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golearn/metrics/pairwise/rbf_kernel.go
2014-05-03 23:05:24 +08:00

28 lines
558 B
Go

package pairwise
import (
"math"
"github.com/gonum/matrix/mat64"
)
type RBFKernel struct {
gamma float64
}
// Radial Basis Function Kernel
func NewRBFKernel(gamma float64) *RBFKernel {
return &RBFKernel{gamma: gamma}
}
// Compute inner product through kernel trick
// K(x, y) = exp(-gamma * ||x - y||^2)
func (self *RBFKernel) InnerProduct(vectorX *mat64.Dense, vectorY *mat64.Dense) float64 {
euclidean := NewEuclidean()
distance := euclidean.Distance(vectorX, vectorY)
result := math.Exp(-self.gamma * math.Pow(distance, 2))
return result
}