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Effect of training-history length

Walk-forward CV on the same 8 folds as the model comparison. Each configuration caps the training windows with make_data_op(max_train_rows=N), so only the amount of history used for fitting changes; test dates are identical. Metrics are pooled over all folds. TabICL uses eight estimators and its median prediction for MAPE.

"all" means no cap: each fold uses all data since 2021-03, about 26–47 months depending on the fold, so it has no single months value and is shown in the tables but not on the month axis. Training-history values are exact months (rows / 730.5 hours per month).

HGB mean (point forecast)

Training historyMAPE 1hMAPE 12hMAPE 24hMAPE averageMean fit time / fold
2.957 mo4.51%7.37%7.60%6.49%10.4 s
11.992 mo1.27%2.38%2.42%2.02%21.6 s
23.984 mo1.15%2.10%2.17%1.81%25.7 s
35.975 mo1.11%1.95%2.01%1.69%30.9 s
all1.11%1.92%1.99%1.67%33.0 s

TabICL (median forecast)

Training historyMAPE 1hMAPE 12hMAPE 24hMAPE averageTotal inference time
2.957 mo2.92%6.05%6.18%5.05%63.0 s
11.992 mo0.89%2.25%2.54%1.90%164.2 s
23.984 mo0.83%2.04%2.34%1.74%307.7 s
35.975 mo0.79%2.07%2.14%1.67%422.7 s
all0.79%2.06%2.12%1.65%463.1 s

MAPE vs history by horizon

Predicted vs actual load

Plots show the last CV fold (2025-03-01 to 2025-05-31) so the curves stay readable; quality metrics above use all 8 folds.

HGB mean

TabICL