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Diffstat (limited to 'beliefs/factors/cpd.py')
-rw-r--r-- | beliefs/factors/cpd.py | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/beliefs/factors/cpd.py b/beliefs/factors/cpd.py new file mode 100644 index 0000000..a286aaa --- /dev/null +++ b/beliefs/factors/cpd.py @@ -0,0 +1,45 @@ +import numpy as np + + +class TabularCPD: + """ + Defines the conditional probability table for a discrete variable + whose parents are also discrete. + + TODO: have this inherit from DiscreteFactor implementing explicit factor methods + """ + def __init__(self, variable, variable_card, + parents=[], parents_card=[], values=[]): + """ + Args: + variable: int or string + variable_card: int + parents: optional, list of int and/or strings + parents_card: optional, list of int + values: optional, 2d list or array + """ + self.variable = variable + self.parents = parents + self.variables = [variable] + parents + self.cardinality = [variable_card] + parents_card + self._values = np.array(values) + + @property + def values(self): + return self._values + + def get_values(self): + """ + Returns the tabular cpd form of the values. + """ + if len(self.cardinality) == 1: + return self.values.reshape(1, np.prod(self.cardinality)) + else: + return self.values.reshape(self.cardinality[0], np.prod(self.cardinality[1:])) + + def copy(self): + return self.__class__(self.variable, + self.cardinality[0], + self.parents, + self.cardinality[1:], + self._values) |