smile.math.kernel

Class SparseThinPlateSplineKernel

java.lang.Object

smile.math.kernel.ThinPlateSpline

smile.math.kernel.SparseThinPlateSplineKernel

All Implemented Interfaces:

java.io.Serializable, java.util.function.ToDoubleBiFunction<SparseArray,SparseArray>, Function, IsotropicKernel, MercerKernel<SparseArray>

public class SparseThinPlateSplineKernel
extends ThinPlateSpline
implements MercerKernel<SparseArray>

The Thin Plate Spline kernel on sparse data.

     k(u, v) = (||u-v|| / σ)2 log (||u-v|| / σ)
 

where σ > 0 is the scale parameter of the kernel.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SparseThinPlateSplineKernel(double sigma) Constructor.
SparseThinPlateSplineKernel(double sigma, double lo, double hi) Constructor.

Method Summary

Modifier and Type	Method and Description
double[]	hi() Returns the upper bound of hyperparameters.
double[]	hyperparameters() Returns the hyperparameters for tuning.
double	k(SparseArray x, SparseArray y) Kernel function.
double[]	kg(SparseArray x, SparseArray y) Computes the kernel and its gradient over hyperparameters.
double[]	lo() Returns the lower bound of hyperparameters.
SparseThinPlateSplineKernel	of(double[] params) Returns the same kind kernel with the new hyperparameters.

Methods inherited from class smile.math.kernel.ThinPlateSpline

k, kg, scale, 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

Methods inherited from interface smile.math.kernel.IsotropicKernel

apply, f, K, KG

Constructor Detail

SparseThinPlateSplineKernel

public SparseThinPlateSplineKernel(double sigma)

Constructor.

Parameters:

sigma - The length scale of kernel.

SparseThinPlateSplineKernel

public SparseThinPlateSplineKernel(double sigma,
                                   double lo,
                                   double hi)

Constructor.

Parameters:

sigma - The length scale of kernel.

lo - The lower bound of length scale for hyperparameter tuning.

hi - The upper bound of length scale for hyperparameter tuning.

Method Detail

k

public double k(SparseArray x,
                SparseArray y)

Description copied from interface: MercerKernel

Kernel function.

Specified by:

k in interface MercerKernel<SparseArray>

kg

public double[] kg(SparseArray x,
                   SparseArray y)

Description copied from interface: MercerKernel

Computes the kernel and its gradient over hyperparameters.

Specified by:

kg in interface MercerKernel<SparseArray>

of

public SparseThinPlateSplineKernel of(double[] params)

Description copied from interface: MercerKernel

Returns the same kind kernel with the new hyperparameters.

Specified by:

of in interface MercerKernel<SparseArray>

hyperparameters

public double[] hyperparameters()

Description copied from interface: MercerKernel

Returns the hyperparameters for tuning.

Specified by:

hyperparameters in interface MercerKernel<SparseArray>

lo

public double[] lo()

Description copied from interface: MercerKernel

Returns the lower bound of hyperparameters.

Specified by:

lo in interface MercerKernel<SparseArray>

hi

public double[] hi()

Description copied from interface: MercerKernel

Returns the upper bound of hyperparameters.

Specified by:

hi in interface MercerKernel<SparseArray>