## org.biojava.stats.svm
Class RadialBaseKernel

    java.lang.Object
      org.biojava.stats.svm.NestedKernel
          org.biojava.stats.svm.RadialBaseKernel

All Implemented Interfaces:
  Serializable, SVMKernel

    public class RadialBaseKernel

extends NestedKernel

This kernel computes the radial base kernel that corresponds to a gausian distribution.

The formula for this is `exp( -||a - b|| / (2* width ^ 2))`. The term a-b can be represented in an arbitrary feature space by using a nested kernel k, and becomes `k(a, a) + k(b, b) - 2 * k(a, b)`.

As k(x, x) is required repeatedly, I suggest using a DiagonalCachingKernel as the immediately nested kernel function.

Author:
  Matthew Pocock
See Also:
  Serialized Form

Constructor Summary
`RadialBaseKernel()`
`RadialBaseKernel(SVMKernel nested, double width)`

Method Summary
`double` `evaluate(Object a, Object b)` Return the dot product of two vectors in an arbitrary feature space.
`double` `getWidth()`
`void` `setWidth(double width)`
`String` `toString()`

Methods inherited from class org.biojava.stats.svm.NestedKernel
`getNestedKernel, setNestedKernel`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Constructor Detail

### RadialBaseKernel

    public RadialBaseKernel()

### RadialBaseKernel

    public RadialBaseKernel(SVMKernel nested,
                            double width)

Method Detail

### evaluate

    public double evaluate(Object a,
                           Object b)

  Description copied from interface: `SVMKernel`
  Return the dot product of two vectors in an arbitrary feature space. In this implementation, the `vectors' can actually be arbitrary objects.

### getWidth

    public double getWidth()

### setWidth

    public void setWidth(double width)

### toString

    public String toString()

  Overrides:
    `toString` in class `Object`