public void calculateMin(double min){
  if (this.min == -1) {
    this.min=min;
  }
 else {
    this.min=Math.min(this.min,min);
  }
}

public void calculateMin ( double min ) { if ( this . min == - 1 ) { this . min = min ; } else { this . min = Math . min ( this . min , min ) ; } }
sets the minimum and deals with the - 1 initialization ! .
