In addition to whatever factors I've set up, I'd like the assets in my context.portfolio.positions to pass the screening process as well, so I can monitor for changes in their factors too.
If I were to not screen anything (to make sure not accidentally filtering our assets away) and then grab them in before_trading_start, for example:
def before_trading_start(context, data):
context.output = pipeline_output('pipeline')
currentPositions = context.output.loc[context.portfolio.positions]
I would indeed be able to monitor the same factors, but without a screen we'll run into memory issues almost immediately.
I might be able to do something with fundamentals.company_reference.primary_symbol, but I'm not sure how to go about implementing that.