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golearn/metrics/pairwise/rbf_kernel.go
Richard Townsend ff52c013eb Update gonum to latest version
Should fix #200 and #205
2018-03-24 00:19:35 +00:00

28 lines
604 B
Go

package pairwise
import (
"math"
"gonum.org/v1/gonum/mat"
)
type RBFKernel struct {
gamma float64
}
// NewRBFKernel returns a representation of a Radial Basis Function Kernel
func NewRBFKernel(gamma float64) *RBFKernel {
return &RBFKernel{gamma: gamma}
}
// InnerProduct computes the inner product through a kernel trick
// K(x, y) = exp(-gamma * ||x - y||^2)
func (r *RBFKernel) InnerProduct(vectorX *mat.Dense, vectorY *mat.Dense) float64 {
euclidean := NewEuclidean()
distance := euclidean.Distance(vectorX, vectorY)
result := math.Exp(-r.gamma * math.Pow(distance, 2))
return result
}