class TwoBAN_OS extends TwoBAN_OS0
The TwoBAN_OS class implements an Integer-Based Bayesian Network Classifier,
which is a commonly used such classifier for discrete input data. Each node is
limited to have at most 2 parents, and hence the "2" in the class name TwoBAN_OS.
The classifier is trained using a data matrix 'x' and a classification vector 'y'.
Each data vector in the matrix is classified into one of 'k' classes numbered
0, ..., k-1. Prior probabilities are calculated based on the population of
each class in the training-set. Relative posterior probabilities are computed
by multiplying these by values computed using conditional probabilities. The
classifier supports limited dependency between features/variables.
This classifier uses the standard cross-validation technique. ------------------------------------------------------------------------------
- Alphabetic
- By Inheritance
- TwoBAN_OS
- TwoBAN_OS0
- BayesClassifier
- BayesMetrics
- ClassifierInt
- Error
- Classifier
- AnyRef
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Instance Constructors
-
new
TwoBAN_OS(x: MatriI, y: VectoI, fn: Array[String], k: Int, cn: Array[String], vc: VectoI = null, thres: Double = 0.0, me: Double = me_default, PARALLELISM: Int = ...)
- x
the integer-valued data vectors stored as rows of a matrix
- y
the class vector, where y(l) = class for row l of the matrix, x(l)
- fn
the names for all features/variables
- k
the number of classes
- cn
the names for all classes
- vc
the value count (number of distinct values) for each feature
- thres
the correlation threshold between 2 features for possible parent-child relationship
- me
use m-estimates (me == 0 => regular MLE estimates)
- PARALLELISM
the level of parallelism, the number of threads to use
Value Members
-
def
aic(vc: VectoI, vcp1: VectoI, vcp2: VectoI, popX: HMatrix5[Int], k: Int, me: Float = me_default): Double
Compute the 'AIC' for the given Bayesian Network structure and data.
Compute the 'AIC' for the given Bayesian Network structure and data.
- vc
the value count
- vcp1
the value count for parent 1
- vcp2
the value count for parent 2
- popX
the population counts
- k
the number of classes
- me
the m-estimate value
- Definition Classes
- BayesMetrics
-
def
calcCMI(idx: IndexedSeq[Int], vca: Array[Int]): MatrixD
Compute the conditional mutual information matrix
Compute the conditional mutual information matrix
- Definition Classes
- BayesClassifier
-
def
calcCorrelation: MatriD
Calculate the correlation matrix for the feature vectors 'fea'.
Calculate the correlation matrix for the feature vectors 'fea'. If the correlations are too high, the independence assumption may be dubious.
- Definition Classes
- ClassifierInt
-
def
calcCorrelation2(zrg: Range, xrg: Range): MatriD
Calculate the correlation matrix for the feature vectors of Z (Level 3) and those of X (level 2).
Calculate the correlation matrix for the feature vectors of Z (Level 3) and those of X (level 2). If the correlations are too high, the independence assumption may be dubious.
- zrg
the range of Z-columns
- xrg
the range of X-columns
- Definition Classes
- ClassifierInt
-
def
classify(z: VectoI): (Int, String, Double)
Given a discrete data vector 'z', classify it returning the class number (0, ..., k-1) with the highest relative posterior probability.
Given a discrete data vector 'z', classify it returning the class number (0, ..., k-1) with the highest relative posterior probability. Return the best class, its name and its realtive probability
- z
the data vector to classify
- Definition Classes
- TwoBAN_OS0 → Classifier
-
def
classify(z: VectoD): (Int, String, Double)
Given a new continuous data vector 'z', determine which class it belongs to, by first rounding it to an integer-valued vector.
Given a new continuous data vector 'z', determine which class it belongs to, by first rounding it to an integer-valued vector. Return the best class, its name and its relative probability
- z
the vector to classify
- Definition Classes
- ClassifierInt → Classifier
-
def
cmiJoint(p_C: VectorD, p_CX: HMatrix3[Double], p_CXZ: HMatrix5[Double]): MatrixD
Compute conditional mutual information matrix given the marginal probability of C and joint probabilities of CXZ and CX, where C is the class (parent), and X & Z are features.
Compute conditional mutual information matrix given the marginal probability of C and joint probabilities of CXZ and CX, where C is the class (parent), and X & Z are features.
- p_C
the marginal probability of C
- p_CX
the joint probability of C and X
- p_CXZ
the joint probability of C, X, and Z
- Definition Classes
- BayesClassifier
- See also
en.wikipedia.org/wiki/Conditional_mutual_information
-
def
computeParent(featureOrder: VectorI = featureOrder, cmiMx: MatrixD): MatrixI
Compute the parent of each feature based on the correlation matrix.
Compute the parent of each feature based on the correlation matrix. Feature 'x_i' is only a possible candidate for parent of feature 'x_j' if 'x_i' appears before 'x_j' in 'featureOrder'.
- featureOrder
order of the features
- cmiMx
the Conditional Mutual Information matrix
- Definition Classes
- TwoBAN_OS0
-
def
computeVcp(): Unit
Compute the value counts of each parent feature based on the parent matrix.
Compute the value counts of each parent feature based on the parent matrix.
- Definition Classes
- TwoBAN_OS0
-
def
crossValidate(nx: Int = 10): Double
Test the accuracy of the classified results by cross-validation, returning the accuracy.
Test the accuracy of the classified results by cross-validation, returning the accuracy. The "test data" starts at 'testStart' and ends at 'testEnd', the rest of the data is "training data'.
- nx
the number of crosses and cross-validations (defaults to 5x).
- Definition Classes
- Classifier
-
def
crossValidateRand(nx: Int = 10): Double
Test the accuracy of the classified results by cross-validation, returning the accuracy.
Test the accuracy of the classified results by cross-validation, returning the accuracy. This version of cross-validation relies on "subtracting" frequencies from the previously stored global data to achieve efficiency.
- nx
number of crosses and cross-validations (defaults to 10x).
- Definition Classes
- Classifier
-
def
featureSelection(TOL: Double = 0.01): Unit
Perform feature selection on the classifier.
Perform feature selection on the classifier. Use backward elimination technique, that is, remove the least significant feature, in terms of cross- validation accuracy, in each round.
- TOL
tolerance indicating negligible accuracy loss when removing features
- Definition Classes
- ClassifierInt
-
final
def
flaw(method: String, message: String): Unit
- Definition Classes
- Error
-
def
frequenciesAll(): Unit
Compute frequency counts for each value in each variable from the entire data matrix.
-
def
getFeatureOrder: VectoI
Return the feature order.
Return the feature order.
- Definition Classes
- TwoBAN_OS0
-
def
getParent: MatrixI
Return the parent.
Return the parent.
- Definition Classes
- TwoBAN_OS0
-
def
learnStructure(cmiMx: MatrixD): Unit
Learn the structure of Bayes Networks2 classier model by using the 'CMI' criterion.
Learn the structure of Bayes Networks2 classier model by using the 'CMI' criterion. Limited dependencies between variables/features are also supported. Maximum number of parents for each feature is 2.
- Definition Classes
- TwoBAN_OS0
-
def
logLikelihood(vc: VectoI, vcp1: VectoI, vcp2: VectoI, popX: HMatrix5[Int], k: Int, me: Float = me_default): Double
Compute the Log-Likelihood for the given Bayesian Network structure and data.
Compute the Log-Likelihood for the given Bayesian Network structure and data.
- vc
the value count
- vcp1
the value count for parent 1
- vcp2
the value count for parent 2
- popX
the population counts
- k
the number of classes
- me
the m-estimate value
- Definition Classes
- BayesMetrics
-
def
reset(): Unit
Reset or re-initialize the frequency tables from global frequencies.
Reset or re-initialize the frequency tables from global frequencies.
- Definition Classes
- TwoBAN_OS → TwoBAN_OS0 → Classifier
-
def
scoreCMI(parent: MatrixI = parent, cmiMx: MatrixD): Double
Sum up the conditional mutual information score of the BN structure represented by 'parent'
Sum up the conditional mutual information score of the BN structure represented by 'parent'
- parent
parent/predecessor matrix (dim = n x 2)
- cmiMx
the conditional mutual information matrix
- Definition Classes
- TwoBAN_OS0
-
def
shiftToZero(): Unit
Shift the 'x' Matrix so that the minimum value for each column equals zero.
Shift the 'x' Matrix so that the minimum value for each column equals zero.
- Definition Classes
- ClassifierInt
-
def
size: Int
Return the number of data vectors in training/test-set (# rows).
Return the number of data vectors in training/test-set (# rows).
- Definition Classes
- ClassifierInt → Classifier
-
def
split(indices: IndexedSeq[Int], k: Int): Array[IndexedSeq[Int]]
Split 'indices' into 'k' arrays of equal sizes (perhaps except for the last one)
Split 'indices' into 'k' arrays of equal sizes (perhaps except for the last one)
- indices
the ParSeq to be splitted
- k
the number of pieces the vector is to be splitted
- Definition Classes
- BayesClassifier
-
def
test(itest: Array[Int]): Double
Test the quality of the training with a test-set and return the fraction of correct classifications.
Test the quality of the training with a test-set and return the fraction of correct classifications.
- itest
indices of the instances considered test data
- Definition Classes
- BayesClassifier
-
def
test(itest: VectorI): Double
Test the quality of the training with a test-set and return the fraction of correct classifications.
Test the quality of the training with a test-set and return the fraction of correct classifications.
- itest
indices of the instances considered test data
- Definition Classes
- ClassifierInt → Classifier
-
def
test(xx: MatrixI, yy: VectorI): Double
Test the quality of the training with a test-set and return the fraction of correct classifications.
Test the quality of the training with a test-set and return the fraction of correct classifications.
- xx
the integer-valued test vectors stored as rows of a matrix
- yy
the test classification vector, where 'yy_i = class' for row 'i' of 'xx'
- Definition Classes
- ClassifierInt
-
def
test(testStart: Int, testEnd: Int): Double
Test the quality of the training with a test-set and return the fraction of correct classifications.
Test the quality of the training with a test-set and return the fraction of correct classifications.
- testStart
beginning of test region (inclusive)
- testEnd
end of test region (exclusive)
- Definition Classes
- ClassifierInt → Classifier
-
def
toggleSmooth(): Unit
Toggle the value of the 'smooth' property.
Toggle the value of the 'smooth' property.
- Definition Classes
- BayesClassifier
-
def
train(itest: IndexedSeq[Int]): Unit
Train the classifier by computing the probabilities for C, and the conditional probabilities for X_j.
Train the classifier by computing the probabilities for C, and the conditional probabilities for X_j. This is the quick version that uses the "subtraction" method to achieve efficiency.
- itest
indices of the instances considered testing data
- Definition Classes
- TwoBAN_OS0 → Classifier
-
def
train(testStart: Int, testEnd: Int): Unit
Train the classifier by computing the probabilities for C, and the conditional probabilities for X_j.
Train the classifier by computing the probabilities for C, and the conditional probabilities for X_j.
- testStart
starting index of test region (inclusive) used in cross-validation.
- testEnd
ending index of test region. (exclusive) used in cross-validation.
- Definition Classes
- TwoBAN_OS0 → Classifier
-
def
train(): Unit
Given a set of data vectors and their classifications, build a classifier.
Given a set of data vectors and their classifications, build a classifier.
- Definition Classes
- Classifier
-
def
vc_default: VectorI
Return default values for binary input data (value count 'vc' set to 2).
Return default values for binary input data (value count 'vc' set to 2).
- Definition Classes
- ClassifierInt
-
def
vc_fromData: VectorI
Return value counts calculated from the input data.
Return value counts calculated from the input data. May wish to call 'shiftToZero' before calling this method.
- Definition Classes
- ClassifierInt
-
def
vc_fromData2(rg: Range): VectorI
Return value counts calculated from the input data.
Return value counts calculated from the input data. May wish to call 'shiftToZero' before calling this method.
- rg
the range of columns to be considered
- Definition Classes
- ClassifierInt