public PNormNormalization(double p){
  if (p <= 0 || Double.isNaN(p))   throw new IllegalArgumentException("p must be greater than zero, not " + p);
  this.p=p;
}

public PNormNormalization ( double p ) { if ( p <= 0 || Double . isNaN ( p ) ) throw new IllegalArgumentException ( "p must be greater than zero, not " + p ) ; this . p = p ; }
creates a new p norm
