Struct SparseAtomCodes 

pub struct SparseAtomCodes { /* private fields */ }

Storage for the per-row codes of all N observations.

Held column-of-structs rather than struct-of-columns: each row’s (active_mask, weights) lives together because the atom-selection strategies all touch a single row at a time. Cross-row vectorization happens through ndarray views built on demand.

Implementations

impl SparseAtomCodes

pub fn empty(n_obs: usize, k_atoms: usize) -> Self

Allocate n_obs empty codes, each sized for k_atoms.

pub fn n_obs(&self) -> usize

pub fn k_atoms(&self) -> usize

pub fn row(&self, n: usize) -> &SparseAtomCode

pub fn row_mut(&mut self, n: usize) -> &mut SparseAtomCode

pub fn iter(&self) -> impl Iterator<Item = &SparseAtomCode>

pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut SparseAtomCode>

pub fn weights_matrix(&self) -> Array2<f64>

Flatten weights into a single (N, K) array, with zeros where the mask is unset. Allocates; intended for diagnostic / post-fit use.

pub fn coactivation(&self, a: usize, b: usize) -> CoactivationStats

Co-activation statistics for one atom pair (a, b) — the #976 code-dependence trigger. Pure popcount ratios over the active masks: P(a|b) = #{rows: a∧b} / #{rows: b} and symmetrically.

Two derived readings drive the structure search:

• CoactivationStats::dependence (symmetric, the FUSION trigger) — independent atoms with marginal activation rates π_a, π_b co-activate at rate π_a·π_b, so both conditionals stay near the marginals; a shattered curved family re-encoded as several near-duplicate atoms pushes both conditionals toward 1.
• CoactivationStats::absorption_asymmetry (the ABSORPTION-audit trigger) — an A⇒B hierarchy where sparsity folded B’s content into A shows P(parent|child) ≈ 1 without the converse, so a large asymmetry with one conditional near 1 flags the pair for the within-atom substructure audit (#907 race on the atom’s own code distribution).

These are triggers, not decisions: they rank move proposals deterministically; acceptance is owned by the e-process gates in gam_solve::structure_search.

pub fn weight_codependence(&self, a: usize, b: usize) -> f64

#976 — the AMPLITUDE half of the fusion criterion: the Pearson correlation of the two atoms’ activation WEIGHTS over the rows where both are active. Support co-activation (CoactivationStats::dependence) only says the two atoms fire together; it cannot distinguish a single curved family SHATTERED across two near-duplicate atoms (where moving along the family smoothly trades amplitude between the pair, so their weights are strongly — typically negatively — correlated on the joint support) from two GENUINELY INDEPENDENT atoms that merely happen to co-fire on the same input class (weights uncorrelated). The magnitude |ρ| of this correlation is the interaction-evidence the issue’s fusion trigger pairs with code dependence: high support-overlap AND high |weight_correlation| is the shattering signature (“dependent codes + joint interaction evidence”), whereas high overlap with |ρ|≈0 is two independent features that should NOT be fused.

Returns 0.0 when fewer than two rows are jointly active or when either atom’s weight is constant on the joint support (an undefined correlation is, for the trigger, “no amplitude dependence detected”).

Trait Implementations

impl Clone for SparseAtomCodes

fn clone(&self) -> SparseAtomCodes

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SparseAtomCodes

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

Formats the value using the given formatter.