public boolean isNaN(){
  return Double.isNaN(x.getReal()) || Double.isNaN(y.getReal()) || Double.isNaN(z.getReal());
}

public boolean isNaN ( ) { return Double . isNaN ( x . getReal ( ) ) || Double . isNaN ( y . getReal ( ) ) || Double . isNaN ( z . getReal ( ) ) ; }
returns true if any coordinate of this vector is nan ; false otherwise
