func (cov_func *CovSEARD) Cov(x1 *core.Vector, x2 *core.Vector) float64 {
ret := 0.0
tmp := 0.0
for key, r := range cov_func.Radiuses.Data {
v1 := x1.GetValue(key)
v2 := x2.GetValue(key)
tmp = (v1 - v2) / r
ret += tmp * tmp
}
ret = cov_func.Amp * math.Exp(-ret)
return ret
}
