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Pulse and Local Prediction Error: An Event-Driven Substrate

A compute substrate where cells fire only when input change crosses a learned threshold, and learning is driven by local prediction error — no backward pass. Designed to run on commodity CPUs.

Authors: Er. Infant Nirmal Priyan
Pulse and Local Prediction Error: An Event-Driven Substrate
Indian Patent Application & Intellectual Property Disclosure

Invention: Event-Gated Sparse Computation with Self-Calibrating Surprise Thresholds (Pulse Substrate & LPE Rule).
Patent Office: Government of India — The Patents Act, 1970 & The Patents Rules, 2003 (Form 2 Provisional Specification).
Inventor & Applicant: Er. Infant Nirmal Priyan J, Adrient Pvt Ltd, Bangalore, Karnataka, India.

1. Abstract & Architecture Overview

Two fundamental costs dominate contemporary sequence modeling: the quadratic attention overhead over context length and the immense datacenter energy required for global backpropagation through time. Pulse introduces an event-driven recurrent substrate where computation is conditional on surprise: each dynamical unit updates its state only when input deviation from a learned running expectation exceeds a self-calibrating threshold.

Crucially, the exact same local prediction-error signal that gates computation also drives all synaptic learning. There is no global backward pass, no computational gradient graph, and no inter-module synchronization anywhere in the substrate.

2. Core Mathematical Formulations

Formula 1 — Event Gating Dynamics
surprise_i(t) = || x_i(t) - EMA_i(x) ||₁
EMA_i ← (1 - β)·EMA_i + β·x_i(t)   [β = 0.01]
fire_i(t) = (surprise_i(t) > θ_i)

A cell fires only when deviation from running expectation crosses threshold θ. Inactive cells consume zero computational operations.

Formula 2 — State Persistence & Sparsity
if fire: s_i(t) = tanh(W_in x_i(t) + Σ_j A_ij s_j(t-1) + b_i)
else:    s_i(t) = s_i(t-1)   [Zero Compute]

Unfired cells maintain their exact state without computing synaptic gathers, achieving 5× to 20× compute reductions on structured inputs.

Formula 3 — Self-Calibrating Threshold Update
θ_i ← θ_i + μ · ( |e_i(t)| - θ_i )

The threshold learns directly from local prediction error e_i. Compute gating, learning gating, and memory gating are unified in a single signal.

Formula 4 — Local Prediction Error (LPE) Plasticity
x̂_i(t+1) = P_i( s_i(t) ) + p0_i
e_i(t) = x_i(t+1) - x̂_i(t+1)
W_i ← W_i - η · e_i(t) · (∂x̂_i / ∂W_i)

Every cell predicts its own next input. Weight updates depend strictly on local pre- and post-synaptic variables with closed-form analytical shrinkage.

3. Multiply-Free Ternary Execution for Commodity CPUs

Following quantization-aware stabilization, substrate synaptic weights are constrained to the ternary set {-1, 0, +1}. Consequently, large-scale matrix-vector dot products transform into multiply-free addition and subtraction chains:

dot_product(W_ternary, x) = sum(x[pos_indices]) - sum(x[neg_indices])

Maps directly to SIMD integer instructions (AVX2, AVX-512, and ARM NEON) without requiring tensor processing units (TPUs) or high-wattage GPUs.

4. Empirical Validation & Experimental Proof

Evaluation Metric Empirical Result Baseline / Target Verification Reference
Deterministic Reproducibility 100 / 100 bit-exact matches ≥ 99% reproducibility g4_wave0::t5b
Gradient Match vs Finite Differences 10⁻¹⁵ relative error ≤ 10⁻⁸ numerical tolerance g4_wave1::t8_w_in_gradient
Synaptic Drift Stability ||ΔW_in|| = 48.8, ||ΔA|| = 0.295 Strictly bounded plasticity G4 Dense Integration
Event Compute Sparsity 5× to 20× FLOP reduction ≥ 3× reduction Pulse Native Engine