Package weka.core

Class BinarySparseInstance

java.lang.Object
weka.core.AbstractInstance
weka.core.SparseInstance
weka.core.BinarySparseInstance
All Implemented Interfaces:
Serializable, Copyable, Instance, 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: 12472 $
See Also:

  • Constructor Details

    • 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 Details

    • copy

      public Object copy()
      Produces a shallow copy of this instance. The copy has access to the same dataset. (if you want to make a copy that doesn't have access to the dataset, use new BinarySparseInstance(instance)
      Specified by:
      copy in interface Copyable
      Overrides:
      copy in class SparseInstance
      Returns:
      the shallow copy

    • copy

      public Instance copy(double[] values)
      Copies the instance but fills up its values based on the given array of doubles. The copy has access to the same dataset.
      Specified by:
      copy in interface Instance
      Overrides:
      copy in class SparseInstance
      Parameters:
      values - the array with new values
      Returns:
      the new instance

    • mergeInstance

      public Instance mergeInstance(Instance inst)
      Merges this instance with the given instance and returns the result. Dataset is set to null.
      Specified by:
      mergeInstance in interface Instance
      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.
      Specified by:
      replaceMissingValues in interface Instance
      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.
      Specified by:
      setValue in interface Instance
      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.
      Specified by:
      setValueSparse in interface Instance
      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.
      Specified by:
      toDoubleArray in interface Instance
      Overrides:
      toDoubleArray in class SparseInstance
      Returns:
      an array containing all the instance attribute values

    • toString

      public 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 AbstractInstance
      Returns:
      the instance's description as a string

    • value

      public double value(int attIndex)
      Returns an instance's attribute value in internal format.
      Specified by:
      value in interface Instance
      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.
      Specified by:
      valueSparse in interface Instance
      Overrides:
      valueSparse in class AbstractInstance
      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(String[] options)
      Main method for testing this class.
      Parameters:
      options - the command line options - ignored

    • getRevision

      public String getRevision()
      Returns the revision string.
      Specified by:
      getRevision in interface RevisionHandler
      Overrides:
      getRevision in class SparseInstance
      Returns:
      the revision