Function that self-optimize few EAs parameters basing on x days of hisotry.

Please simply explain next to code line where to set x days and ranges for self-optimization  for 3 inputs below. It will be best if each input has its own function. Self-optimization should be done as often as possible :

 Parts of code with underlined inputs to be auto-optimized: 

 input int inpATRPeriod = 14; //ATR Period             

///... 

   change = DoubleToString((((SymbolInfoDouble(_Symbol,SYMBOL_BID)-PositionGetDouble(POSITION_PRICE_OPEN)) / PositionGetDouble(POSITION_PRICE_OPEN)) *100), 3);

                  if(

                     change > InpProfitPercent + ATR()*InpATR_TP_Weight || change < InpDrawdown - ATR()*InpATR_SL_Weight

///...

 change = DoubleToString((((PositionGetDouble(POSITION_PRICE_OPEN)-SymbolInfoDouble(_Symbol,SYMBOL_ASK)) / PositionGetDouble(POSITION_PRICE_OPEN)) *100), 3);

                         change > InpProfitPercent + ATR()*InpATR_TP_Weight || change < InpDrawdown - ATR()*InpATR_SL_Weight

Thank You!