private final double preNorm(NumberVector v,final int start,final int end){
  double agg=0.;
  for (int d=start; d < end; d++) {
    final double xd=v.doubleValue(d);
    final double delta=xd >= 0. ? xd : -xd;
    agg+=Math.pow(delta,p);
  }
  return agg;
}

private final double preNorm ( NumberVector v , final int start , final int end ) { double agg = 0. ; for ( int d = start ; d < end ; d ++ ) { final double xd = v . doubleValue ( d ) ; final double delta = xd >= 0. ? xd : - xd ; agg += Math . pow ( delta , p ) ; } return agg ; }
compute unscaled norm in a range of dimensions .
