How to generate CrossAbove or CrossBelow signal

Usct

I am trying to test a logic/ strategy where
if price of instrument 1 crosses above a threshold (fixed value 1)
then enter long position in instrument 2
if price of instrument crosses below a threshold (fixed value 2)
then cover long position in instrument 2
I want to know how to write Cross_Above or Cross_Below signal.
In crossover.py there are two classes on upcross and belowcross, but not sure how to use them. Any help is appreciated. Thanks

backtrader

An early example which uses CrossOver is here:

https://www.backtrader.com/blog/posts/2015-07-26-commission-schemes/commission-schemes.html

Replacing it with CrossUp will only generate positive signals and replacing it with CrossDown will generate only negative signals.

The main page contains a SignalStrategy based approach which goes only long. In this case CrossOver is also used to use the positive signals as entry signals and the negative as exit signals.

    from datetime import datetime
    import backtrader as bt
    
    class SmaCross(bt.SignalStrategy):
        params = (('pfast', 10), ('pslow, 30'))
        def __init__(self):
            sma1, sma2 = bt.ind.SMA(period=self.p.pfast), bt.ind.SMA(period=self.p.pslow)
            self.signal_add(bt.SIGNAL_LONG, bt.ind.CrossOver(sma1, sma2))
    
    cerebro = bt.Cerebro()
    
    data = bt.feeds.YahooFinanceData(dataname='YHOO', fromdate=datetime(2011, 1, 1),
                                     todate=datetime(2012, 12, 31))
    cerebro.adddata(data)

    cerebro.addstrategy(SmaCross)
    cerebro.run()
    cerebro.plot()

There is a full sigsmacross extending that sample in the sources.

You could add to signals rather than 1:

For LONG: CrossUp
For exiting the LONG position: CrossDown

The kselrsi sample contains a usage of both CrossUp and CrossDown

https://github.com/mementum/backtrader/blob/master/samples/kselrsi/ksignal.py

In any case the best to see how they operate would be to simply add them to the code and see the signals plotted.

Usct

Thanks for the reply, I will test and post results soon