Package weka.core

Class BinarySparseInstance

  • All Implemented Interfaces:
    java.io.Serializable, Copyable, RevisionHandler

    public class BinarySparseInstance
    extends SparseInstance
    Class for storing a binary-data-only instance as a sparse vector. A sparse instance only requires storage for those attribute values that are non-zero. Since the objective is to reduce storage requirements for datasets with large numbers of default values, this also includes nominal attributes -- the first nominal value (i.e. that which has index 0) will not require explicit storage, so rearrange your nominal attribute value orderings if necessary. Missing values are not supported, and will be treated as 1 (true).
    Version:
    $Revision: 1.13 $
    See Also:
    Serialized Form
    • Constructor Detail

      • BinarySparseInstance

        public BinarySparseInstance​(Instance instance)
        Constructor that generates a sparse instance from the given instance. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)
        Parameters:
        instance - the instance from which the attribute values and the weight are to be copied
      • BinarySparseInstance

        public BinarySparseInstance​(SparseInstance instance)
        Constructor that copies the info from the given instance. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)
        Parameters:
        instance - the instance from which the attribute info is to be copied
      • BinarySparseInstance

        public BinarySparseInstance​(double weight,
                                    double[] attValues)
        Constructor that generates a sparse instance from the given parameters. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)
        Parameters:
        weight - the instance's weight
        attValues - a vector of attribute values
      • BinarySparseInstance

        public BinarySparseInstance​(double weight,
                                    int[] indices,
                                    int maxNumValues)
        Constructor that inititalizes instance variable with given values. Reference to the dataset is set to null. (ie. the instance doesn't have access to information about the attribute types)
        Parameters:
        weight - the instance's weight
        indices - the indices of the given values in the full vector
        maxNumValues - the maximium number of values that can be stored
      • BinarySparseInstance

        public BinarySparseInstance​(int numAttributes)
        Constructor of an instance that sets weight to one, all values to 1, and the reference to the dataset to null. (ie. the instance doesn't have access to information about the attribute types)
        Parameters:
        numAttributes - the size of the instance
    • Method Detail

      • copy

        public java.lang.Object copy()
        Produces a shallow copy of this instance. The copy doesn't have access to a dataset.
        Specified by:
        copy in interface Copyable
        Overrides:
        copy in class SparseInstance
        Returns:
        the shallow copy
      • mergeInstance

        public Instance mergeInstance​(Instance inst)
        Merges this instance with the given instance and returns the result. Dataset is set to null.
        Overrides:
        mergeInstance in class SparseInstance
        Parameters:
        inst - the instance to be merged with this one
        Returns:
        the merged instances
      • replaceMissingValues

        public void replaceMissingValues​(double[] array)
        Does nothing, since we don't support missing values.
        Overrides:
        replaceMissingValues in class SparseInstance
        Parameters:
        array - containing the means and modes
      • setValue

        public void setValue​(int attIndex,
                             double value)
        Sets a specific value in the instance to the given value (internal floating-point format). Performs a deep copy of the vector of attribute values before the value is set.
        Overrides:
        setValue in class SparseInstance
        Parameters:
        attIndex - the attribute's index
        value - the new attribute value (If the corresponding attribute is nominal (or a string) then this is the new value's index as a double).
      • setValueSparse

        public void setValueSparse​(int indexOfIndex,
                                   double value)
        Sets a specific value in the instance to the given value (internal floating-point format). Performs a deep copy of the vector of attribute values before the value is set.
        Overrides:
        setValueSparse in class SparseInstance
        Parameters:
        indexOfIndex - the index of the attribute's index
        value - the new attribute value (If the corresponding attribute is nominal (or a string) then this is the new value's index as a double).
      • toDoubleArray

        public double[] toDoubleArray()
        Returns the values of each attribute as an array of doubles.
        Overrides:
        toDoubleArray in class SparseInstance
        Returns:
        an array containing all the instance attribute values
      • toString

        public java.lang.String toString()
        Returns the description of one instance in sparse format. If the instance doesn't have access to a dataset, it returns the internal floating-point values. Quotes string values that contain whitespace characters.
        Overrides:
        toString in class SparseInstance
        Returns:
        the instance's description as a string
      • value

        public double value​(int attIndex)
        Returns an instance's attribute value in internal format.
        Overrides:
        value in class SparseInstance
        Parameters:
        attIndex - the attribute's index
        Returns:
        the specified value as a double (If the corresponding attribute is nominal (or a string) then it returns the value's index as a double).
      • valueSparse

        public final double valueSparse​(int indexOfIndex)
        Returns an instance's attribute value in internal format. Does exactly the same thing as value() if applied to an Instance.
        Overrides:
        valueSparse in class Instance
        Parameters:
        indexOfIndex - the index of the attribute's index
        Returns:
        the specified value as a double (If the corresponding attribute is nominal (or a string) then it returns the value's index as a double).
      • main

        public static void main​(java.lang.String[] options)
        Main method for testing this class.
        Parameters:
        options - the command line options - ignored