9.8. Fragility Functions from MCA

plotter.plot_fragility_from_mca(cloud_dict, imt_label, xlims, ylims, title=None, cloud_method=None, plot_bootstrap=False, pFlag=True, export_path=None)[source]

Generates a fragility analysis plot showing the Probability of Exceedance (PoE) for multiple damage states using Modified Cloud Analysis (MCA) results.

Supports both uncertainty quantification approaches:

  • 'bootstrap': plots the mean fragility curves and, optionally, individual bootstrap realizations as a faint background cloud.

  • 'classical': plots the Robust Fragility mean and a shaded ±k·σ confidence band derived from the posterior variance (Jalayer et al. 2017).

The cloud_method is auto-detected from cloud_dict['fragility']['cloud_method'] when the argument is None (default), falling back to 'bootstrap' for dicts produced by older code that does not carry the key.

The figure uses self.figsize with constrained_layout and is saved without bbox_inches='tight' so that every output image has identical, deterministic pixel dimensions.

Parameters:

  • cloud_dict (dict) –

    Standardized dictionary returned by postprocessor.process_mca_results(). Required keys:

    • 'fragility': contains intensities (1-D array), poes (2-D), medians, betas_total.

    • For 'bootstrap': 'bootstraps' sub-dict with alpha0, alpha1 arrays and optional poes_all (3-D array of per-iteration curves).

    • For 'classical': 'fragility' must also contain poes_robust_plus and poes_robust_minus; and 'mcmc' sub-dict with chi_mean.

  • imt_label (str) – X-axis label (e.g., 'PGA [g]', 'Sa(T1) [g]').

  • xlims (tuple of float) – (min, max) limits for the X-axis.

  • ylims (tuple of float) – (min, max) limits for the Y-axis.

  • title (str, optional) – Custom plot title. If None, a method-specific default is used.

  • cloud_method ({'bootstrap', 'classical'} or None, optional) – Selects the plotting style. When None (default), the value is read from cloud_dict['fragility'].get('cloud_method', 'bootstrap').

  • plot_bootstrap (bool, default False) – Bootstrap only. If True, plots all individual bootstrap fragility curves with low alpha as a background cloud. Ignored when cloud_method='classical'.

  • pFlag (bool, default True) – If True, renders and/or saves the figure. If False, closes the figure immediately (useful for batch runs).

  • export_path (str, optional) – Full file path (including extension) for saving the figure. The parent directory is created automatically if needed.

Return type:

None