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import OAI.LinearAlgebra.MatrixMultiplication.CoppersmithWinograd.ComplexCW75Primitive
import OAI.LinearAlgebra.MatrixMultiplication.Polynomial.ComplexPolynomialKernelExecution
namespace OAI
/-! Coppersmith–Winograd tensors, tensor powers and local restrictions. -/
noncomputable section
namespace MatrixMultiplication.Foundation.CW75InitialExecution
open Polynomial
open scoped BigOperators Classical
abbrev Word := CW75Primitive.Word
abbrev Blocks (N : ℕ) := Fin N → Word
def fullSource (N : ℕ) : Tensor ℂ (Blocks N) (Blocks N) (Blocks N) :=
Tensor.power (Tensor.power CoppersmithWinograd.tensor 3) N
def support {N : ℕ} (x y z : Blocks N) : Prop := fullSource N x y z ≠ 0
theorem support_iff {N : ℕ} (x y z : Blocks N) :
support x y z ↔ ∀ i j, (x i j).val + (y i j).val + (z i j).val = 2 := by
simp [support, fullSource, Tensor.power, Finset.prod_ne_zero_iff,
CWOriginalWords.tensor_ne_zero_iff]
def boundaryPolynomial (x y z : Word) : Polynomial ℂ :=
∏ i, CWBoundary.scalingPolynomial (x i) (y i) (z i)
def boundaryNormalized (x y z : Word) : Polynomial ℂ :=
∏ i, (C (CWBoundary.tensor (x i) (y i) (z i)) +
X ^ 2 * C (CWBoundary.deleted (x i) (y i) (z i)))
theorem boundaryPolynomial_factor (x y z : Word) :
boundaryPolynomial x y z = X ^ 3 * boundaryNormalized x y z := by
have hp (i : Fin 3) : CWBoundary.scalingPolynomial (x i) (y i) (z i) =
X * (C (CWBoundary.tensor (x i) (y i) (z i)) +
X ^ 2 * C (CWBoundary.deleted (x i) (y i) (z i))) := by
rw [CWBoundary.scalingPolynomial_apply]
ring
simp [boundaryPolynomial, boundaryNormalized, hp, Finset.prod_mul_distrib]
theorem boundaryPolynomial_vanishes (x y z : Word) (j : ℕ) (hj : j < 3) :
(boundaryPolynomial x y z).coeff j = 0 := by
rw [boundaryPolynomial_factor]
simp only [Polynomial.coeff_X_pow_mul', Nat.not_le_of_lt hj, ite_false]
theorem boundaryPolynomial_leading (x y z : Word) :
(boundaryPolynomial x y z).coeff 3 = CW75Primitive.source x y z := by
rw [boundaryPolynomial_factor]
simp [Polynomial.coeff_X_pow_mul', boundaryNormalized,
Polynomial.coeff_zero_prod, CW75Primitive.source, Tensor.power]
def completionPolynomial (x y z : Word) : Polynomial ℂ :=
(if CW75Primitive.hasB x then X else 1) *
(if CW75Primitive.hasC y then X else 1) *
(if CW75Primitive.allA z then 0 else 1)
private theorem boundary_one (x y z : Fin 3) (h : CWBoundary.tensor x y z ≠ 0) :
CWBoundary.tensor x y z = 1 := by
by_cases hd : x = 1 ∧ y = 0 ∧ z = 1
· simp [CWBoundary.tensor, hd] at h
· by_cases hs : x.val + y.val + z.val = 2
· simp [CWBoundary.tensor, CoppersmithWinograd.tensor, hd, hs]
· simp [CWBoundary.tensor, CoppersmithWinograd.tensor, hd, hs] at h
private theorem boundarySource_one (x y z : Word) (h : CW75Primitive.source x y z ≠ 0) :
CW75Primitive.source x y z = 1 := by
unfold CW75Primitive.source Tensor.power
apply Finset.prod_eq_one
intro i hi
exact boundary_one _ _ _ (CW75Primitive.source_factors x y z h i)
theorem retained_coefficient_one (x y z : Word) (h : CW75Primitive.tensor x y z ≠ 0) :
CW75Primitive.tensor x y z = 1 := by
by_cases hr : CW75Primitive.retained x y z
· rw [CW75Primitive.tensor, ite_eq_left hr] at h ⊢
exact boundarySource_one x y z h
· simp [CW75Primitive.tensor, hr] at h
private theorem completion_eq (x y z : Word) (h : CW75Primitive.source x y z ≠ 0) :
completionPolynomial x y z = CW75Primitive.polynomial x y z := by
have hone := boundarySource_one x y z h
rw [CW75Primitive.polynomial_apply]
by_cases hz : CW75Primitive.allA z <;> simp [completionPolynomial, hone, hz]
private theorem source_mul_retained (x y z : Word) :
CW75Primitive.source x y z * CW75Primitive.tensor x y z =
CW75Primitive.tensor x y z := by
by_cases hs : CW75Primitive.source x y z = 0
· simp [CW75Primitive.tensor, hs]
· rw [boundarySource_one x y z hs, one_mul]
def leftBlock (x : Word) : Polynomial ℂ :=
Polynomial.expand ℂ 2 (∏ i, CWBoundary.outerWeight X (x i)) *
(if CW75Primitive.hasB x then X else 1)
def middleBlock (y : Word) : Polynomial ℂ :=
Polynomial.expand ℂ 2 (∏ i, CWBoundary.middleWeight X (y i)) *
(if CW75Primitive.hasC y then X else 1)
def rightBlock (z : Word) : Polynomial ℂ :=
Polynomial.expand ℂ 2 (∏ i, CWBoundary.outerWeight X (z i)) *
(if CW75Primitive.allA z then 0 else 1)
def blockKernel (x y z : Word) : Polynomial ℂ := leftBlock x * middleBlock y * rightBlock z
theorem blockKernel_factor (x y z : Word)
(hs : ∀ i, (x i).val + (y i).val + (z i).val = 2) :
blockKernel x y z = Polynomial.expand ℂ 2 (boundaryPolynomial x y z) *
completionPolynomial x y z := by
have hpoint (i : Fin 3) :
CWBoundary.outerWeight X (x i) * CWBoundary.middleWeight X (y i) *
CWBoundary.outerWeight X (z i) = CWBoundary.scalingPolynomial (x i) (y i) (z i) := by
unfold CWBoundary.scalingPolynomial
rw [CWBoundary.outerMap, CWBoundary.middleMap, CWBoundary.restrict_diagonal_apply]
simp [CoppersmithWinograd.tensor, hs i]
have hprod : (∏ i, CWBoundary.outerWeight X (x i)) *
(∏ i, CWBoundary.middleWeight X (y i)) * (∏ i, CWBoundary.outerWeight X (z i)) =
boundaryPolynomial x y z := by
simp only [boundaryPolynomial, ← hpoint, Finset.prod_mul_distrib]
calc
blockKernel x y z = Polynomial.expand ℂ 2
((∏ i, CWBoundary.outerWeight X (x i)) *
(∏ i, CWBoundary.middleWeight X (y i)) * (∏ i, CWBoundary.outerWeight X (z i))) *
completionPolynomial x y z := by
simp only [blockKernel, leftBlock, middleBlock, rightBlock, completionPolynomial, map_mul]
ring
_ = _ := by rw [hprod]
theorem blockKernel_vanishes (x y z : Word)
(hs : ∀ i, (x i).val + (y i).val + (z i).val = 2)
(j : ℕ) (hj : j < 7) : (blockKernel x y z).coeff j = 0 := by
rw [blockKernel_factor x y z hs]
apply PolynomialControlledKernel.expanded_mul_vanishes_of_leading_support
(boundaryPolynomial x y z) (completionPolynomial x y z) 3 1
(CW75Primitive.source x y z)
(boundaryPolynomial_vanishes x y z) (boundaryPolynomial_leading x y z) _ j hj
intro hn k hk
rw [completion_eq x y z hn]
have hkzero : k = 0 := by omega
subst k
simp [CW75Primitive.polynomial_coeff]
theorem blockKernel_leading (x y z : Word)
(hs : ∀ i, (x i).val + (y i).val + (z i).val = 2) :
(blockKernel x y z).coeff 7 = CW75Primitive.tensor x y z := by
rw [blockKernel_factor x y z hs]
have h := PolynomialControlledKernel.expanded_mul_leading_of_leading_support
(boundaryPolynomial x y z) (completionPolynomial x y z) 3 1
(CW75Primitive.source x y z) (CW75Primitive.tensor x y z)
(boundaryPolynomial_vanishes x y z) (boundaryPolynomial_leading x y z) (by
intro hn
rw [completion_eq x y z hn]
simp [CW75Primitive.polynomial_coeff])
exact h.trans (source_mul_retained x y z)
private theorem degree_product {n D : ℕ} (f : Fin n → Polynomial ℂ)
(h : ∀ i, (f i).degree ≤ D) : (∏ i, f i).degree ≤ D * n := by
apply Polynomial.degree_le_of_natDegree_le
calc
(∏ i, f i).natDegree ≤ ∑ i, (f i).natDegree := Polynomial.natDegree_prod_le _ _
_ ≤ ∑ _i : Fin n, D := by
apply Finset.sum_le_sum
intro i hi
exact Polynomial.natDegree_le_of_degree_le (h i)
_ = D * n := by simp [Nat.mul_comm]
private theorem degree_expanded_product (P Q : Polynomial ℂ) {d e : ℕ}
(hP : P.degree ≤ d) (hQ : Q.degree ≤ e) :
(Polynomial.expand ℂ 2 P * Q).degree ≤ d * 2 + e := by
apply Polynomial.degree_le_of_natDegree_le
apply Polynomial.natDegree_mul_le_of_le
· rw [Polynomial.natDegree_expand]
exact Nat.mul_le_mul_right 2 (Polynomial.natDegree_le_of_degree_le hP)
· exact Polynomial.natDegree_le_of_degree_le hQ
private theorem outerWeight_degree (a : Fin 3) :
(CWBoundary.outerWeight (X : Polynomial ℂ) a).degree ≤ 1 := by
by_cases h : a = 1 <;> simp [CWBoundary.outerWeight, h]
private theorem middleWeight_degree (a : Fin 3) :
(CWBoundary.middleWeight (X : Polynomial ℂ) a).degree ≤ 1 := by
by_cases h : a = 1 <;> simp [CWBoundary.middleWeight, h]
theorem leftBlock_degree (x : Word) : (leftBlock x).degree ≤ 7 := by
apply degree_expanded_product (d := 3) (e := 1)
(∏ i, CWBoundary.outerWeight X (x i)) (if CW75Primitive.hasB x then X else 1)
(degree_product _ (fun i => outerWeight_degree (x i)))
by_cases h : CW75Primitive.hasB x <;> simp [h]
theorem middleBlock_degree (y : Word) : (middleBlock y).degree ≤ 7 := by
apply degree_expanded_product (d := 3) (e := 1)
(∏ i, CWBoundary.middleWeight X (y i)) (if CW75Primitive.hasC y then X else 1)
(degree_product _ (fun i => middleWeight_degree (y i)))
by_cases h : CW75Primitive.hasC y <;> simp [h]
theorem rightBlock_degree (z : Word) : (rightBlock z).degree ≤ 6 := by
apply degree_expanded_product (d := 3) (e := 0)
(∏ i, CWBoundary.outerWeight X (z i)) (if CW75Primitive.allA z then 0 else 1)
(degree_product _ (fun i => outerWeight_degree (z i)))
by_cases h : CW75Primitive.allA z <;> simp [h]
def auxiliary : Tensor ℂ PUnit.{1} PUnit.{1} PUnit.{1} := fun _ _ _ => 1
theorem auxiliary_rank : Tensor.RankAtMost auxiliary 1 := by
refine ⟨fun _ _ => 1, fun _ _ => 1, fun _ _ => 1, ?_⟩
funext x y z
simp [auxiliary, Tensor.rankOne]
def leftMap {N : ℕ} (x : Blocks N) (_ : PUnit.{1} × PUnit.{1}) (_ : PUnit.{1}) : Polynomial ℂ :=
∏ i, leftBlock (x i)
def middleMap {N : ℕ} (y : Blocks N) (_ : PUnit.{1} × PUnit.{1}) (_ : PUnit.{1}) : Polynomial ℂ :=
∏ i, middleBlock (y i)
def rightMap {N : ℕ} (z : Blocks N) (_ : PUnit.{1} × PUnit.{1}) (_ : PUnit.{1}) : Polynomial ℂ :=
∏ i, rightBlock (z i)
def value {N : ℕ} : Tensor ℂ (Blocks N × (PUnit.{1} × PUnit.{1}))
(Blocks N × (PUnit.{1} × PUnit.{1})) (Blocks N × (PUnit.{1} × PUnit.{1})) :=
fun x y z => ∏ i, CW75Primitive.tensor (x.1 i) (y.1 i) (z.1 i)
theorem kernel_eq {N : ℕ} (x y z : Blocks N × (PUnit.{1} × PUnit.{1})) :
PolynomialLocalConstruction.kernel auxiliary leftMap middleMap rightMap x y z =
∏ i, blockKernel (x.1 i) (y.1 i) (z.1 i) := by
simp [PolynomialLocalConstruction.kernel, LocalMaps.fiberTransform,
auxiliary, leftMap, middleMap, rightMap, blockKernel, Finset.prod_mul_distrib]
theorem kernel_coefficients {N : ℕ} (x y z : Blocks N × (PUnit.{1} × PUnit.{1}))
(hs : support x.1 y.1 z.1) :
(∀ j, j < 7 * N →
(PolynomialLocalConstruction.kernel auxiliary leftMap middleMap rightMap x y z).coeff j = 0) ∧
(PolynomialLocalConstruction.kernel auxiliary leftMap middleMap rightMap x y z).coeff (7 * N) =
value x y z := by
have hsites := (support_iff x.1 y.1 z.1).mp hs
have hd (i : Fin N) : X ^ 7 ∣ blockKernel (x.1 i) (y.1 i) (z.1 i) :=
Polynomial.X_pow_dvd_iff.mpr (blockKernel_vanishes _ _ _ (hsites i))
let Q : Fin N → Polynomial ℂ := fun i => Classical.choose (hd i)
have hQ (i : Fin N) : blockKernel (x.1 i) (y.1 i) (z.1 i) = X ^ 7 * Q i :=
Classical.choose_spec (hd i)
have hQzero (i : Fin N) : (Q i).coeff 0 = CW75Primitive.tensor (x.1 i) (y.1 i) (z.1 i) := by
have h := blockKernel_leading _ _ _ (hsites i)
rw [hQ] at h
simpa only [Polynomial.coeff_X_pow_mul', le_refl, ite_true, Nat.sub_self] using h
have hfactor : (∏ i, blockKernel (x.1 i) (y.1 i) (z.1 i)) =
X ^ (7 * N) * ∏ i, Q i := by
simp only [hQ, Finset.prod_mul_distrib, Finset.prod_const,
Finset.card_univ, Fintype.card_fin, ← pow_mul]
simp only [kernel_eq, hfactor]
constructor
· intro j hj
simp only [Polynomial.coeff_X_pow_mul', Nat.not_le_of_lt hj, ite_false]
· simp only [Polynomial.coeff_X_pow_mul', le_refl, ite_true, Nat.sub_self,
Polynomial.coeff_zero_prod, hQzero, value]
def execution (N : ℕ) : PolynomialKernelExecution.Execution
(Blocks N) (Blocks N) (Blocks N) PUnit.{1} PUnit.{1} PUnit.{1} PUnit.{1} PUnit.{1} PUnit.{1} PUnit.{1} support where
auxiliary := auxiliary
rankBound := 1
auxiliary_rank := auxiliary_rank
order := 7 * N
leftDegree := 7 * N
middleDegree := 7 * N
rightDegree := 6 * N
leftMap := leftMap
middleMap := middleMap
rightMap := rightMap
left_degree := fun x _ _ => degree_product _ (fun i => leftBlock_degree (x i))
middle_degree := fun y _ _ => degree_product _ (fun i => middleBlock_degree (y i))
right_degree := fun z _ _ => degree_product _ (fun i => rightBlock_degree (z i))
value := value
vanishes := fun x y z hs => (kernel_coefficients x y z hs).1
leading := fun x y z hs => (kernel_coefficients x y z hs).2
synchronized := fun _ _ _ _ _ => ⟨Subsingleton.elim _ _, Subsingleton.elim _ _⟩
@[simp] theorem execution_value (N : ℕ) : (execution N).value = value := rfl
theorem value_ne_zero_iff {N : ℕ} (x y z : Blocks N × (PUnit.{1} × PUnit.{1})) :
(execution N).value x y z ≠ 0 ↔
∀ i, CW75Primitive.tensor (x.1 i) (y.1 i) (z.1 i) ≠ 0 := by
simp [execution_value, value, Finset.prod_ne_zero_iff]
theorem value_retained {N : ℕ} (x y z : Blocks N × (PUnit.{1} × PUnit.{1})) :
(execution N).value x y z =
if ∀ i, CW75Primitive.tensor (x.1 i) (y.1 i) (z.1 i) ≠ 0 then 1 else 0 := by
by_cases h : ∀ i, CW75Primitive.tensor (x.1 i) (y.1 i) (z.1 i) ≠ 0
· simp only [ite_eq_left h, execution_value, value]
apply Finset.prod_eq_one
intro i hi
exact retained_coefficient_one _ _ _ (h i)
· rw [ite_eq_right h]
by_contra hn
exact h ((value_ne_zero_iff x y z).mp hn)
end MatrixMultiplication.Foundation.CW75InitialExecution
end
end OAI