docs: public void run() {
      int maxruns = this.maxruns, maxsmall = this.maxsmall;
      double oldchi = getChiSq();
      while(maxruns-- > 0) {
        iterate();
        double newchi = getChiSq(), deltachi = newchi - oldchi;
        oldchi = newchi;
        // stop condition: only a small improvement in Chi.
        if(deltachi < 0 && deltachi > -small && --maxsmall < 0) {
          break;
        }
      }
    }