Cash withdrawals and reinvestment

[uberdeveloper]

I wanted to simulate some realistic scenarios relating to systematic investment plan, cash withdrawals, and partial reinvestment.
Presently, I am manipulating the self._broker._cash attribute to this effect.

Is there any suggested approach?
I am more concerned about the execution rather than the returns as I am using attributes inside the Strategy class to calculate customized returns.

[kernc]

Manipulating self._broker._cash seems reasonable for the time being.

Watch out for "margin call" liquidations if equity ever becomes negative:

backtesting.py/backtesting/backtesting.py

Lines 741 to 743 in 28568d1

	@property
	def equity(self) -> float:
	return self._cash + sum(trade.pl for trade in self.trades)

[uberdeveloper]

This is the present workaround and it works fine.

class MyStrategy(Strategy):
    def init(self):
        # Anything above this capital in cash would be withdrawn
        self._initial_capital = 10000 
        # Everything else goes here

    def next(self):
        # After processing all logic
        
        # Withdraw only when there is excess
        if (self.equity > self._initial_capital) and (self._broker._cash > self._initial_capital):
            # Withdraw cash only when all positions are closed and everything is in cash
            if (self.position.size == 0):
                withdrawal = self._broker._cash - self._initial_capital
                self._broker._cash -= withdrawal

One big caveat is withdrawing cash when a position is already open.
Would post after experimenting this