import e states = ["box 1", "box 2", "box3"] n_states = len(states)observations = ["red", "white"] n_observations = len(observations)start_probability = np.array([0.2, 0.4, 0.4])transition_probability = np.array([[0.5, 0.2, 0.3],[0.3, 0.5, 0.2],[0.2, 0.3, 0.5] ])emission_probability = np.array([[0.5, 0.5],[0.4, 0.6],[0.7, 0.3] ])model = hmm.MultinomialHMM(n_components=n_states) model.startprob_=start_probability#π model.transmat_=transition_probability#轉(zhuǎn)移概率A model.emissionprob_=emission_probability#摸取小球的概率Bseen = np.array([[0,1,0]]).T#這里的意思是輸入序列為(紅,白,紅)logprob, box = model.decode(seen, algorithm="viterbi") # print "observations=",observations # print "seen=",seen print"box=",boxprint"---------------下面是隱馬爾科夫第1個基本問題-------------------" # print e # print model.score(seen) print "《統(tǒng)計學習方法》P178的HMM第1個基本問題:\nP(O|λ)=",e**model.score(seen)print"---------------下面是隱馬爾科夫第2個基本問題-------------------"print"---------------下面是隱馬爾科夫第3個基本問題-------------------" print"The ball picked:", ", ".join(map(lambda x: observations[x], seen[0])) print"《統(tǒng)計學習方法》P187的HMM第3個基本問題", ", ".join(map(lambda x: states[x], box))

第二個基本問題:

# -*- coding: utf-8 -*- import sys reload(sys) sys.setdefaultencoding('utf-8')import numpy as np from hmmlearn import hmmstates = ["box 1", "box 2", "box3"] n_states = len(states)observations = ["red", "white"] n_observations = len(observations) model2 = hmm.MultinomialHMM(n_components=n_states, n_iter=20, tol=0.01) X2 = np.array([[0,1,0,1],[0,0,0,1],[1,0,1,1]]) print"-------------------------------------------" model2.fit(X2) print "π=",model2.startprob_ print "A=",model2.transmat_ print "B=",model2.emissionprob_ print model2.score(X2) print"-------------------------------------------" model2.fit(X2) print "π=",model2.startprob_ print "A=",model2.transmat_ print "B=",model2.emissionprob_ print model2.score(X2) print"-------------------------------------------" model2.fit(X2) print "π=",model2.startprob_ print "A=",model2.transmat_ print "B=",model2.emissionprob_ print model2.score(X2) 創(chuàng)作挑戰(zhàn)賽新人創(chuàng)作獎勵來咯，堅持創(chuàng)作打卡瓜分現(xiàn)金大獎

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