covariance_window days used as warmup. With ML/DL you still think in start + end of the sample — not a three-ended train / mid / test calendar.
Common paths
Quick backtest — you care about weights and historical performance, not machine learning:Mixing and matching
A few patterns people use often:- Same data, many portfolios — download prices once, then try equal weight, HRP, max Sharpe, DCC, and so on side by side.
- Backtest, then dig in — after a run, ask for an equity curve, weight paths, or a risk report without starting from scratch.
- Your book, QuantLab analytics — paste holdings and ask how bad tomorrow looks under a shock, or whether something looks overweight versus optimized alternatives.
- With or without ML — skip models when you only need classical portfolio math; add XGBoost, LightGBM, CatBoost, or a neural net when forecasts matter.