def var_elimination(factor_list: List[Factor], query_variables: List[str],
ordered_list_of_hidden_variables: List[str],
evidence_list: List[Tuple[str, Sign]]):
"""
Calculate P(factor_list | evidence_list) using variable elimination, after
all of the evidence is observed
:param factor_list: List of the factors we'll use
:param query_variables: We want to find this variables' probability
:param ordered_list_of_hidden_variables: The order to sumout variables not in query_variables or evidence_list
:param evidence_list: List of variables that we know the values of
"""
for var in ordered_list_of_hidden_variables:
# find out which factors contain var, remove them from factor_list
factors_to_multiply = []
for factor in factor_list[:]:
if var in factor.variables:
factor_list.remove(factor)
factors_to_multiply.append(factor)
# multiply all the removed factors together, then sumout var
joined_factor = factors_to_multiply[0]
for i in range(1, len(factors_to_multiply)):
joined_factor = Factor.multiply(joined_factor,
factors_to_multiply[i])
joined_factor.sumout(var)
if len(joined_factor.solution_variables) > 0:
factor_list.append(joined_factor)
print('After eliminating {0}:'.format(var))
print_all_factors(factor_list)
# multiply remaining factors together
joined_factor = factor_list[0]
for i in range(1, len(factor_list)):
joined_factor = Factor.multiply(joined_factor, factor_list[i])
joined_factor.normalize()
final_factor = Factor(query_variables, [], joined_factor.table[:, -1], [],
evidence_list)
print('Solution:')
final_factor.print_representation()
final_factor.print_factor()
def inference_by_enumeration(factor_list: List[Factor],
ordered_list_of_hidden_variables: List[str]):
"""
Calculate P(factor_list | evidence_list) using inference by enumeration, after
all of the evidence is observed
This function is unused when doing inference
:param factor_list: List of the factors we'll use
:param ordered_list_of_hidden_variables: The order to sumout variables not in query_variables or evidence_list
"""
joined_factor = factor_list[0]
for i in range(1, len(factor_list)):
joined_factor = Factor.multiply(joined_factor, factor_list[i])
for var in ordered_list_of_hidden_variables:
joined_factor.sumout(var)
joined_factor.normalize()
joined_factor.print_factor()