weka.classifiers.functions

## Class SGD

- java.lang.Object
- - weka.classifiers.AbstractClassifier
  - - weka.classifiers.RandomizableClassifier
    - - weka.classifiers.functions.SGD

- All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, Classifier, UpdateableClassifier, Aggregateable<SGD>, BatchPredictor, CapabilitiesHandler, CapabilitiesIgnorer, OptionHandler, Randomizable, RevisionHandler

      public class SGD
      extends RandomizableClassifier
      implements UpdateableClassifier, OptionHandler, Aggregateable<SGD>

  Implements stochastic gradient descent for learning various linear models (binary class SVM, binary class logistic regression, squared loss, Huber loss and epsilon-insensitive loss linear regression). Globally replaces all missing values and transforms nominal attributes into binary ones. It also normalizes all attributes, so the coefficients in the output are based on the normalized data.
  For numeric class attributes, the squared, Huber or epsilon-insensitve loss function must be used. Epsilon-insensitive and Huber loss may require a much higher learning rate.

  Valid options are:

       -F
        Set the loss function to minimize.
        0 = hinge loss (SVM), 1 = log loss (logistic regression),
        2 = squared loss (regression), 3 = epsilon insensitive loss (regression),
        4 = Huber loss (regression).
        (default = 0)

       -L
        The learning rate. If normalization is
        turned off (as it is automatically for streaming data), then the
        default learning rate will need to be reduced (try 0.0001).
        (default = 0.01).

       -R <double>
        The lambda regularization constant (default = 0.0001)

       -E <integer>
        The number of epochs to perform (batch learning only, default = 500)

       -C <double>
        The epsilon threshold (epsilon-insenstive and Huber loss only, default = 1e-3)

       -N
        Don't normalize the data

       -M
        Don't replace missing values

       -S <num>
        Random number seed.
        (default 1)

       -output-debug-info
        If set, classifier is run in debug mode and
        may output additional info to the console

       -do-not-check-capabilities
        If set, classifier capabilities are not checked before classifier is built
        (use with caution).

  Version:
    $Revision: 11468 $
  Author:
    Eibe Frank (eibe{[at]}cs{[dot]}waikato{[dot]}ac{[dot]}nz), Mark Hall (mhall{[at]}pentaho{[dot]}com)
  See Also:
    Serialized Form

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `EPSILON_INSENSITIVE` The epsilon insensitive loss function
    `static int` | `HINGE` the hinge loss function.
    `static int` | `HUBER` The Huber loss function
    `static int` | `LOGLOSS` the log loss function.
    `static int` | `SQUAREDLOSS` the squared loss function.
    `static Tag[]` | `TAGS_SELECTION` Loss functions to choose from

    - ### Fields inherited from class weka.classifiers.AbstractClassifier

      `NUM_DECIMAL_PLACES_DEFAULT`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `SGD()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `SGD` | `aggregate(SGD toAggregate)` Aggregate an object with this one
    `void` | `buildClassifier(Instances data)` Method for building the classifier.
    `double[]` | `distributionForInstance(Instance inst)` Computes the distribution for a given instance
    `java.lang.String` | `dontNormalizeTipText()` Returns the tip text for this property
    `java.lang.String` | `dontReplaceMissingTipText()` Returns the tip text for this property
    `java.lang.String` | `epochsTipText()` Returns the tip text for this property
    `java.lang.String` | `epsilonTipText()` Returns the tip text for this property
    `void` | `finalizeAggregation()` Call to complete the aggregation process.
    `Capabilities` | `getCapabilities()` Returns default capabilities of the classifier.
    `boolean` | `getDontNormalize()` Get whether normalization has been turned off.
    `boolean` | `getDontReplaceMissing()` Get whether global replacement of missing values has been disabled.
    `int` | `getEpochs()` Get current number of epochs
    `double` | `getEpsilon()` Get the epsilon threshold on the error for epsilon insensitive and Huber loss functions
    `double` | `getLambda()` Get the current value of lambda
    `double` | `getLearningRate()` Get the learning rate.
    `SelectedTag` | `getLossFunction()` Get the current loss function.
    `java.lang.String[]` | `getOptions()` Gets the current settings of the classifier.
    `java.lang.String` | `getRevision()` Returns the revision string.
    `double[]` | `getWeights()`
    `java.lang.String` | `globalInfo()` Returns a string describing classifier
    `java.lang.String` | `lambdaTipText()` Returns the tip text for this property
    `java.lang.String` | `learningRateTipText()` Returns the tip text for this property
    `java.util.Enumeration<Option>` | `listOptions()` Returns an enumeration describing the available options.
    `java.lang.String` | `lossFunctionTipText()` Returns the tip text for this property
    `static void` | `main(java.lang.String[] args)` Main method for testing this class.
    `void` | `reset()` Reset the classifier.
    `void` | `setDontNormalize(boolean m)` Turn normalization off/on.
    `void` | `setDontReplaceMissing(boolean m)` Turn global replacement of missing values off/on.
    `void` | `setEpochs(int e)` Set the number of epochs to use
    `void` | `setEpsilon(double e)` Set the epsilon threshold on the error for epsilon insensitive and Huber loss functions
    `void` | `setLambda(double lambda)` Set the value of lambda to use
    `void` | `setLearningRate(double lr)` Set the learning rate.
    `void` | `setLossFunction(SelectedTag function)` Set the loss function to use.
    `void` | `setOptions(java.lang.String[] options)` Parses a given list of options.
    `java.lang.String` | `toString()` Prints out the classifier.
    `void` | `updateClassifier(Instance instance)` Updates the classifier with the given instance.

    - ### Methods inherited from class weka.classifiers.RandomizableClassifier

      `getSeed, seedTipText, setSeed`

    - ### Methods inherited from class weka.classifiers.AbstractClassifier

      `batchSizeTipText, classifyInstance, debugTipText, distributionsForInstances, doNotCheckCapabilitiesTipText, forName, getBatchSize, getDebug, getDoNotCheckCapabilities, getNumDecimalPlaces, implementsMoreEfficientBatchPrediction, makeCopies, makeCopy, numDecimalPlacesTipText, runClassifier, setBatchSize, setDebug, setDoNotCheckCapabilities, setNumDecimalPlaces`

    - ### Methods inherited from class java.lang.Object

      `equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Field Detail

    - #### HINGE

          public static final int HINGE

      the hinge loss function.
      See Also:
        Constant Field Values

    - #### LOGLOSS

          public static final int LOGLOSS

      the log loss function.
      See Also:
        Constant Field Values

    - #### SQUAREDLOSS

          public static final int SQUAREDLOSS

      the squared loss function.
      See Also:
        Constant Field Values

    - #### EPSILON_INSENSITIVE

          public static final int EPSILON_INSENSITIVE

      The epsilon insensitive loss function
      See Also:
        Constant Field Values

    - #### HUBER

          public static final int HUBER

      The Huber loss function
      See Also:
        Constant Field Values

    - #### TAGS_SELECTION

          public static final Tag[] TAGS_SELECTION

      Loss functions to choose from

  - ### Constructor Detail

    - #### SGD

          public SGD()

  - ### Method Detail

    - #### getCapabilities

          public Capabilities getCapabilities()

      Returns default capabilities of the classifier.
      Specified by:
        `getCapabilities` in interface `Classifier`
      Specified by:
        `getCapabilities` in interface `CapabilitiesHandler`
      Overrides:
        `getCapabilities` in class `AbstractClassifier`
      Returns:
        the capabilities of this classifier
      See Also:
        `Capabilities`

    - #### epsilonTipText

          public java.lang.String epsilonTipText()

      Returns the tip text for this property
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### setEpsilon

          public void setEpsilon(double e)

      Set the epsilon threshold on the error for epsilon insensitive and Huber loss functions
      Parameters:
        `e` - the value of epsilon to use

    - #### getEpsilon

          public double getEpsilon()

      Get the epsilon threshold on the error for epsilon insensitive and Huber loss functions
      Returns:
        the value of epsilon to use

    - #### lambdaTipText

          public java.lang.String lambdaTipText()

      Returns the tip text for this property
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### setLambda

          public void setLambda(double lambda)

      Set the value of lambda to use
      Parameters:
        `lambda` - the value of lambda to use

    - #### getLambda

          public double getLambda()

      Get the current value of lambda
      Returns:
        the current value of lambda

    - #### setLearningRate

          public void setLearningRate(double lr)

      Set the learning rate.
      Parameters:
        `lr` - the learning rate to use.

    - #### getLearningRate

          public double getLearningRate()

      Get the learning rate.
      Returns:
        the learning rate

    - #### learningRateTipText

          public java.lang.String learningRateTipText()

      Returns the tip text for this property
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### epochsTipText

          public java.lang.String epochsTipText()

      Returns the tip text for this property
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### setEpochs

          public void setEpochs(int e)

      Set the number of epochs to use
      Parameters:
        `e` - the number of epochs to use

    - #### getEpochs

          public int getEpochs()

      Get current number of epochs
      Returns:
        the current number of epochs

    - #### setDontNormalize

          public void setDontNormalize(boolean m)

      Turn normalization off/on.
      Parameters:
        `m` - true if normalization is to be disabled.

    - #### getDontNormalize

          public boolean getDontNormalize()

      Get whether normalization has been turned off.
      Returns:
        true if normalization has been disabled.

    - #### dontNormalizeTipText

          public java.lang.String dontNormalizeTipText()

      Returns the tip text for this property
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### setDontReplaceMissing

          public void setDontReplaceMissing(boolean m)

      Turn global replacement of missing values off/on. If turned off, then missing values are effectively ignored.
      Parameters:
        `m` - true if global replacement of missing values is to be turned off.

    - #### getDontReplaceMissing

          public boolean getDontReplaceMissing()

      Get whether global replacement of missing values has been disabled.
      Returns:
        true if global replacement of missing values has been turned off

    - #### dontReplaceMissingTipText

          public java.lang.String dontReplaceMissingTipText()

      Returns the tip text for this property
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### setLossFunction

          public void setLossFunction(SelectedTag function)

      Set the loss function to use.
      Parameters:
        `function` - the loss function to use.

    - #### getLossFunction

          public SelectedTag getLossFunction()

      Get the current loss function.
      Returns:
        the current loss function.

    - #### lossFunctionTipText

          public java.lang.String lossFunctionTipText()

      Returns the tip text for this property
      Returns:
        tip text for this property suitable for displaying in the explorer/experimenter gui

    - #### listOptions

          public java.util.Enumeration<Option> listOptions()

      Returns an enumeration describing the available options.
      Specified by:
        `listOptions` in interface `OptionHandler`
      Overrides:
        `listOptions` in class `RandomizableClassifier`
      Returns:
        an enumeration of all the available options.

    - #### setOptions

          public void setOptions(java.lang.String[] options)
                          throws java.lang.Exception

      Parses a given list of options.

      Valid options are:

           -F
            Set the loss function to minimize.
            0 = hinge loss (SVM), 1 = log loss (logistic regression),
            2 = squared loss (regression), 3 = epsilon insensitive loss (regression),
            4 = Huber loss (regression).
            (default = 0)

           -L
            The learning rate. If normalization is
            turned off (as it is automatically for streaming data), then the
            default learning rate will need to be reduced (try 0.0001).
            (default = 0.01).

           -R <double>
            The lambda regularization constant (default = 0.0001)

           -E <integer>
            The number of epochs to perform (batch learning only, default = 500)

           -C <double>
            The epsilon threshold (epsilon-insenstive and Huber loss only, default = 1e-3)

           -N
            Don't normalize the data

           -M
            Don't replace missing values

           -S <num>
            Random number seed.
            (default 1)

           -output-debug-info
            If set, classifier is run in debug mode and
            may output additional info to the console

           -do-not-check-capabilities
            If set, classifier capabilities are not checked before classifier is built
            (use with caution).

      Specified by:
        `setOptions` in interface `OptionHandler`
      Overrides:
        `setOptions` in class `RandomizableClassifier`
      Parameters:
        `options` - the list of options as an array of strings
      Throws:
        `java.lang.Exception` - if an option is not supported

    - #### getOptions

          public java.lang.String[] getOptions()

      Gets the current settings of the classifier.
      Specified by:
        `getOptions` in interface `OptionHandler`
      Overrides:
        `getOptions` in class `RandomizableClassifier`
      Returns:
        an array of strings suitable for passing to setOptions

    - #### globalInfo

          public java.lang.String globalInfo()

      Returns a string describing classifier
      Returns:
        a description suitable for displaying in the explorer/experimenter gui

    - #### reset

          public void reset()

      Reset the classifier.

    - #### buildClassifier

          public void buildClassifier(Instances data)
                               throws java.lang.Exception

      Method for building the classifier.
      Specified by:
        `buildClassifier` in interface `Classifier`
      Parameters:
        `data` - the set of training instances.
      Throws:
        `java.lang.Exception` - if the classifier can't be built successfully.

    - #### updateClassifier

          public void updateClassifier(Instance instance)
                                throws java.lang.Exception

      Updates the classifier with the given instance.
      Specified by:
        `updateClassifier` in interface `UpdateableClassifier`
      Parameters:
        `instance` - the new training instance to include in the model
      Throws:
        `java.lang.Exception` - if the instance could not be incorporated in the model.

    - #### distributionForInstance

          public double[] distributionForInstance(Instance inst)
                                           throws java.lang.Exception

      Computes the distribution for a given instance
      Specified by:
        `distributionForInstance` in interface `Classifier`
      Overrides:
        `distributionForInstance` in class `AbstractClassifier`
      Parameters:
        `instance` - the instance for which distribution is computed
      Returns:
        the distribution
      Throws:
        `java.lang.Exception` - if the distribution can't be computed successfully

    - #### getWeights

          public double[] getWeights()

    - #### toString

          public java.lang.String toString()

      Prints out the classifier.
      Overrides:
        `toString` in class `java.lang.Object`
      Returns:
        a description of the classifier as a string

    - #### getRevision

          public java.lang.String getRevision()

      Returns the revision string.
      Specified by:
        `getRevision` in interface `RevisionHandler`
      Overrides:
        `getRevision` in class `AbstractClassifier`
      Returns:
        the revision

    - #### aggregate

          public SGD aggregate(SGD toAggregate)
                        throws java.lang.Exception

      Aggregate an object with this one
      Specified by:
        `aggregate` in interface `Aggregateable<SGD>`
      Parameters:
        `toAggregate` - the object to aggregate
      Returns:
        the result of aggregation
      Throws:
        `java.lang.Exception` - if the supplied object can't be aggregated for some reason

    - #### finalizeAggregation

          public void finalizeAggregation()
                                   throws java.lang.Exception

      Call to complete the aggregation process. Allows implementers to do any final processing based on how many objects were aggregated.
      Specified by:
        `finalizeAggregation` in interface `Aggregateable<SGD>`
      Throws:
        `java.lang.Exception` - if the aggregation can't be finalized for some reason

    - #### main

          public static void main(java.lang.String[] args)

      Main method for testing this class.