Struct BoundedState 

pub struct BoundedState {
    pub window: usize,
    pub num_kv_heads: usize,
    pub head_dim: usize,
    pub ring_k: Vec<f32>,
    pub ring_v: Vec<f32>,
    pub seen: usize,
    /* private fields */
}

Per-layer bounded state: the ring of the last W raw keys/values per KV head plus the insert counter. len = min(seen, W), next write slot head = seen mod W, and the key of position j lives in slot j mod W — so no absolute position is ever stored.

Fields

window: usize

num_kv_heads: usize

head_dim: usize

ring_k: Vec<f32>

[kvh][W][hd], raw (unrotated) keys.

ring_v: Vec<f32>

[kvh][W][hd].

seen: usize

Tokens inserted since the last clear (= the next position).

Implementations

impl BoundedState

pub fn new(num_kv_heads: usize, head_dim: usize, window: usize) -> Self

pub fn len(&self) -> usize

Filled slots, min(seen, W).

pub fn is_empty(&self) -> bool

pub fn head(&self) -> usize

Next write slot, seen mod W.

pub fn state_bytes(&self) -> usize

Bytes of the wire-visible state (ring + counter). The undo rows are scratch of fixed size and are not state.

pub fn clear(&mut self)

Zero the record (fresh sequence). Capacity never changes.

pub fn insert(&mut self, k: &[f32], v: &[f32])

Write k, v ([kvh][hd], raw) into slot seen mod W, saving the overwritten rows for rollback.

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

Undo the last n inserts exactly (restores the overwritten slots). Returns how many were rolled back — fewer than n only when the rollback history (UNDO_DEPTH) or the inserted count is shorter.

pub fn snapshot(&self) -> BoundedSnapshot

pub fn restore(&mut self, s: &BoundedSnapshot)

Restore a snapshot taken on THIS state (same geometry). The undo history is discarded: it described inserts that no longer exist.

pub fn same_state(&self, other: &BoundedState) -> bool

Bit-for-bit equality of the wire-visible state.

pub fn attend( &self, q: &[f32], num_heads: usize, sink_k: &[f32], sink_v: &[f32], sink: usize, rope: &BoundedRope, scale: f32, out: &mut [f32], )

Attend every Q head of every KV group over sink ∪ window and write [nh][hd] into out. q is [nh][hd] RAW (unrotated); the current token must already be inserted (the window includes it, matching the trainer’s band col == S + row).

Trait Implementations

impl Clone for BoundedState

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for BoundedState

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

Formats the value using the given formatter.