grid_convergence
Estimate mesh discretization error: give the same solved quantity on 2–3 refined meshes to fit the observed order of convergence and return the Richardson-extrapolated GCI confidence band.
Instructions
Grid Convergence Index — how much of a solved number is the MESH (no solver, milliseconds). Give it the same quantity solved on 2-3 systematically refined meshes, FINEST FIRST, and it fits the observed order of convergence, Richardson-extrapolates to zero cell size, and returns the percentage band inside which the mesh-independent answer lies. Roache's GCI as codified in ASME V&V 20.
This is the honest band_pct for a result with no analytic oracle — the
verification counterpart to every validation ratio in the solver families — and it
is deliberately family-agnostic: three CFD drag coefficients, three FEM peak
stresses and three modal frequencies are all valid input; only you know what the
mesh size means. cfd_mesh_independence_submit is the driver that produces the
three CFD values for you.
Describe the meshes with either cell_sizes (representative cell length, same
order as values) or cell_counts (total cells; h = N^(-1/dimensions)). With
THREE values the order is measured and the safety factor is 1.25; with TWO it must
be assumed (assumed_order, default 2.0) and the factor triples to 3.0 — a much
wider band, which is the honest price of the missing mesh.
Watch three fields before quoting the band: monotonic False means the solutions
oscillate and the extrapolation is not meaningful (usually an unconverged level,
not a mesh effect); asymptotic_ratio far from 1 means the meshes have not reached
the range where the theory holds, so gci_pct is a LOWER bound; order_clamped
True means the fitted order was unphysical and a clamped one was used.
Returns {n_levels, values, cell_sizes, refinement_ratios, observed_order, order_used, order_clamped, extrapolated_value, gci_pct, gci_coarse_pct, band_pct, relative_error_pct, monotonic, asymptotic_ratio, safety_factor, converged_fit, fidelity, warnings}.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| values | Yes | ||
| cell_sizes | No | ||
| dimensions | No | ||
| cell_counts | No | ||
| assumed_order | No |