partial_dependence.png

def fig_partial_dependence(model, X_test: pd.DataFrame) -> None:
    """PDP + ICE for sofa_score and alter in a two-panel figure."""
    fig, axes = plt.subplots(1, 2, figsize=(11, 4))

    # PartialDependenceDisplay uses feature names if X is a DataFrame.
    # NOTE: use "linewidth", not the "lw" alias -- newer matplotlib raises
    # "Got both 'linewidth' and 'lw'" if PartialDependenceDisplay's internal
    # defaults and our kwargs use different aliases for the same property.
    display = PartialDependenceDisplay.from_estimator(
        model, X_test,
        features=["sofa_score", "alter"],
        kind="both",       # "average" = PDP only; "both" adds ICE lines
        subsample=80,
        random_state=SEED,
        ax=axes,
        line_kw={"color": PRIMARY, "linewidth": 2.0, "label": "PDP (Durchschnitt)"},
        ice_lines_kw={"color": SECONDARY, "alpha": 0.15, "linewidth": 0.6},
    )

    titles = ["SOFA-Score", "Alter (Jahre)"]
    for i, ax in enumerate(axes):
        ax.set_title(f"PDP & ICE: {titles[i]}")
        ax.set_ylabel("Vorhergesagtes Sterberisiko (Wahrsch.)")
        ax.set_xlabel(titles[i])

    fig.suptitle("Partial Dependence & ICE — globaler vs. individueller Effekt",
                 fontsize=12, fontweight="bold", y=1.02)
    fig.tight_layout()
    save(fig, ASSETS / "partial_dependence.png")