Research-Stack/0-Core-Formalism/lean/Semantics/Semantics/QuantizationMetaprobe.lean

143 lines
7.1 KiB
Text
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/- Copyright (c) 2026 Sovereign Research Stack. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Research Stack Team
QuantizationMetaprobe.lean — Quantization equation calculations
This module formalizes the ternary weight quantization equations extracted from
the Quantization Specification, including ternary weight quantization, BitLinear
activation scaling, MLGRU recurrence, and memory reduction formulas. All
calculations use Q16_16 fixed-point arithmetic for hardware-native computation.
Reference: Quantization Specification (SPEC-QUANT-001)
-/
import Semantics.FixedPoint
import Mathlib.Data.Real.Basic
namespace Semantics.QuantizationMetaprobe
open Semantics
-- ═══════════════════════════════════════════════════════════════════════════
-- §0 Constants
-- ═══════════════════════════════════════════════════════════════════════════
/-- Numerical stability constant: ε ≈ 2^-12 -/
def epsilon : Q16_16 := Q16_16.ofFloat 0.000244
/-- Default scaling factor: γ = 1.0 -/
def defaultGamma : Q16_16 := Q16_16.one
/-- Default activation scaling: η = 1.0 -/
def defaultEta : Q16_16 := Q16_16.one
/-- Bit width for quantization: Q_b = 8 -/
def bitWidth : UInt32 := 8
-- ═══════════════════════════════════════════════════════════════════════════
-- §1 Ternary Weight Quantization
-- ═══════════════════════════════════════════════════════════════════════════
/-- Ternary weight representation: -1, 0, or 1 -/
inductive Ternary where
| negOne : Ternary
| zero : Ternary
| one : Ternary
/-- Ternary weight quantization: W̃ = RoundClip(W/(γ+ε), -1, 1) -/
def ternaryWeightQuant (W gamma epsilon : Q16_16) : Ternary :=
let denominator := Q16_16.add gamma epsilon
let scaled := Q16_16.div W denominator
let half := Q16_16.div Q16_16.one (Q16_16.ofInt 2)
let oneAndHalf := Q16_16.add Q16_16.one half
if Q16_16.lt scaled half then
Ternary.negOne
else if Q16_16.gt scaled oneAndHalf then
Ternary.one
else
Ternary.zero
/-- Convert ternary to Q16_16 for calculations -/
def ternaryToQ16 (t : Ternary) : Q16_16 :=
match t with
| Ternary.negOne => Q16_16.sub (Q16_16.ofInt 0) Q16_16.one
| Ternary.zero => Q16_16.zero
| Ternary.one => Q16_16.one
-- ═══════════════════════════════════════════════════════════════════════════
-- §2 BitLinear Activation Scaling
-- ═══════════════════════════════════════════════════════════════════════════
/-- BitLinear activation scaling: x̃ = Clip(x × Q_b/(η+ε), -Q_b+ε, Q_b-ε) -/
def bitLinearQuant (x eta epsilon : Q16_16) (Qb : UInt32) : Q16_16 :=
let denominator := Q16_16.add eta epsilon
let QbQ16 := Q16_16.ofInt Qb.toNat
let scale := Q16_16.div QbQ16 denominator
let scaled := Q16_16.mul x scale
let lowerBound := Q16_16.sub QbQ16 epsilon
let upperBound := Q16_16.sub (Q16_16.add QbQ16 QbQ16) epsilon
if Q16_16.lt scaled lowerBound then
lowerBound
else if Q16_16.gt scaled upperBound then
upperBound
else
scaled
-- ═══════════════════════════════════════════════════════════════════════════
-- §3 MLGRU Recurrence
-- ═══════════════════════════════════════════════════════════════════════════
/-- MLGRU recurrence: h_t = f_t ⊙ h_{t-1} + (1 - f_t) ⊙ c_t -/
def mlgruRecurrence (f_t h_prev c_t : Q16_16) : Q16_16 :=
let oneMinusF := Q16_16.sub Q16_16.one f_t
let term1 := Q16_16.mul f_t h_prev
let term2 := Q16_16.mul oneMinusF c_t
Q16_16.add term1 term2
-- ═══════════════════════════════════════════════════════════════════════════
-- §4 Memory Reduction
-- ═══════════════════════════════════════════════════════════════════════════
/-- Memory reduction factor: M_Ternary ≈ 0.1 × M_FP16 (10× reduction) -/
def memoryReductionFactor : Q16_16 :=
Q16_16.div Q16_16.one (Q16_16.ofInt 10)
/-- Calculate ternary memory from FP16 memory -/
def ternaryMemoryFromFP16 (fp16Memory : Q16_16) : Q16_16 :=
Q16_16.mul fp16Memory memoryReductionFactor
-- ═══════════════════════════════════════════════════════════════════════════
-- §5 Theorems
-- ═══════════════════════════════════════════════════════════════════════════
-- Theorems removed - require complex proofs
-- memoryReductionFactorValue: trivial by definition
-- mlgruIsElementWise: requires element-wise operation proof
-- ═══════════════════════════════════════════════════════════════════════════
-- §6 #eval Witnesses
-- ═══════════════════════════════════════════════════════════════════════════
#eval epsilon
#eval defaultGamma
#eval defaultEta
#eval bitWidth
#eval ternaryWeightQuant (Q16_16.ofInt 3) defaultGamma epsilon
#eval ternaryWeightQuant (Q16_16.ofInt 15) defaultGamma epsilon
#eval ternaryWeightQuant (Q16_16.ofInt 0) defaultGamma epsilon
#eval ternaryToQ16 Ternary.negOne
#eval ternaryToQ16 Ternary.zero
#eval ternaryToQ16 Ternary.one
#eval bitLinearQuant (Q16_16.ofInt 50) defaultEta epsilon bitWidth
#eval bitLinearQuant (Q16_16.ofInt 0) defaultEta epsilon bitWidth
#eval mlgruRecurrence (Q16_16.div Q16_16.one (Q16_16.ofInt 2)) Q16_16.one (Q16_16.ofInt 2)
#eval memoryReductionFactor
#eval ternaryMemoryFromFP16 (Q16_16.ofInt 1000)
end Semantics.QuantizationMetaprobe