Struct ResidualGate 

pub struct ResidualGate {
    pub gates: Vec<f32>,
}

Per-loop residual scaling gate. h^(τ) = h̃^(τ) + ρ_τ ⊙ h^(τ-1) Zero-init so first iteration is h̃^(1) (no residual from “previous”).

Fields

gates: Vec<f32>

Per-loop gates: [loop_count, dim]. Each ρ_τ is element-wise, zero-init.

Implementations

impl ResidualGate

pub fn new(loop_count: usize, dim: usize) -> Self

Allocate zeroed residual gates.

pub fn new_loop_stable(loop_count: usize, dim: usize, decay: f32) -> Self

Deterministic loop-stable residual gates (Plan 483 T2.1, §3.5 path 2).

Sets gates to a constant decay factor for τ > 0, enabling information carry-forward between T passes. The first loop (τ=0) has zero gates (no previous state to carry forward).

This is a modelless construction — no training, no gradient descent. The decay factor controls the trade-off between carry-forward strength and stability. Conservative values (0.1–0.3) are safe for most weight matrices; larger values risk divergence.

Rationale: the zero-init default (new()) makes every T-pass effectively independent — no hidden state carries forward between loops. This undermines the LT2 paper’s “effective depth T×n_layer” claim. A non-zero deterministic gate restores the residual connection across loops without requiring trained gate parameters.

Arguments

• loop_count - Number of T-passes (T)
• dim - Hidden dimension (n_embd)
• decay - Constant gate value for τ > 0 (e.g., 0.1 = conservative)

pub fn new_loop_stable_exp_decay( loop_count: usize, dim: usize, base: f32, ) -> Self

Deterministic loop-stable residual gates with exponential decay (Plan 483 T2.1, §3.5 path 2 variant).

ρ_τ = base^(τ-1) for τ > 0 — later loops contribute exponentially less. This schedule mirrors the spectral-radius-based stabilization where the residual contribution decays as the hidden state converges.

Arguments

• loop_count - Number of T-passes (T)
• dim - Hidden dimension (n_embd)
• base - Decay base (e.g., 0.5 → ρ_1=1.0, ρ_2=0.5, ρ_3=0.25, …)

Trait Implementations

impl Clone for ResidualGate

fn clone(&self) -> ResidualGate

Returns a duplicate of the value.

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

Performs copy-assignment from source.