How can I create a sizer based on value?

[chrix]

I'm having trouble using the PercentSizer for live trading, because if I have a big short position what the sizer sees as cash is far from the real cash in my account. So I'd like to build a custom sizer that does exactly the same, but sizing on a percentage of Value instead of cash. This is what I tried, without success.

class ValuePercentSizer(bt.Sizer):
    params = (
        ('percents', 20),
        ('retint', True),
    )
    def __init__(self):
        pass

    def _getsizing(self, comminfo, value, data, isbuy):
        position = self.broker.getposition(data)
        if not position:
            size = value / data.close[0] * (self.params.percents / 100)
        else:
            size = position.size

        if self.p.retint:
            size = int(size)

        return size

[chrix]

@chrix I solved it like this

class ValuePercentSizer(bt.Sizer):
    params = (
        ('percents', 20),
        ('retint', True),# return an int size or rather the float value
    )

    def __init__(self):
        pass

    def _getsizing(self, comminfo, cash, data, isbuy):
        position = self.broker.getposition(data)
        accvalue = self.broker.getvalue()
        if not position:
            size = accvalue / data.close[0] * (self.params.percents / 100)
        else:
            size = position.size

        if self.p.retint:
            size = int(size)

        return size