// ComputeCentroids Needs comments.
func ComputeCentroid(mat *matrix.DenseMatrix) (*matrix.DenseMatrix, error) {
rows, _ := mat.GetSize()
vectorSum := mat.SumCols()
if rows == 0 {
return vectorSum, errors.New("No points inputted")
}
vectorSum.Scale(1.0 / float64(rows))
return vectorSum, nil
}