//Computes the Euclidean distance between two vectors.
func (KNN *KNNClassifier) ComputeDistance(vector *mat.DenseMatrix, testrow *mat.DenseMatrix) float64 {
var sum float64
difference, err := testrow.MinusDense(vector)
flat := difference.Array()
if err != nil {
fmt.Println(err)
}
for _, i := range flat {
squared := math.Pow(i, 2)
sum += squared
}
eucdistance := math.Sqrt(sum)
return eucdistance
}