Struct LayerKvCache 

pub struct LayerKvCache {
    pub mode: KvMode,
    pub seq_len: usize,
    pub num_kv_heads: usize,
    pub head_dim: usize,
    pub linear_state: Vec<f32>,
    pub linear_scratch: Vec<f32>,
    pub o1: Option<O1State>,
    /* private fields */
}

KV cache for a single layer, head-major.

Fields

mode: KvMode

seq_len: usize

Positions appended so far (grows once per token, dead heads included).

num_kv_heads: usize

head_dim: usize

linear_state: Vec<f32>

Linear-core condensate S (vmf_phase), f64; empty on full layers.

linear_scratch: Vec<f32>

Tentative lane-2 state during speculative verify.

o1: Option<O1State>

O(1) Nyström override (None = plain cache attention).

Implementations

impl LayerKvCache

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

pub fn o1_begin(&mut self, m: usize, w: usize, sink: usize, rect: O1Rect)

Arm query collection for a fresh prompt pass (a cleared cache).

pub fn o1_push_q(&mut self, q_all: &[f32])

Record one position’s rotated queries ([num_heads × head_dim]) during the exact prompt pass. No-op unless collecting — the hook sits inside qwen_attention so every prefill flavor (sequential, batched) feeds the same trace.

pub fn o1_sealed(&self) -> bool

pub fn o1_seal(&mut self, num_heads: usize) -> bool

Freeze the prompt into per-KV-group Nyström states and drop this layer’s full KV. Returns false (layer stays exact, KV kept) when the preconditions fail: the seal needs f32 KV rows (CMF_KV=q8 stores int8), every group densely stored, a full q trace, and a GQA fan-out that actually divides.

pub fn o1_step( &mut self, q_all: &[f32], k_new: &[f32], v_new: &[f32], num_heads: usize, ) -> Vec<f32>

One decode step on a sealed layer: per KV group, insert the group’s fresh (k, v) ONCE and read every Q head’s attention output. Returns [num_heads × head_dim]. Head h belongs to group h/hpk, so a group’s Q heads are contiguous in q_all/out — same math as the shared KV row the exact path appends once.

pub fn o1_memory_bytes(&self) -> usize

Bytes held by the O(1) override (query trace while collecting, per-KV-group states once sealed).

pub fn append(&mut self, k_new: &[f32], v_new: &[f32], alive: &[bool])

Append K/V for one position. k_new/v_new are [num_kv_heads × head_dim]; heads with alive[h] == false are skipped (their slices stay empty).

pub fn attend(&self, q: &[f32], kv_head: usize) -> (Vec<f32>, Vec<f32>)

Per-head attention over its own storage: the f32 branch is bit-for-bit equal to attention_head() over slices; the q8 branch computes score = s_k·⟨q⊙col_k, k_q⟩ and the weighted sum of V in i8 with f32 accumulation. Returns (output [head_dim], probs [stored]).

pub fn attend_group( &self, q_group: &[f32], kv_head: usize, out: &mut [f32], imp_acc: &mut [f32], scale: f32, first: usize, )

Grouped GQA attention: all Q-heads of one KV group in a single pass over the stored K rows and a single pass over the V rows (per-head attend re-read the shared group storage heads_per_kv times — roadmap §3 P1). Per-head score order, softmax and V accumulation are IDENTICAL to attend, so each head’s output is bit-for-bit the same.

q_group: [n_heads_in_group × head_dim] (global head order); out: same shape; imp_acc[0..stored] accumulates the probs of every head (Born importance), matching the caller’s former loop. scale is the score scale (1/√hd unless the arch overrides); first is the earliest visible position — sliding-window layers pass stored − window so older rows get zero probability.

pub fn truncate_last(&mut self, n_drop: usize)

Roll back the last n_drop positions (speculative-decode reject).

pub fn accumulate_imp(&mut self, probs: &[f32])

Accumulate attention mass per stored position (summed over heads).

pub fn head_keys(&self, kv_head: usize) -> &[f32]

Contiguous keys of one head: [stored_len × head_dim].

pub fn head_values(&self, kv_head: usize) -> &[f32]

pub fn head_len(&self, kv_head: usize) -> usize

Number of positions actually stored for a head (0 for dead heads).

pub fn clear(&mut self)

Clear cache (e.g. on new conversation or task switch).

pub fn memory_bytes(&self) -> usize

Memory usage in bytes.

Trait Implementations

impl Clone for LayerKvCache

fn clone(&self) -> LayerKvCache

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LayerKvCache

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

Formats the value using the given formatter.