Struct Options 

pub struct Options {
    pub tol: f64,
    pub scale: i32,
    pub btf: bool,
    pub halt_if_singular: bool,
}

Fixed solver configuration, mirroring the specific KLU_common fields sparse_klu.rs::new_common() (via klu_defaults) leaves at their defaults — confirmed directly from KLU/Source/klu_defaults.c — and that this port’s algorithm actually consumes. Kept as a struct (not bare constants) so differential tests (#[cfg(all(test, feature = "klu"))], comparing against the vendored C oracle) can vary tol/scale without touching any production code path, which always uses Options::default().

Two KLU_common fields are deliberately absent here, not just defaulted, because gridoxide’s call pattern makes the alternative branches they’d select genuinely unreachable (confirmed dead, not merely unused):

• ordering: real KLU supports AMD (0), COLAMD (1), user-supplied P/Q (2), or a user callback (3). klu_defaults.c defaults to 0 (AMD) and sparse_klu.rs never overrides it, so this port only ever implements the AMD path — no ordering field exists to accidentally select another one.
• maxwork: bounds the work btf_maxtrans may spend before giving up with a possibly-incomplete matching. Defaults to 0 (“no limit”) and is never overridden, so this port’s BTF implementation always runs btf_maxtrans to completion — the work-limit bookkeeping threaded through the upstream C is dropped outright, not merely defaulted off.

Fields

tol: f64

Partial-pivoting threshold: a candidate pivot is accepted only if its magnitude is at least tol times the largest candidate available in that column (otherwise the largest is forced instead). klu_defaults.c: Common->tol = 0.001.

scale: i32

Row-scaling strategy: 1 = sum of absolute values per row, 2 = max absolute value per row. klu_defaults.c: Common->scale = 2.

btf: bool

Whether to BTF-preorder before per-block AMD ordering. klu_defaults.c: Common->btf = TRUE. gridoxide never disables this, but it’s kept as a field (rather than assumed) so analyze phase tests can exercise the single-block (btf: false) path too.

halt_if_singular: bool

Abort immediately (and report singular) on a pivot that’s still zero after the tolerance-based search, rather than substituting a tiny nonzero value and continuing. klu_defaults.c: Common->halt_if_singular = TRUE.

Trait Implementations

impl Clone for Options

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Options

impl Debug for Options

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Options

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for Options

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Options