roseking's picture
Sync from openai/math@faee2cf485a8 (part 11)
6fe30b6 verified
Raw History Blame Contribute Delete
5.56 kB
import OAI.Computability.FourierTransform.LayoutPrograms
namespace OAI
namespace PowerSaving.RAM
open Ty Finset
noncomputable section
universe U
variable {ι : Type U} {m : Bool}
namespace Small
variable {B P Q : ι → ℕ}
theorem sub (h : Small B P) : Small B (fun i => P i-Q i) :=
h.mono fun _ => Nat.sub_le _ _
theorem div (h : Small B P) : Small B (fun i => P i/Q i) :=
h.mono fun _ => Nat.div_le_self _ _
theorem mod (h : Small B P) : Small B (fun i => P i%Q i) :=
h.mono fun _ => Nat.mod_le _ _
end Small
namespace Can
variable {s t : Ty} {x : ι → T s} {B W A Q : ι → ℕ}
lemma minus (h : Can m B s w x A W) (k : Can m B s w x Q W)
(hh : Small B A) : Can m B s w x (fun i => A i - Q i) W :=
h.wsub k hh.sub
lemma times (h : Can m B s w x A W) (k : Can m B s w x Q W)
(hh : Small B A) (gg : Small B Q) : Can m B s w x (fun i => A i * Q i) W :=
h.wmul k (hh.mul gg)
lemma plus (h : Can m B s w x A W) (k : Can m B s w x Q W)
(hh : Small B A) (gg : Small B Q) : Can m B s w x (fun i => A i + Q i) W :=
h.wadd k (hh.add gg)
lemma dvdW (h : Can m B s w x A W) (k : Can m B s w x Q W) (hh : Small B A) :
Can m B s w x (fun i => A i / Q i) W :=
h.wdiv k hh.div
lemma modW (h : Can m B s w x A W) (k : Can m B s w x Q W) (hh : Small B A) :
Can m B s w x (fun i => A i % Q i) W :=
h.wmod k hh.mod
lemma wpow_fixed (n : ℕ) (h : Can m B s w x A W) (hh : Small B A) :
Can m B s w x (fun i => (A i)^n) W := by
induction n with
| zero => simpa using wc (s:=s) (m:=m) (B:=B) (x:=x) (W:=W) 1
| succ n ih => simpa [pow_succ] using ih.times h (hh.pow n) hh
/-- Cost-sensitive powering of two to a variable exponent by doubling. -/
lemma wTwo (h : Can m B s w x A W) (hh : Small B A)
(hq : Small B fun i => 2^A i) (ha : Dom W A) :
Can m B s w x (fun i => 2^A i) W := by
let v (_ : ι) (n : ℕ) := 2^n
have hs : Can m (fun d : During A => B d.i) (p s (p w w)) w
(fun d => (x d.i, d.j, v d.i d.j)) (fun d => v d.i (d.j+1)) (fun _ => 0) := by
have hp : Small (fun d : During A => B d.i) fun d => v d.i d.j :=
(hq.reindex During.i).mono (fun d => Nat.pow_le_pow_right (by omega) d.hj.le)
unfold v at *
simp only [pow_succ]
exact (Can.snd Can.second).times (Can.wc _) hp (Small.const ..)
have ht := Can.loop (t:=w) (v:=v) (W':=fun _ => 0) (uB:=fun _ _ => 0) h
(by simpa only [v,pow_zero] using (Can.wc (m:=m) (W:=fun _ => 0)
(B:=B) (s:=s) (x:=x) 1)) hs hh
simp only [Finset.sum_const_zero,Nat.add_zero] at ht
exact ht.weaken ((Dom.self W).add ha)
end Can
namespace Can
variable {s t : Ty} {x : ι → T s} {B W A Q : ι → ℕ}
lemma neg {cl} {z : ι→ℂ} (h : Can m B s (c cl) x z W) :
Can m B s (c cl) x (fun i => -(z i)) W := by
simpa using (Can.sub Can.zero h)
lemma cNat (n : ℕ) : Can m B s sc x (fun _ => (n:ℂ)) W := by
induction n with
| zero =>
simp only [Nat.cast_zero]
exact Can.zero
| succ n ih => simpa using ih.add Can.one
lemma cInt (n : ℤ) : Can m B s sc x (fun _ => (n:ℂ)) W := by
cases n with
| ofNat n =>
simpa using (cNat (s:=s) (m:=m) (B:=B) (W:=W) (x:=x) n)
| negSucc n =>
simpa using (cNat (s:=s) (m:=m) (B:=B) (W:=W) (x:=x) (n+1)).neg
lemma rat (z : ℚ) : Can m B s sc x (fun _ => (z:ℂ)) W := by
rw [Rat.cast_def]
simp only [div_eq_mul_inv]
exact (Can.cInt _).mul ((Can.cNat _).inv (by intro i; exact_mod_cast z.den_nz))
lemma cpow_fixed (n : ℕ) {v : ι→ℂ} (h : Can m B s sc x v W) :
Can m B s sc x (fun i => v i ^ n) W := by
induction n with
| zero =>
simp only [pow_zero]
exact Can.one
| succ n ih => simpa [pow_succ] using ih.mul h
lemma prod_cconst {μ : Type*} [Fintype μ] {v : μ→ι→ℂ}
(h : ∀ i : μ, Can m B s sc x (v i) W) :
Can m B s sc x (fun j => ∏ i, v i j) W := by
classical
have hh (l : Finset μ) : Can m B s sc x (fun j => ∏ i∈l,v i j) W := by
induction l using Finset.induction with
| empty =>
simp only [prod_empty]
exact Can.one
| insert i l hi ih =>
simp only [prod_insert hi]
exact (h i).mul ih
exact hh _
end Can
namespace Can
-- product addressing at arbitrary parameter types
variable {s t : Ty} {x : ι → T s} {B W : ι → ℕ}
variable {α β : ι → Type*} {L : ∀ i, Layout (α i)} {R : ∀ i, Layout (β i)}
{u : ∀ i, α i × β i}
lemma addr_join (h : Can m B s w x (fun i => (L i).loc (u i).1) W)
(k : Can m B s w x (fun i => (R i).loc (u i).2) W)
(d : Can m B s w x (fun i => (R i).n) W)
(hl : Small B fun i => (L i).n) (hr : Small B fun i => (R i).n) :
Can m B s w x (fun i => ((L i).pair (R i)).loc (u i)) W :=
(h.times d (Small.loc (x:=fun i => (u i).1) (L:=L) hl) hr).plus k
((Small.loc (x:=fun i => (u i).1) (L:=L) hl).mul hr)
(Small.loc (x:=fun i => (u i).2) (L:=R) hr)
lemma addr_high (h : Can m B s w x (fun i => ((L i).pair (R i)).loc (u i)) W)
(k : Can m B s w x (fun i => (R i).n) W)
(hs : Small B fun i => (L i).n*(R i).n) :
Can m B s w x (fun i => (L i).loc (u i).1) W :=
(h.dvdW k (Small.loc (L:=fun i => (L i).pair (R i)) (x:=u) hs)).cong
(fun _ => rfl) (fun _ => Layout.pair_div ..)
lemma addr_low (h : Can m B s w x (fun i => ((L i).pair (R i)).loc (u i)) W)
(k : Can m B s w x (fun i => (R i).n) W)
(hs : Small B fun i => (L i).n*(R i).n) :
Can m B s w x (fun i => (R i).loc (u i).2) W :=
(h.modW k (Small.loc (L:=fun i => (L i).pair (R i)) (x:=u) hs)).cong
(fun _ => rfl) (fun _ => Layout.pair_mod ..)
end Can
end
end PowerSaving.RAM
end OAI