Developing Own pnl & pnlcomm calculation

[Michael Scofield]

Hi all. I want to ask how to develop my own pnl & pnlcomm calculation. Should I inheritance the Trade class and override the "update" method, or there is other way to do so? And after I developed my own calculation how to apply this to the platform?
Please give me some hints, thank you!

[backtrader]

The calculation of profit/loss and commissions is not in the Trade. This simply uses the reported values to update itself.

How profit/loss and comissions are calculated is controlled by commission schemes. You can supply your own (for all assets or for assets individually) See

• Commissions: Stocks vs Futures
• Extending Commissions
• User Defined Commissions

See also this independent blog:

• Backtest Rookies - Code Snippet: Stamp Duty Commission Scheme

[Richard O'Regan]

Hi backtrader, I'm just reading docs/code to understand your answer to Michael as I have similar question.. I think this is correct.

Ok, so the code he'd need to override is here:

I'd like to use R multiples in the pnl instead or raw values. ( If this needs a separate post let me know. But I'm guessing I'd be in the same boat as Micheal?)
Thanks for all your dedication.

[Michael Scofield]

Thank you guys @Richard O'Regan @backtrader !

[backtrader]

Yes, that would be it. You later add it with: addcommissioninfo(comminfo, name) where name defaults to None to be the default for all assets.

If the name matches the name of an asset it will be specifically applied to that asset.

See: Docs - Broker for the reference

[Richard O'Regan]

@backtrader ahh got it, thanks for adding that. @Michael-Scofield no problem mate:)