tud_lbm.operators.differential

Differential operators — composite builder and primitives.

Public API: build_diff_ops()

Implementation modules are internal; use the factory to access.

Example

from operators.differential import build_diff_ops

gradient_standard, gradient, laplacian = build_diff_ops(config, mp_params, lattice)

Functions

build_differential_fn(...)

Return a differential operator satisfying DifferentialOperator protocol.

build_diff_ops(→ tuple[collections.abc.Callable, ...)

Build gradient/laplacian closures, wetting-aware if applicable.

Package Contents

tud_lbm.operators.differential.build_differential_fn(scheme: str) → tud_lbm.operators.protocols.DifferentialOperator[source]

Return a differential operator satisfying DifferentialOperator protocol.

Parameters:

scheme – Differential operator name.

Returns:

A callable satisfying the DifferentialOperator protocol.

Raises:

ValueError – If scheme is not registered.

tud_lbm.operators.differential.build_diff_ops(config: tud_lbm.config.simulation_config.SimulationConfig, mp_params: tud_lbm.operators.macroscopic.MultiphaseParams | None, lattice: tud_lbm.lattice.lattice.Lattice) → tuple[collections.abc.Callable, collections.abc.Callable, collections.abc.Callable, collections.abc.Callable | None, collections.abc.Callable | None][source]

Build gradient/laplacian closures, wetting-aware if applicable.

Ensures boundary-condition modules are imported so that their @boundary_condition decorators have fired before we query pad-edge-mode metadata.

Returns five items:

  • gradient_standard: (grid) → result. Standard gradient ∇μ.

  • gradient_density: Density gradient ∇ρ, used in source terms.

  • laplacian_density: Laplacian ∇²ρ, used in chemical potential.

  • gradient_density_wetting: Parametric density gradient (grid, phi_l, phi_r, d_rho_l, d_rho_r) → result. None unless hysteresis is configured.

  • laplacian_density_wetting: Parametric Laplacian (grid, phi_l, phi_r, d_rho_l, d_rho_r) → result. None unless hysteresis is configured.

Design:

  • Non-wetting: All returned closures accept only (grid). gradient_density_wetting and laplacian_density_wetting are None.

  • Fixed wetting (wetting config but no hysteresis): Same behavior as non-wetting. gradient_density and laplacian_density close over static wetting parameters. gradient_density_wetting and laplacian_density_wetting are None.

  • Hysteresis: gradient_density and laplacian_density are initial closures seeded with wetting parameters (explicit or neutral defaults). gradient_density_wetting and laplacian_density_wetting are the parametric factories used by the hysteresis optimizer to build trial-step operators.

Parameters:

  • config – Validated simulation configuration.

  • mp_params – Multiphase parameters (None for single-phase).

  • lattice – The simulation Lattice (weights, velocities).

Returns:

(gradient_standard, gradient_density, laplacian_density, gradient_density_wetting, laplacian_density_wetting)