当我尝试使用 pgmpy 实现 MarkovModel 时,有没有办法修复 KeyError?
When I try to implement MarkovModel using pgmpy, is there a way to fix KeyError?
我正在尝试实现马尔可夫随机场。其中,我想获取一个phi(A|B = 0, C = 1)
的值。但是,使用证据选项时,会出现 KeyError: 'B'
。我不知道为什么会这样。
下面是代码。
from pgmpy.inference import VariableElimination
import numpy as np
pf_value = model.get_partition_function()
infer = VariableElimination(model)
AIB0C1_dist = infer.query(['A'], evidence={'B':0, 'C':1}) # phi(A|B = 0, C = 1)
print('phi(A|B = 0, C = 1)')
print(AIB0C1_dist)
P_AIB0C1 = AIB0C1_dist.values/np.sum(AIB0C1_dist.values)
for val in P_AIB0C1:
print(val, '\n')
错误原因如下。
KeyError Traceback (most recent call last)
<ipython-input-22-1c3cb220fae0> in <module>
20 print(val, '\n')
21
---> 22 AIB0C1_dist = infer.query(['A'],evidence={'B':0, 'C':1}) # phi(A|B = 0, C = 1)
23 print('phi(A|B = 0, C = 1)')
24 print(AIB0C1_dist)
~\anaconda3\lib\site-packages\pgmpy\inference\ExactInference.py in query(self, variables, evidence, elimination_order, joint, show_progress)
254 )
255
--> 256 return self._variable_elimination(
257 variables=variables,
258 operation="marginalize",
~\anaconda3\lib\site-packages\pgmpy\inference\ExactInference.py in _variable_elimination(self, variables, operation, evidence, elimination_order, joint, show_progress)
157 eliminated_variables = set()
158 # Get working factors and elimination order
--> 159 working_factors = self._get_working_factors(evidence)
160 elimination_order = self._get_elimination_order(
161 variables, evidence, elimination_order, show_progress=show_progress
~\anaconda3\lib\site-packages\pgmpy\inference\ExactInference.py in _get_working_factors(self, evidence)
43 for evidence_var in evidence:
44 for factor, origin in working_factors[evidence_var]:
---> 45 factor_reduced = factor.reduce(
46 [(evidence_var, evidence[evidence_var])], inplace=False
47 )
~\anaconda3\lib\site-packages\pgmpy\factors\discrete\DiscreteFactor.py in reduce(self, values, inplace)
453 phi.variables = [phi.variables[index] for index in var_index_to_keep]
454 phi.cardinality = phi.cardinality[var_index_to_keep]
--> 455 phi.del_state_names([var for var, _ in values])
456
457 phi.values = phi.values[tuple(slice_)]
~\anaconda3\lib\site-packages\pgmpy\utils\state_name.py in del_state_names(self, var_list)
92 """
93 for var in var_list:
---> 94 del self.state_names[var]
95 del self.name_to_no[var]
96 del self.no_to_name[var]
KeyError: 'B'
有没有办法修复 KeyError?
改用self.state_names.get(var,"")
。
我已经添加了 state_names。 'B' 已定义为键。
from pgmpy.models import MarkovModel
from pgmpy.factors.discrete import DiscreteFactor
model = MarkovModel([('A', 'B'), ('B', 'C'), ('C', 'D'), ('D', 'A')])
factor1 = DiscreteFactor(['A', 'B'], [2, 2], [30, 5, 1, 10], state_names={'A': [0, 1], 'B': [0, 1]})
factor2 = DiscreteFactor(['B', 'C'], [2, 2], [100, 1, 1, 100], state_names={'A': [0, 1], 'C': [0, 1]})
factor3 = DiscreteFactor(['C', 'D'], [2, 2], [1, 100, 100, 1], state_names={'C': [0, 1], 'D': [0, 1]})
factor4 = DiscreteFactor(['D', 'A'], [2, 2], [100, 1, 1, 100], state_names={'D': [0, 1], 'A': [0, 1]})
model.add_factors(factor1, factor2, factor3, factor4)
有证据的代码还是有问题
我正在尝试实现马尔可夫随机场。其中,我想获取一个phi(A|B = 0, C = 1)
的值。但是,使用证据选项时,会出现 KeyError: 'B'
。我不知道为什么会这样。
下面是代码。
from pgmpy.inference import VariableElimination
import numpy as np
pf_value = model.get_partition_function()
infer = VariableElimination(model)
AIB0C1_dist = infer.query(['A'], evidence={'B':0, 'C':1}) # phi(A|B = 0, C = 1)
print('phi(A|B = 0, C = 1)')
print(AIB0C1_dist)
P_AIB0C1 = AIB0C1_dist.values/np.sum(AIB0C1_dist.values)
for val in P_AIB0C1:
print(val, '\n')
错误原因如下。
KeyError Traceback (most recent call last)
<ipython-input-22-1c3cb220fae0> in <module>
20 print(val, '\n')
21
---> 22 AIB0C1_dist = infer.query(['A'],evidence={'B':0, 'C':1}) # phi(A|B = 0, C = 1)
23 print('phi(A|B = 0, C = 1)')
24 print(AIB0C1_dist)
~\anaconda3\lib\site-packages\pgmpy\inference\ExactInference.py in query(self, variables, evidence, elimination_order, joint, show_progress)
254 )
255
--> 256 return self._variable_elimination(
257 variables=variables,
258 operation="marginalize",
~\anaconda3\lib\site-packages\pgmpy\inference\ExactInference.py in _variable_elimination(self, variables, operation, evidence, elimination_order, joint, show_progress)
157 eliminated_variables = set()
158 # Get working factors and elimination order
--> 159 working_factors = self._get_working_factors(evidence)
160 elimination_order = self._get_elimination_order(
161 variables, evidence, elimination_order, show_progress=show_progress
~\anaconda3\lib\site-packages\pgmpy\inference\ExactInference.py in _get_working_factors(self, evidence)
43 for evidence_var in evidence:
44 for factor, origin in working_factors[evidence_var]:
---> 45 factor_reduced = factor.reduce(
46 [(evidence_var, evidence[evidence_var])], inplace=False
47 )
~\anaconda3\lib\site-packages\pgmpy\factors\discrete\DiscreteFactor.py in reduce(self, values, inplace)
453 phi.variables = [phi.variables[index] for index in var_index_to_keep]
454 phi.cardinality = phi.cardinality[var_index_to_keep]
--> 455 phi.del_state_names([var for var, _ in values])
456
457 phi.values = phi.values[tuple(slice_)]
~\anaconda3\lib\site-packages\pgmpy\utils\state_name.py in del_state_names(self, var_list)
92 """
93 for var in var_list:
---> 94 del self.state_names[var]
95 del self.name_to_no[var]
96 del self.no_to_name[var]
KeyError: 'B'
有没有办法修复 KeyError?
改用self.state_names.get(var,"")
。
我已经添加了 state_names。 'B' 已定义为键。
from pgmpy.models import MarkovModel
from pgmpy.factors.discrete import DiscreteFactor
model = MarkovModel([('A', 'B'), ('B', 'C'), ('C', 'D'), ('D', 'A')])
factor1 = DiscreteFactor(['A', 'B'], [2, 2], [30, 5, 1, 10], state_names={'A': [0, 1], 'B': [0, 1]})
factor2 = DiscreteFactor(['B', 'C'], [2, 2], [100, 1, 1, 100], state_names={'A': [0, 1], 'C': [0, 1]})
factor3 = DiscreteFactor(['C', 'D'], [2, 2], [1, 100, 100, 1], state_names={'C': [0, 1], 'D': [0, 1]})
factor4 = DiscreteFactor(['D', 'A'], [2, 2], [100, 1, 1, 100], state_names={'D': [0, 1], 'A': [0, 1]})
model.add_factors(factor1, factor2, factor3, factor4)
有证据的代码还是有问题