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Python library for Hidden Markov Models

Project description

==================================
Python Hidden Markov Model Library
==================================

This library is a pure Python implementation of Hidden
Markov Models (HMMs). The project structure is quite
simple::

Help on module Markov:

NAME
Markov - Library to implement hidden Markov Models

FILE
Markov.py

CLASSES
__builtin__.object
BayesianModel
HMM
Distribution
PoissonDistribution
Probability

class BayesianModel(__builtin__.object)
| Represents a Bayesian probability model
|
| Methods defined here:
|
| MaximumLikelihoodOutcome(self, PriorProbs=None)
| Returns the maximum likelihood outcome given PriorProbs
|
| MaximumLikelihoodState(self, Observations=None)
| Returns the maximum likelihood of the internal state. If Observations
| is None, defaults to the maximum likelihood of the Prior
|
| Outcomes(self)
| Returns an iterator over the possible outcomes
|
| PriorProbs(self, Observations, PriorDist=None)
| Returns a Distribution representing the probabilities of the prior
| states, given a probability Distribution of Observations
|
| States(self)
| Returns an iterator over the possible states
|
| __call__(self, PriorProbs=None)
| Returns a Distribution representing the probabilities of the outcomes
| given a particular distribution of the priors, which defaults to
| self.Prior
|
| __iadd__(self, Model2)
| Updates the BayesianModel with the data in another BayesianModel
|
| __init__(self, Prior, Conditionals)
| Prior is a Distribution. Conditionals is a dictionary mapping
| each state in Prior to a Distribution
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)

class Distribution(__builtin__.object)
| Represents a probability distribution over a set of categories
|
| Methods defined here:
|
| MaximumLikelihoodState(self)
| Returns the state with the greatest likelihood
|
| Sample(self)
| Picks a random sample from the distribution
|
| States(self)
| Yields the Distribution's states
|
| Update(self, categories)
| Updates each category in the probability distiribution, according to
| a dictionary of numerator and denominator values
|
| __call__(self, item)
| Gives the probability of item
|
| __iadd__(self, Dist2)
| Updates the Distribution given another Distribution with the same states
|
| __init__(self, categories, k=0)
| The distribution may be initialised from a list of categories or a
| dictionary of category frequencies. In the latter case, Laplacian
| smoothing may be used
|
| __mul__(self, scalar)
| Returns the probability of each item, multiplied by a scalar
|
| copy(self)
| Returns a copy of the Distribution
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)

class HMM(BayesianModel)
| Represents a Hidden Markov Model
|
| Method resolution order:
| HMM
| BayesianModel
| __builtin__.object
|
| Methods defined here:
|
| Analyse(self, Sequence, MaximumLikelihood=False)
| Yields the an estimate of the internal states that generated a Sequence
| of observed values, either as the Maximum Likelihood state
| (Maximumlikelihood=True) or as a Distribution (MaximumLikelihood=False)
|
| MaximumLikelihoodState(self, Observations=None)
| Returns the maximum likelihood of the internal state. If Observations
| is None, defaults to the maximum likelihood of the the Current state, or
| the Prior if self.Current is None
|
| Outcomes(self)
|
| Predict(self)
| Returns a Distribution representing the probabilities of the next
| state given the current state
|
| PriorProbs(self, Observations)
| Returns a Distribution the prior probabilities of the HMM's states
| given a Distribution of Observations
|
| Train(self, Sequence)
| Trains the HMM from a sequence of observations
|
| Update(self, Observations)
| Updates the Prior probabilities, TransitionProbs
| and Conditionals given Observations
|
| __call__(self, PriorProbs=None)
| Returns a Distribution of outcomes given PriorProbs, which defaults
| to self.Current if it is set, or self.Prior otherwise
|
| __init__(self, states, outcomes)
| states is a list or dictionary of states, outcomes is a dictionary
| mapping each state in states to a Distribution of the output states
|
| ----------------------------------------------------------------------
| Methods inherited from BayesianModel:
|
| MaximumLikelihoodOutcome(self, PriorProbs=None)
| Returns the maximum likelihood outcome given PriorProbs
|
| States(self)
| Returns an iterator over the possible states
|
| __iadd__(self, Model2)
| Updates the BayesianModel with the data in another BayesianModel
|
| ----------------------------------------------------------------------
| Data descriptors inherited from BayesianModel:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)

class PoissonDistribution(Distribution)
| Represents a Poisson distribution
|
| Method resolution order:
| PoissonDistribution
| Distribution
| __builtin__.object
|
| Methods defined here:
|
| MaximumLikelihoodState(self)
|
| Mean(self)
| Returns the Mean of the PoissonDistribution
|
| Sample(self)
| Returns a random sample from the Poisson distribution
|
| States(self, limit=1e-07)
| Yields the PoissonDistribution's states, up to a cumulative
| probability of 1-limit
|
| Update(self, N, p=1.0)
| Updates the distribution, given a value N that has a probability of P
| of being drawn from this distribution
|
| __call__(self, N)
| Returns the probability of N
|
| __init__(self, mean)
| Initialises the distribution with a given mean
|
| copy(self)
| Returns a copy of the PoissonDistribution
|
| ----------------------------------------------------------------------
| Methods inherited from Distribution:
|
| __iadd__(self, Dist2)
| Updates the Distribution given another Distribution with the same states
|
| __mul__(self, scalar)
| Returns the probability of each item, multiplied by a scalar
|
| ----------------------------------------------------------------------
| Data descriptors inherited from Distribution:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)

class Probability(__builtin__.object)
| Represents a probability as a callable object
|
| Methods defined here:
|
| Update(self, deltaN, deltaD)
| Updates the probability during Bayesian learning
|
| __call__(self)
| Returns the value of the probability
|
| __iadd__(self, Prob2)
| Updates the probability given another Probability object
|
| __init__(self, n, d)
| Initialises the probability from a numerator and a denominator
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| __dict__
| dictionary for instance variables (if defined)
|
| __weakref__
| list of weak references to the object (if defined)

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