Struct MinDegree 

pub struct MinDegree;

Minimum-degree metric — the AMD selection rule of Amestoy, Davis, Duff (1996).

Score is the running degree. Bucket index is the score itself. All buckets are “fine” (head-only pivot selection). Supervariable merge does not update the score (AMD tracks degree only via nv[i] and the per-iteration Pass-2 monotone cap).

Trait Implementations

impl Clone for MinDegree

fn clone(&self) -> MinDegree

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MinDegree

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

Formats the value using the given formatter.

impl Default for MinDegree

fn default() -> MinDegree

Returns the “default value” for a type.

impl Metric for MinDegree

type Score = i32

Bucket key produced by the selection metric. AMD uses i32 (the running degree); AMF will also use i32 (quantized RMF).

fn n_buckets(n: usize) -> usize

Length of the bucket head array Workspace::head. AMD: n (indexed up to n - 1 by select_pivot’s while deg < n). AMF: 2 * n + 2.

fn init_score(len: i32) -> i32

Initial score for a freshly-loaded variable with adjacency length len. AMD and AMF both seed len.

fn bucket(score: i32, _n: usize) -> usize

Bucket index for the given score. AMD: identity. AMF: identity for s ≤ n, coarse-stride above.

fn coarse_bucket(_idx: usize, _n: usize) -> bool

Whether idx falls in the “coarse” bucket region — i.e. select_pivot must linear-scan the bucket chain to pick the minimum-score entry, rather than just taking the head. AMD always returns false; AMF returns idx > n.

fn merge_supervariable(_parent: &mut i32, _child: i32)

Update parent’s score on supervariable merge of child into parent. AMD: no-op. AMF: *parent = max(*parent, child).

fn run_elimination( ws: &mut Workspace, aggressive: bool, ) -> Result<StepFlops, OrderingError>

Run the metric’s elimination loop on a freshly initialised Workspace. Returns the accumulated flop counters.

impl Copy for MinDegree