This ProBuilder code snippet demonstrates how to dynamically adjust the trading lot size based on the performance of a trading strategy. The lot size increases or decreases based on the equity change, aiming to compound gains or reduce risk during drawdowns.

ONCE MyEquity = 10000
ONCE nLots = 1
IF Not OnMarket THEN
    IF Strategyprofit >= (MyEquity * 1.03) THEN
        MyEquity = Strategyprofit
        nLots = nLots + 1
    ELSIF Strategyprofit <= (MyEquity * 0.97) THEN
        MyEquity = Strategyprofit
        nLots = nLots - 1
        nLots = max(1, nLots) //do not allow nLots to fall below 1
    ENDIF
ENDIF

Explanation of the Code:

• Initialization: The variables MyEquity and nLots are initialized to 10000 and 1, respectively. These represent the starting equity and number of lots.
• Market Condition Check: The IF Not OnMarket condition ensures that adjustments are made only when not currently in a market position.
• Profit Evaluation: The code checks if the strategy profit has increased by at least 3% of the current equity (MyEquity * 1.03). If true, it updates the equity to the current strategy profit and increments the lot size by 1.
• Loss Evaluation: Conversely, if the strategy profit decreases by 3% or more (MyEquity * 0.97), the equity is updated, and the lot size is decreased by 1. However, the max function ensures that the lot size does not fall below 1, maintaining a minimum trading size.

This approach helps in scaling the trading size according to performance, potentially maximizing gains during profitable periods and minimizing losses during downturns.