The trading system based on the ColorXPWMA_Digit indicator signals with an ability to change the volume of a forthcoming trade depending on the results of the previous trades for this trading system. Trading signals are formed at the bar close, provided that the trend has changed (which is indicated by a change in the indicator line color).
The block of input EA variables is added for managing volumes of opened positions:
input uint    BuyTotalMMTriger=5; // The number of the last Buy deals to calculate stop loss input uint    BuyLossMMTriger=3;  // The number of losing Buy deals to reduce MM input uint    SellTotalMMTriger=5;// The number of the last Sell deals to calculate stop loss input uint    SellLossMMTriger=3; // The number of losing Sell deals to reduce MM input double  SmallMM_=0.01;      // Share of a deposit in a deal in case of loss input double  MM=0.1;            // Share of a deposit in a deal during normal trading input MarginMode MMMode=LOT;      // Lot value determining method
In case of such inputs and when selecting from the last five trades, three of which are loss-making in a single direction, the EA opens the next trade in the same direction having the volume of 0.01 lot. If there are less than three loss-making trades out of the last five ones, the position volume is 0.1.
For the generated EA to operate correctly, the compiled ColorXPWMA_Digit.ex5 indicator file must be available under the <terminal_data_directory>\MQL5\Indicators folder.
Default Expert Advisor’s input parameters with stops have been used during tests shown below.
Fig. 1. Example trades on the chart
GBPJPY H1 testing results over the year of 2017:
Fig. 2. Test results chart