Finite-volume diffusion solves¶

The functions below execute Morana’s cell-centered finite-volume diffusion method. Pass a complete ProblemConfiguration or ProblemConfigurationSnapshot explicitly to each function. A mutable configuration is captured as an immutable snapshot at solve entry; a supplied snapshot is used directly. The completed result retains that same snapshot as provenance.

finite_volume ¶

Finite-volume multigroup diffusion solve entry points.

solve_fixed_source ¶

solve_fixed_source(
    configuration: (
        ProblemConfiguration | ProblemConfigurationSnapshot
    ),
    settings: FixedSourceSettings | None = None,
) -> Result

Solve the layered multigroup hex-z fixed-source problem.

The optional configured volumetric source and additive boundary terms form the right-hand side. The solver applies the configured direct or GMRES policy to the coupled loss-minus-fission system, accepts only negative flux roundoff within flux_nonnegativity_tolerance, and checks the relative linear residual against settings.linear_solve’s relative-residual tolerance. The completed result has keff=None and one linear-solve report. A mutable configuration is snapshotted at entry; a supplied snapshot is retained directly as result provenance. Calculation uses that immutable snapshot directly.

Parameters:

Name	Type	Description	Default
`configuration`	`ProblemConfiguration \| ProblemConfigurationSnapshot`	Mutable problem definition or immutable snapshot to solve.	required
`settings`	`FixedSourceSettings \| None`	Immutable fixed-source controls. `None` creates default `FixedSourceSettings` for this call only.	`None`

Returns:

Type	Description
`Result`	Completed flux, balance, convergence, and provenance data.

Raises:

Type	Description
`TypeError`	If configuration is neither `ProblemConfiguration` nor `ProblemConfigurationSnapshot`, or settings are not `FixedSourceSettings` or `None`.
`ValueError`	If the active domain, material data, boundary coverage, or configured source is invalid; a linear system or preconditioner is unusable; or flux and residual numerical checks fail.

solve_keff ¶

solve_keff(
    configuration: (
        ProblemConfiguration | ProblemConfigurationSnapshot
    ),
    normalization: (
        FissionSourceNormalization | PowerNormalization
    ),
    settings: KeffSettings | None = None,
) -> Result

Solve a physically normalized fission eigenvalue diffusion problem.

A configured positive fission-source rate or recoverable thermal-power target scales the exposed result after convergence; it does not alter the returned keff. Power normalization requires kappa_sigma_f for every fissionable active material. The solver verifies that requirement before it assembles finite-volume operators or prepares an inner linear solve. The solver starts from a positive unit-fission-source vector, then requires all three effective convergence criteria—multiplication-factor change, volume-weighted flux change, and relative eigenvalue-equation residual—to meet their explicit tolerances within max_outer_iterations. A mutable configuration is snapshotted at entry; a supplied snapshot is retained directly as result provenance. Calculation uses that immutable snapshot directly.

Parameters:

Name	Type	Description	Default
`configuration`	`ProblemConfiguration \| ProblemConfigurationSnapshot`	Mutable problem definition or immutable snapshot to solve.	required
`normalization`	`FissionSourceNormalization \| PowerNormalization`	Immutable target fission-neutron source rate or recoverable thermal power for the completed result.	required
`settings`	`KeffSettings \| None`	Optional immutable criticality numerical controls. `None` uses default `KeffSettings` for this call only.	`None`

Returns:

Type	Description
`Result`	Completed physically normalized flux, multiplication factor, balance, convergence, and provenance data.

Raises:

Type	Description
`TypeError`	If configuration is neither `ProblemConfiguration` nor `ProblemConfigurationSnapshot`, normalization is neither `FissionSourceNormalization` nor `PowerNormalization`, or settings are neither `KeffSettings` nor `None`.
`ValueError`	If an independent source is configured; the active domain, material data, fission production, power data, or exposed boundary data is ineligible; the loss matrix is singular; or an inner solve, flux, or residual fails numerical checking.
`RuntimeError`	If power iteration does not satisfy all three convergence criteria within `settings.max_outer_iterations`.