public int t3Lookback( int optInTimePeriod,
      double optInVFactor )
   {
      if( (int)optInTimePeriod == ( Integer.MIN_VALUE ) )
         optInTimePeriod = 5;
      else if( ((int)optInTimePeriod < 2) || ((int)optInTimePeriod > 100000) )
         return -1;
      if( optInVFactor == (-4e+37) )
         optInVFactor = 7.000000e-1;
      else if( (optInVFactor < 0.000000e+0) || (optInVFactor > 1.000000e+0) )
         return -1;
      return 6 * (optInTimePeriod-1) + (this.unstablePeriod[FuncUnstId.T3.ordinal()]) ;
   }