public void TestBackwardRun2()
{
var states = new List <IState> {
new State(0, "s"), new State(1, "t")
};
var startDistribution = new [] { 0.85, 0.15 };
var tpm = new double[2][];
tpm[0] = new [] { 0.3, 0.7 };
tpm[1] = new [] { 0.1, 0.9 };
var observations = new List <IObservation>
{
new Observation(new double[] { 0 }, "A"),
new Observation(new double[] { 1 }, "B"),
new Observation(new double[] { 1 }, "B"),
new Observation(new double[] { 0 }, "A")
};
var emissions = new DiscreteDistribution[2];
emissions[0] = new DiscreteDistribution(new double[] { 0, 1 }, new[] { 0.4, 0.6 });
emissions[1] = new DiscreteDistribution(new double[] { 0, 1 }, new[] { 0.5, 0.5 });
var algo = new ForwardBackward(false);
var res = algo.RunBackward(observations, HiddenMarkovModelStateFactory.GetState(new ModelCreationParameters <DiscreteDistribution>()
{
Pi = startDistribution, TransitionProbabilityMatrix = tpm, Emissions = emissions
})); //new HiddenMarkovModelState<DiscreteDistribution>(startDistribution, tpm, emissions));
Assert.AreEqual(0.25499, res);
Assert.AreEqual(1, algo.Beta[3][0]);
Assert.AreEqual(1, algo.Beta[3][1]);
Assert.AreEqual(0.47, algo.Beta[2][0]);
Assert.AreEqual(0.49, algo.Beta[2][1]);
Assert.AreEqual(0.2561, algo.Beta[1][0]);
Assert.AreEqual(0.2487, algo.Beta[1][1]);
Assert.AreEqual(0.133143, algo.Beta[0][0]);
Assert.AreEqual(0.127281, algo.Beta[0][1]);
}
public void TestBackwardNormalizedRun2()
{
var states = new List <IState> {
new State(0, "s"), new State(1, "t")
};
var startDistribution = new [] { 0.85, 0.15 };
var tpm = new double[2][];
tpm[0] = new [] { 0.3, 0.7 };
tpm[1] = new [] { 0.1, 0.9 };
var observations = new List <IObservation>
{
new Observation(new double[] { 0 }, "A"),
new Observation(new double[] { 1 }, "B"),
new Observation(new double[] { 1 }, "B"),
new Observation(new double[] { 0 }, "A")
};
var emissions = new DiscreteDistribution[2];
emissions[0] = new DiscreteDistribution(new double[] { 0, 1 }, new[] { 0.4, 0.6 });
emissions[1] = new DiscreteDistribution(new double[] { 0, 1 }, new[] { 0.5, 0.5 });
var algo = new ForwardBackward(true);
var res = algo.RunBackward(observations, HiddenMarkovModelStateFactory.GetState(new ModelCreationParameters <DiscreteDistribution>()
{
Pi = startDistribution, TransitionProbabilityMatrix = tpm, Emissions = emissions
})); //new HiddenMarkovModelState<DiscreteDistribution>(startDistribution, tpm, emissions));
Assert.AreEqual(-1.3665309502789404, res);
Assert.AreEqual(0d, algo.Beta[3][0]);
Assert.AreEqual(0d, algo.Beta[3][1]);
Assert.AreEqual(-0.75502258427803293, algo.Beta[2][0]);
Assert.AreEqual(-0.71334988787746456, algo.Beta[2][1]);
Assert.AreEqual(-1.3621872857766575, algo.Beta[1][0]);
Assert.AreEqual(-1.3915079281727778, algo.Beta[1][1]);
Assert.AreEqual(-2.0163315403910613, algo.Beta[0][0]);
Assert.AreEqual(-2.0613580382895655, algo.Beta[0][1]);
}
public IHiddenMarkovModel <Mixture <IMultivariateDistribution> > Run(int maxIterations, double likelihoodTolerance)
{
// Initialize responce object
var forwardBackward = new ForwardBackward(Normalized);
do
{
maxIterations--;
if (!_estimatedModel.Likelihood.EqualsTo(0))
{
_currentModel = HiddenMarkovModelStateFactory.GetState(new ModelCreationParameters <Mixture <IMultivariateDistribution> > {
Pi = _estimatedPi, TransitionProbabilityMatrix = _estimatedTransitionProbabilityMatrix, Emissions = _estimatedEmissions
}); //new HiddenMarkovModelState<Mixture<IMultivariateDistribution>>(_estimatedPi, _estimatedTransitionProbabilityMatrix, _estimatedEmissions) { LogNormalized = _estimatedModel.LogNormalized };
_currentModel.Normalized = Normalized;
_currentModel.Likelihood = _estimatedModel.Likelihood;
}
// Run Forward-Backward procedure
forwardBackward.RunForward(_observations, _currentModel);
forwardBackward.RunBackward(_observations, _currentModel);
// Calculate Gamma and Xi
var @params = new MixtureSigmaEstimationParameters <Mixture <IMultivariateDistribution> >
{
Alpha = forwardBackward.Alpha,
Beta = forwardBackward.Beta,
Observations = _observations,
Model = _currentModel,
Normalized = _currentModel.Normalized,
L = _currentModel.Emission[0].Components.Length,
ObservationWeights = _observationWeights
};
_gammaEstimator = new GammaEstimator <Mixture <IMultivariateDistribution> >();
_ksiEstimator = new KsiEstimator <Mixture <IMultivariateDistribution> >();
var mixtureCoefficientsEstimator = new MixtureCoefficientsEstimator <Mixture <IMultivariateDistribution> >();
var mixtureMuEstimator = new MixtureMuEstimator <Mixture <IMultivariateDistribution> >(); // Mean
var mixtureSigmaEstimator = new MixtureSigmaEstimator <Mixture <IMultivariateDistribution> >(); // Covariance
var mixtureGammaEstimator = new MixtureGammaEstimator <Mixture <IMultivariateDistribution> >();
@params.Gamma = _gammaEstimator.Estimate(@params);
@params.GammaComponents = mixtureGammaEstimator.Estimate(@params);
EstimatePi(_gammaEstimator.Estimate(@params));
// TODO : weights for A
EstimateTransitionProbabilityMatrix(_gammaEstimator.Estimate(@params), _ksiEstimator.Estimate(@params), _observationWeights, _observations.Count);
for (var n = 0; n < _currentModel.N; n++)
{
var mixturesComponents = _currentModel.Emission[n].Coefficients.Length;
var distributions = new IMultivariateDistribution[mixturesComponents];
// Calculate coefficients for state n
// TODO : weights for W
var coefficients = mixtureCoefficientsEstimator.Estimate(@params)[n];
if (Normalized)
{
mixtureCoefficientsEstimator.Denormalize();
}
// TODO : weights Mu
@params.Mu = mixtureMuEstimator.Estimate(@params);
for (var l = 0; l < mixturesComponents; l++)
{
// TODO : weights Sigma
distributions[l] = new NormalDistribution(mixtureMuEstimator.Estimate(@params)[n, l], mixtureSigmaEstimator.Estimate(@params)[n, l]);
}
_estimatedEmissions[n] = new Mixture <IMultivariateDistribution>(coefficients, distributions);
}
_estimatedModel = HiddenMarkovModelStateFactory.GetState(new ModelCreationParameters <Mixture <IMultivariateDistribution> > {
Pi = _estimatedPi, TransitionProbabilityMatrix = _estimatedTransitionProbabilityMatrix, Emissions = _estimatedEmissions
});
_estimatedModel.Normalized = Normalized;
_estimatedModel.Likelihood = forwardBackward.RunForward(_observations, _estimatedModel);
_likelihoodDelta = Math.Abs(Math.Abs(_currentModel.Likelihood) - Math.Abs(_estimatedModel.Likelihood));
Debug.WriteLine("Iteration {3} , Current {0}, Estimate {1} Likelihood delta {2}", _currentModel.Likelihood, _estimatedModel.Likelihood, _likelihoodDelta, maxIterations);
}while (_currentModel != _estimatedModel && maxIterations > 0 && _likelihoodDelta > likelihoodTolerance);
return(_estimatedModel);
}
