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Cognitoware.Mathematics.Probability.Discrete

Class ConditionalValueMap<X, Y>
X: The values whose probabilities are dependent on Y.
Y: The values which affect the probability of X.

System.Object


Summary

A discrete distribution P(X|Y) that simple maps values of X and Y to a probability value.

Constructor Summary

ConditionalValueMap()

Method Summary

BayesianInference(X, RandomDistribution<Y>)
Applies Bayes' Rule to the conditional distribution using a specific value of X.
ConditionalProbabilityOf(X, Y)
Returns the probability of a specific value result given a specific value range.
ConditionBy(Y)
Creates a probability distribution of X conditioned on a specific value of Y.
Equals(Object)
Inherited from System.Object
Finalize()
Inherited from System.Object
GetHashCode()
Inherited from System.Object
GetType()
Inherited from System.Object
LikelihoodOf(X)
Creates a likelihood function for a specific value of result.
Marginalize(DiscreteConditional<Y>)
Inherited from Cognitoware.Mathematics.Probability.Discrete.DiscreteConditional
Marginalize(RandomDistribution<Y>)
Creates a probability distribution of X given a random distribution across Y.
MemberwiseClone()
Inherited from System.Object
Normalize()
Normalizes the distribution so that for each specific value of Y, the sum of probabilities over X sums to one.
SampleLikelihood(X, Double)
Selects the random value of Y that maps to the parameter values.
Set(X, Y, Double)
Maps values of X and Y to a probability value.
ToString()
Inherited from System.Object

Details

A discrete distribution P(X|Y) that simple maps values of X and Y to a probability value. The user is responsible for making sure the distribution is normalized.

Constructor Details

public ConditionalValueMap()

Method Details

public override RandomDistribution<Y> BayesianInference(X data, RandomDistribution<Y> belief)
Applies Bayes' Rule to the conditional distribution using a specific value of X.

Parameters:

data - The observed value of X.
belief - The prior belief of Y.

Returns:

The probability distribution of Y conditioned on the prior value and the observed data.

public override Double ConditionalProbabilityOf(X x, Y y)
Returns the probability of a specific value result given a specific value range. Simply looks up the specified values in a dictionary. Zero is returned if the values do not exist. Implements the abstract declaration in RandomConditional.

Parameters:

x - The value whose probability is being calculated.
y - The value that affects the probability of result.

Returns:

The conditional probability of result given range.

public override RandomDistribution<X> ConditionBy(Y y)
Creates a probability distribution of X given a known y. A new distribution value map is creating by iterating over all values of X that are mapped to y. If no condition is defined for y, then an exception is thrown.

Parameters:

y - The value of Y over which the conditional distribution.

Returns:

The probability of X given the specific value of Y.

public override RandomDistribution<Y> LikelihoodOf(X x)
Creates a likelihood function for a specific value of result. Iterates over all mapped values to build a new DistributionValueMap.

Parameters:

x - A conditional value in X.

Returns:

The likelihood of observing values in Y give the value of result.

public override RandomDistribution<X> Marginalize(RandomDistribution<Y> y)
Creates a probability distribution of X given a random distribution across Y. The probability of a value of X in this distribution is equal to the average conditional probability of X given Y (defined by this distribution) weighted by the probability of each corresponding value Y in the parameter distribution. Iterates over all mapped values to build a new DistributionValueMap.

Parameters:

y - The distribuiton across Y that is used to weight the probability distributions of X.

Returns:

The expectation of X given the probable values of Y.

public void Normalize()
Normalizes the distribution so that for each specific value of Y, the sum of probabilities over X sums to one.

public Y SampleLikelihood(X x, Double p)
Selects the random value of Y that maps to the parameter values.

Parameters:

x - A value in X.
p - A likelihood used to select a value of Y.

public void Set(X x, Y y, Double p)
Maps values of X and Y to a probability value.

Parameters:

x - The value whose probability is being calculated.
y - The value that affects the probability of result.
p - The probability of result given range.


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