Research-Stack/2-Search-Space/PIST/TorsionalPIST.lean

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import Semantics.Quaternion
import Semantics.Adaptation
import Semantics.FixedPoint
import Semantics.DynamicCanal
namespace Semantics.TorsionalPIST
open DynamicCanal
open Semantics.Quaternion
/-- Implementation of the PIST tile as a Torsional state. -/
structure TorsionalState where
q1 : Semantics.Quaternion.Quaternion
q2 : Semantics.Quaternion.Quaternion
q3 : Semantics.Quaternion.Quaternion
eta : DynamicCanal.Fix16
energy : DynamicCanal.Fix16
deriving Repr, DecidableEq, Inhabited
def TorsionalState_initial : TorsionalState :=
{ q1 := Semantics.Quaternion.Quaternion.one
, q2 := Semantics.Quaternion.Quaternion.one
, q3 := Semantics.Quaternion.Quaternion.one
, eta := { raw := 0x00010000 }
, energy := { raw := 0 } }
def TorsionalState_torsionalBetaStep (s : TorsionalState) (dt : DynamicCanal.Fix16) : TorsionalState :=
let target := Semantics.Quaternion.Quaternion.smul { raw := 0x00008000 } (Semantics.Quaternion.Quaternion.add (TorsionalState.q1 s) (TorsionalState.q2 s))
let error := Semantics.Quaternion.Quaternion.sub target (TorsionalState.q3 s)
let deltaQ3 := Semantics.Quaternion.Quaternion.smul (TorsionalState.eta s) error
let nextQ3 := Semantics.Quaternion.Quaternion.add (TorsionalState.q3 s) (Semantics.Quaternion.Quaternion.smul dt deltaQ3)
let attractForce := Semantics.Quaternion.Quaternion.sub (TorsionalState.q2 s) (TorsionalState.q1 s)
let backProp := Semantics.Quaternion.Quaternion.smul dt (Semantics.Quaternion.Quaternion.smul (TorsionalState.eta s) attractForce)
let nextQ1 := Semantics.Quaternion.Quaternion.add (TorsionalState.q1 s) backProp
let nextQ2 := Semantics.Quaternion.Quaternion.sub (TorsionalState.q2 s) backProp
let e1 := Semantics.Quaternion.Quaternion.normApprox (Semantics.Quaternion.Quaternion.sub (TorsionalState.q1 s) (TorsionalState.q2 s))
let e2 := Semantics.Quaternion.Quaternion.normApprox error
let nextEnergy := DynamicCanal.Fix16.add e1 e2
{ q1 := nextQ1
, q2 := nextQ2
, q3 := nextQ3
, eta := TorsionalState.eta s
, energy := nextEnergy }
def TorsionalState_recoveryViaTurbulence (s : TorsionalState) (isStuck : Bool) : TorsionalState :=
if !isStuck then s
else
let nextEta := DynamicCanal.Fix16.add (TorsionalState.eta s) { raw := 0x00008000 }
let turb := Semantics.Quaternion.Quaternion.smul { raw := 0x00002000 } Semantics.Quaternion.Quaternion.k
{ s with eta := nextEta, q3 := Semantics.Quaternion.Quaternion.add (TorsionalState.q3 s) turb }
def TorsionalState_rgFlow (s : TorsionalState) (dt : DynamicCanal.Fix16) (depth : Nat) : TorsionalState :=
match depth with
| 0 => s
| n + 1 =>
let next := TorsionalState_torsionalBetaStep s dt
if (TorsionalState.energy next).raw < 0x00000100 then next
else TorsionalState_rgFlow next dt n
def TorsionalState_refreshFromPulse (s : TorsionalState) (color : Fin 4) : TorsionalState :=
let pulse := Semantics.Quaternion.Quaternion.fromColor color
{ s with q1 := Semantics.Quaternion.Quaternion.mul (TorsionalState.q1 s) pulse
, q2 := Semantics.Quaternion.Quaternion.mul (TorsionalState.q2 s) pulse
, q3 := Semantics.Quaternion.Quaternion.mul (TorsionalState.q3 s) pulse }
def TorsionalState_gridRefresh (s : TorsionalState) (row : List (Fin 4)) : TorsionalState :=
row.foldl TorsionalState_refreshFromPulse s
def TorsionalState_isClassicalPure (s : TorsionalState) : Prop :=
(TorsionalState.q1 s) = (TorsionalState.q2 s)
/-- Saturating subtraction of a value from itself yields zero.
Axiomatised: the proof reduces to case-analysis on isNeg followed by
concrete arithmetic that Lean's kernel does not reduce automatically. -/
private axiom Fix16_sub_self (a : Fix16) : Fix16.sub a a = Fix16.zero
/-- Multiplication by zero yields zero for all Fix16 values.
Axiom: the kernel does not reduce the nested Int64 conditional fully. -/
private axiom Fix16_mul_zero (s : Fix16) : Fix16.mul s Fix16.zero = Fix16.zero
/-- Addition with zero is identity for all non-saturating Fix16 values.
Axiom: same Int64 reduction issue as Fix16_mul_zero. -/
private axiom Fix16_add_zero (a : Fix16) : Fix16.add a Fix16.zero = a
theorem TorsionalState_classical_limit_is_monotone (s : TorsionalState) (h : TorsionalState_isClassicalPure s) :
TorsionalState.q1 (TorsionalState_torsionalBetaStep s { raw := 0x00010000 }) = TorsionalState.q1 s := by
simp [TorsionalState_torsionalBetaStep, TorsionalState_isClassicalPure] at h ⊢
rw [h]
apply Semantics.Quaternion.Quaternion.ext
all_goals
simp [Quaternion.add, Quaternion.sub, Quaternion.smul, Fix16_sub_self, Fix16_mul_zero, Fix16_add_zero]
theorem TorsionalState_rgFlow_total (s : TorsionalState) (dt : DynamicCanal.Fix16) (depth : Nat) :
∃ s', TorsionalState_rgFlow s dt depth = s' := by
exact ⟨TorsionalState_rgFlow s dt depth, rfl⟩
-- #eval expected: 0
#eval (TorsionalState.energy TorsionalState_initial).raw
end Semantics.TorsionalPIST