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我已经为每个节点设置了3个状态的贝叶斯网络,并且可以从它读取特定状态的logp(如代码中所示)。pymc3多类贝叶斯网络 - 如何抽样?
接下来我想从中抽样。在下面的代码中,抽样运行,但我没有看到输出中三个状态的分布;相反,我看到一个均值和方差就好像它们是连续的节点。我如何获得三种状态的后验?
进口numpy的为NP 进口pymc3作为MC 进口pylab,数学
模型= mc.Model() 与模型:
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)