matflow.subset_simulation.subset_simulation.weakest_link_performance_coarse

matflow.subset_simulation.subset_simulation.weakest_link_performance_coarse(x, y_star, group_idx)

‘Coarse mesh’ weakest-link performance: as weakest_link_performance_fine, but evaluated on a block-averaged (coarser-voxelised) version of the field. Averaging smooths out sub-block fluctuations, so the coarse peak response never exceeds the fine one (max(block_average(x)) <= max(x), by convexity of the mean) – exactly mirroring how a coarser FE mesh smooths out local stress/strain concentrations relative to a finer one. This guarantees the coarse model can only underestimate peak failure severity relative to the fine model, never overestimate it, so estimate_conservative_threshold_coarse’s margin is always well-defined and finite (no risk of unbounded extrapolation error, unlike a curve-fit surrogate).