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我已經爲每個節點設置了3個狀態的貝葉斯網絡,並且可以從它讀取特定狀態的logp(如代碼中所示)。pymc3多類貝葉斯網絡 - 如何抽樣?
接下來我想從中抽樣。在下面的代碼中,抽樣運行,但我沒有看到輸出中三個狀態的分佈;相反,我看到一個均值和方差就好像它們是連續的節點。我如何獲得三種狀態的後驗?
進口numpy的爲NP 進口pymc3作爲MC 進口pylab,數學
模型= mc.Model() 與模型:
rain = mc.Categorical('rain', p = np.array([0.5, 0. ,0.5]))
sprinkler = mc.Categorical('sprinkler', p=np.array([0.33,0.33,0.34]))
CPT = mc.math.constant(np.array([ [ [.1,.2,.7], [.2,.2,.6], [.3,.3,.4] ],\
[ [.8,.1,.1], [.3,.4,.3], [.1,.1,.8] ],\
[ [.6,.2,.2], [.4,.4,.2], [.2,.2,.6] ] ]))
p_wetgrass = CPT[rain, sprinkler]
wetgrass = mc.Categorical('wetgrass', p_wetgrass)
#brute force search (not working)
for val_rain in range(0,3):
for val_sprinkler in range(0,3):
for val_wetgrass in range(0,3):
lik = model.logp(rain=val_rain, sprinkler=val_sprinkler, wetgrass=val_wetgrass)
print([val_rain, val_sprinkler, val_wetgrass, lik])
#sampling (runs but don't understand output)
if 1:
niter = 10000 # 10000
tune = 5000 # 5000
print("SAMPLING:")
#trace = mc.sample(20000, step=[mc.BinaryGibbsMetropolis([rain, sprinkler])], tune=tune, random_seed=124)
trace = mc.sample(20000, tune=tune, random_seed=124)
print("trace summary")
mc.summary(trace)