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smh | 1 year ago

You are using 32 bit floats to represent money?

Does your project correctly calculate $300,000.00 + $0.01, (or even just correctly represent the value $300,000.01) and if so, how?

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nurettin|1 year ago

Obviously you can't accumulate cent by cent. You can't even safely accumulate by quarter. Epsilon is too large to do that. I calculate cumulative pnl using std::fma, then multiply AUM with that and round to cents. It's good enough for backtesting, and it shaves a bunch of seconds off the clock.

smh|1 year ago

I see - I guess it's a financial modelling program or similar where the quantities don't represent precise values of money. I was imagining some kind of accounting-like app that would need to be reconciled with real-world balances.