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object --+
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AbstractTrainer
Provide generic functionality needed in all trainers.
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x.__init__(...) initializes x; see x.__class__.__doc__ for signature
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Calculate the log likelihood of the training seqs. Arguments: o probabilities -- A list of the probabilities of each training sequence under the current parameters, calculated using the forward algorithm. |
Get a maximum likelihood estimation of transition and emmission.
Arguments:
o transition_counts -- A dictionary with the total number of counts
of transitions between two states.
o emissions_counts -- A dictionary with the total number of counts
of emmissions of a particular emission letter by a state letter.
This then returns the maximum likelihood estimators for the
transitions and emissions, estimated by formulas 3.18 in
Durbin et al:
a_{kl} = A_{kl} / sum(A_{kl'})
e_{k}(b) = E_{k}(b) / sum(E_{k}(b'))
Returns:
Transition and emission dictionaries containing the maximum
likelihood estimators.
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Calculate the maximum likelihood estimator. This can calculate maximum likelihoods for both transitions and emissions. Arguments: o counts -- A dictionary of the counts for each item. See estimate_params for a description of the formula used for calculation. |
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