Package smile.math.kernel

Class PearsonKernel

java.lang.Object
smile.math.kernel.PearsonKernel
All Implemented Interfaces:
Serializable, ToDoubleBiFunction<double[],double[]>, MercerKernel<double[]>
public class PearsonKernel extends Object implements MercerKernel<double[]>
Pearson VII universal kernel. The Pearson VII function is often used for curve fitting of X-ray diffraction scans and single bands in infrared spectra.

References

  1. B. Üstün, W.J. Melssen, and L. Buydens. Facilitating the Application of Support Vector Regression by Using a Universal Pearson VII Function Based Kernel, 2006.
See Also:

  • Constructor Summary

    Constructors
    Constructor
    Description
    PearsonKernel(double sigma, double omega)
    Constructor.
    PearsonKernel(double sigma, double omega, double lo, double hi)
    Constructor.

  • Method Summary

    Modifier and Type
    Method
    Description
    double[]
    hi()
    Returns the upper bound of hyperparameters (in hyperparameter tuning).
    double[]
    hyperparameters()
    Returns the hyperparameters of kernel.
    double
    k(double[] x, double[] y)
    Kernel function.
    double[]
    kg(double[] x, double[] y)
    Computes the kernel and its gradient over hyperparameters.
    double[]
    lo()
    Returns the lower bound of hyperparameters (in hyperparameter tuning).
    PearsonKernel
    of(double[] params)
    Returns the same kind kernel with the new hyperparameters.
    double
    omega()
    Returns the tailing factor of the peak.
    double
    sigma()
    Returns Pearson width.
    String
    toString()
     

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

    Methods inherited from interface smile.math.kernel.MercerKernel

    apply, applyAsDouble, K, K, KG

  • Constructor Details

    • PearsonKernel

      public PearsonKernel(double sigma, double omega)
      Constructor.
      Parameters:
      sigma - Pearson width.
      omega - The tailing factor of the peak.

    • PearsonKernel

      public PearsonKernel(double sigma, double omega, double lo, double hi)
      Constructor.
      Parameters:
      sigma - Pearson width.
      omega - The tailing factor of the peak. The tailing factor is fixed during hyperparameter tuning.
      lo - The lower bound of length scale for hyperparameter tuning.
      hi - The upper bound of length scale for hyperparameter tuning.

  • Method Details

    • sigma

      public double sigma()
      Returns Pearson width.
      Returns:
      Pearson width.

    • omega

      public double omega()
      Returns the tailing factor of the peak.
      Returns:
      the tailing factor of the peak.

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • k

      public double k(double[] x, double[] y)
      Description copied from interface: MercerKernel
      Kernel function.
      Specified by:
      k in interface MercerKernel<double[]>
      Parameters:
      x - an object.
      y - an object.
      Returns:
      the kernel value.

    • kg

      public double[] kg(double[] x, double[] y)
      Description copied from interface: MercerKernel
      Computes the kernel and its gradient over hyperparameters.
      Specified by:
      kg in interface MercerKernel<double[]>
      Parameters:
      x - an object.
      y - an object.
      Returns:
      the kernel value and gradient.

    • of

      public PearsonKernel of(double[] params)
      Description copied from interface: MercerKernel
      Returns the same kind kernel with the new hyperparameters.
      Specified by:
      of in interface MercerKernel<double[]>
      Parameters:
      params - the hyperparameters.
      Returns:
      the same kind kernel with the new hyperparameters.

    • hyperparameters

      public double[] hyperparameters()
      Description copied from interface: MercerKernel
      Returns the hyperparameters of kernel.
      Specified by:
      hyperparameters in interface MercerKernel<double[]>
      Returns:
      the hyperparameters of kernel.

    • lo

      public double[] lo()
      Description copied from interface: MercerKernel
      Returns the lower bound of hyperparameters (in hyperparameter tuning).
      Specified by:
      lo in interface MercerKernel<double[]>
      Returns:
      the lower bound of hyperparameters.

    • hi

      public double[] hi()
      Description copied from interface: MercerKernel
      Returns the upper bound of hyperparameters (in hyperparameter tuning).
      Specified by:
      hi in interface MercerKernel<double[]>
      Returns:
      the upper bound of hyperparameters.