Boundary-condition recipes

Owner: linstabpy.boundary_conditions.recipe.

BCRecipe is the seam. Public YAML files pass lists of dictionaries. The recipe layer normalizes them before application.

Rules

BCRule.from_mapping validates type, borders, and variables. Overlap resolution picks the effective rows owned by the last matching rule. Column-zeroed Dirichlet rows are the broader set needed for operator reduction and provenance.

When you change boundary-condition behavior, update the recipe analysis and every backend wrapper together. Do not duplicate row-selection logic in assembly, runtime code, or example scripts.

Dispatch

Method	Backend
apply_to	SciPy CSC temporal operator
apply_to_petsc	PETSc Mat
apply_to_spatial	SciPy spatial pair (Lc, R)
apply_to_spatial_petsc	PETSc spatial pair
analyze	Index sets only, no matrix write

Dirichlet implementation: boundary_conditions.dirichlet (penalty plus column zeroing). Neumann: boundary_conditions.neumann.