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Class weka.core.SparseInstance
java.lang.Object
|
+----weka.core.Instance
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+----weka.core.SparseInstance
- public class SparseInstance
- extends Instance
Class for storing an 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 will be stored
explicitly.
SparseInstance(double, double[])
- Constructor that generates a sparse instance from the given
parameters.
SparseInstance(double, double[], int[], int)
- Constructor that inititalizes instance variable with given
values.
SparseInstance(Instance)
- Constructor that generates a sparse instance from the given
instance.
SparseInstance(int)
- Constructor of an instance that sets weight to one, all values to
be missing, and the reference to the dataset to null.
SparseInstance(SparseInstance)
- Constructor that copies the info from the given instance.
attributeSparse(int)
- Returns the attribute associated with the internal index.
copy()
- Produces a shallow copy of this instance.
index(int)
- Returns the index of the attribute stored at the given position.
isMissing(int)
- Tests if a specific value is "missing".
locateIndex(int)
- Locates the greatest index that is not greater than the
given index.
main(String[])
- Main method for testing this class.
mergeInstance(Instance)
- Merges this instance with the given instance and returns
the result.
numAttributes()
- Returns the number of attributes.
numValues()
- Returns the number of values in the sparse vector.
replaceMissingValues(double[])
- Replaces all missing values in the instance with the
values contained in the given array.
setValue(int, double)
- Sets a specific value in the instance to the given value
(internal floating-point format).
setValueSparse(int, double)
- Sets a specific value in the instance to the given value
(internal floating-point format).
toDoubleArray()
- Returns the values of each attribute as an array of doubles.
toString()
- Returns the description of one instance in sparse format.
value(int)
- Returns an instance's attribute value in internal format.
SparseInstance
public SparseInstance(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
SparseInstance
public SparseInstance(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
SparseInstance
public SparseInstance(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
SparseInstance
public SparseInstance(double weight,
double attValues[],
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
attValues
- a vector of attribute values (just the ones to be stored)
indices
- the indices of the given values in the full vector
maxNumValues
- the maximium number of values that can be stored
SparseInstance
public SparseInstance(int numAttributes)
Constructor of an instance that sets weight to one, all values to
be missing, 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
attributeSparse
public Attribute attributeSparse(int indexOfIndex)
Returns the attribute associated with the internal index.
- Parameters:
indexOfIndex
- the index of the attribute's index
- Returns:
- the attribute at the given position
- Throws:
- UnassignedDatasetException - if instance doesn't have access to a
dataset
- Overrides:
- attributeSparse in class Instance
copy
public java.lang.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 SparseInstance(instance)
- Returns:
- the shallow copy
- Overrides:
- copy in class Instance
index
public int index(int position)
Returns the index of the attribute stored at the given position.
- Parameters:
position
- the position
- Returns:
- the index of the attribute stored at the given position
- Overrides:
- index in class Instance
isMissing
public boolean isMissing(int attIndex)
Tests if a specific value is "missing".
- Parameters:
attIndex
- the attribute's index
- Overrides:
- isMissing in class Instance
locateIndex
public int locateIndex(int index)
Locates the greatest index that is not greater than the
given index.
- Returns:
- the internal index of the attribute index. Returns
-1 if no index with this property couldn't be found
mergeInstance
public Instance mergeInstance(Instance inst)
Merges this instance with the given instance and returns
the result. Dataset is set to null.
- Parameters:
inst
- the instance to be merged with this one
- Returns:
- the merged instances
- Overrides:
- mergeInstance in class Instance
numAttributes
public int numAttributes()
Returns the number of attributes.
- Returns:
- the number of attributes as an integer
- Overrides:
- numAttributes in class Instance
numValues
public int numValues()
Returns the number of values in the sparse vector.
- Returns:
- the number of values
- Overrides:
- numValues in class Instance
replaceMissingValues
public void replaceMissingValues(double array[])
Replaces all missing values in the instance with the
values contained in the given array. A deep copy of
the vector of attribute values is performed before the
values are replaced.
- Parameters:
array
- containing the means and modes
- Throws:
- java.lang.IllegalArgumentException - if numbers of attributes are unequal
- Overrides:
- replaceMissingValues in class Instance
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.
- 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).
- Overrides:
- setValue in class Instance
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.
- 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).
- Overrides:
- setValueSparse in class Instance
toDoubleArray
public double[] toDoubleArray()
Returns the values of each attribute as an array of doubles.
- Returns:
- an array containing all the instance attribute values
- Overrides:
- toDoubleArray in class Instance
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.
- Returns:
- the instance's description as a string
- Overrides:
- toString in class Instance
value
public double value(int attIndex)
Returns an instance's attribute value in internal format.
- 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).
- Overrides:
- value in class Instance
main
public static void main(java.lang.String options[])
Main method for testing this class.
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