Isabelle Task 4 mostly complete

Add opt_redundancy
Format opt_redundancy test cases
Prove opt_redundancy is sound
Proof for "opt_redundancy never increases area" is incomplete
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Aadi Desai 2022-12-08 14:40:22 +00:00
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@ -141,26 +141,308 @@ next
qed(simp+)
section "Task 4: More logic optimisation"
(* Note: - opt_redundancy is shown to be valid (opt_redundancy_is_sound)
- opt_redundancy never increases area is incomplete (opt_redundancy_never_inc_area)
*)
lemma (* test case *)
"opt_redundancy (AND (INPUT 1) (OR (INPUT 1) (INPUT 2)))
= INPUT 1"
(* by eval *) oops
lemma (* test case *)
"opt_redundancy (AND (AND (INPUT 1) (OR (INPUT 1) (INPUT 2)))
(OR (AND (INPUT 1) (OR (INPUT 1) (INPUT 2))) (INPUT 2)))
= INPUT 1"
(* by eval *) oops
lemma (* test case *)
"opt_redundancy (AND (AND (INPUT 1) (OR (INPUT 1) (INPUT 2)))
(OR (INPUT 2) (AND (INPUT 1) (OR (INPUT 1) (INPUT 2)))))
= INPUT 1"
(* by eval *) oops
lemma (* test case *)
"opt_redundancy (AND (AND (AND (INPUT 1) (OR (INPUT 1) (INPUT 2)))
(OR (INPUT 2) (AND (INPUT 1) (OR (INPUT 1) (INPUT 2)))))
(OR (INPUT 1) (INPUT 2)))
= INPUT 1"
(* by eval *) oops
(* An optimisation that exploits the following Boolean identities:
`a | (a & b) = a`
`(a & b) | a = a`
`a & (a | b) = a`
`(a | b) & a = a`
*)
fun opt_redundancy :: "circuit \<Rightarrow> circuit" where
"opt_redundancy (NOT c) = NOT (opt_redundancy c)"
| "opt_redundancy (OR c1 (AND c2 c3)) = (
let c1' = opt_redundancy c1 in
let c2' = opt_redundancy c2 in
let c3' = opt_redundancy c3 in
if (c1' = c2') | (c1' = c3') then c1'
else if c2' = c3' then OR c1' c2'
else OR c1' (opt_redundancy (AND c2 c3)))"
| "opt_redundancy (OR (AND c1 c2) c3) = (
let c1' = opt_redundancy c1 in
let c2' = opt_redundancy c2 in
let c3' = opt_redundancy c3 in
if (c1' = c3') | (c2' = c3') then c3'
else if c1' = c2' then OR c1' c3'
else OR (opt_redundancy (AND c1 c2)) c3')"
| "opt_redundancy (AND c1 (OR c2 c3)) = (
let c1' = opt_redundancy c1 in
let c2' = opt_redundancy c2 in
let c3' = opt_redundancy c3 in
if (c1' = c2') | (c1' = c3') then c1'
else if c2' = c3' then AND c1' c2'
else AND c1' (opt_redundancy (OR c2 c3)))"
| "opt_redundancy (AND (OR c1 c2) c3) = (
let c1' = opt_redundancy c1 in
let c2' = opt_redundancy c2 in
let c3' = opt_redundancy c3 in
if (c1' = c3') | (c2' = c3') then c3'
else if c1' = c2' then AND c1' c3'
else AND (opt_redundancy (OR c1 c2)) c3')"
| "opt_redundancy (AND c1 c2) = (
let c1' = opt_redundancy c1 in
let c2' = opt_redundancy c2 in
if c1' = c2' then c1' else AND c1' c2')"
| "opt_redundancy (OR c1 c2) = (
let c1' = opt_redundancy c1 in
let c2' = opt_redundancy c2 in
if c1' = c2' then c1' else OR c1' c2')"
| "opt_redundancy TRUE = TRUE"
| "opt_redundancy FALSE = FALSE"
| "opt_redundancy (INPUT i) = INPUT i"
lemma "opt_redundancy (AND (INPUT 1)
(OR (INPUT 1)
(INPUT 2))) = INPUT 1" by eval (* test case *)
lemma "opt_redundancy (AND (AND (INPUT 1)
(OR (INPUT 1)
(INPUT 2)))
(OR (AND (INPUT 1)
(OR (INPUT 1)
(INPUT 2)))
(INPUT 2))) = INPUT 1" by eval (* test case *)
lemma "opt_redundancy (AND (AND (INPUT 1)
(OR (INPUT 1)
(INPUT 2)))
(OR (INPUT 2)
(AND (INPUT 1)
(OR (INPUT 1)
(INPUT 2))))) = INPUT 1" by eval (* test case *)
lemma "opt_redundancy (AND (AND (AND (INPUT 1)
(OR (INPUT 1)
(INPUT 2)))
(OR (INPUT 2)
(AND (INPUT 1)
(OR (INPUT 1)
(INPUT 2)))))
(OR (INPUT 1)
(INPUT 2))) = INPUT 1" by eval (* test case *)
theorem opt_redundancy_is_sound: "opt_redundancy c \<sim> c"
proof (induct rule:opt_redundancy.induct)
case (2 c1 c2 c3)
thus ?case by (smt (verit) opt_redundancy.simps(2) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("3_1" c1 c2 v)
thus ?case by (smt (verit) opt_redundancy.simps(3) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("3_2" c1 c2 v va)
thus ?case by (smt (verit) opt_redundancy.simps(4) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("3_3" c1 c2)
thus ?case by (smt (verit) opt_redundancy.simps(5) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("3_4" c1 c2)
thus ?case by (smt (verit) opt_redundancy.simps(6) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("3_5" c1 c2 v)
thus ?case by (smt (verit) opt_redundancy.simps(7) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case (4 c1 c2 c3)
thus ?case by (smt (verit) opt_redundancy.simps(8) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("5_1" c1 c2 v)
thus ?case by (smt (verit) opt_redundancy.simps(9) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("5_2" c1 c2 v va)
thus ?case by (smt (verit) opt_redundancy.simps(10) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("5_3" c1 c2)
thus ?case by (smt (verit) opt_redundancy.simps(11) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("5_4" c1 c2)
thus ?case by (smt (verit) opt_redundancy.simps(12) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("5_5" c1 c2 v)
thus ?case by (smt (verit) opt_redundancy.simps(13) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_1" va v)
thus ?case by (smt (verit) opt_redundancy.simps(14) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_2" va vb v)
thus ?case by (smt (verit) opt_redundancy.simps(15) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_6" vb v va)
thus ?case by (smt (verit) opt_redundancy.simps(19) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_7" vb vc v va)
thus ?case by (smt (verit) opt_redundancy.simps(20) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_8" v va)
thus ?case by (smt (verit) opt_redundancy.simps(21) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_9" v va)
thus ?case by (smt (verit) opt_redundancy.simps(22) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_10" vb v va)
thus ?case by (smt (verit) opt_redundancy.simps(23) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_12" v va)
thus ?case by (smt (verit) opt_redundancy.simps(25) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_17" v va)
thus ?case by (smt (verit) opt_redundancy.simps(30) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_22" va vb v)
thus ?case by (smt (verit) opt_redundancy.simps(35) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("6_25" va v)
thus ?case by (smt (verit) opt_redundancy.simps(38) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_1" va v)
thus ?case by (smt (verit) opt_redundancy.simps(39) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_2" va vb v)
thus ?case by (smt (verit) opt_redundancy.simps(40) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_6" vb v va)
thus ?case by (smt (verit) opt_redundancy.simps(44) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_7" vb vc v va)
thus ?case by (smt (verit) opt_redundancy.simps(45) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_8" v va)
thus ?case by (smt (verit) opt_redundancy.simps(46) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_9" v va)
thus ?case by (smt (verit) opt_redundancy.simps(47) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_10" vb v va)
thus ?case by (smt (verit) opt_redundancy.simps(48) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_12" v va)
thus ?case by (smt (verit) opt_redundancy.simps(50) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_17" v va)
thus ?case by (smt (verit) opt_redundancy.simps(55) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_22" va vb v)
thus ?case by (smt (verit) opt_redundancy.simps(60) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
next
case ("7_25" va v)
thus ?case by (smt (verit) opt_redundancy.simps(63) circuits_equiv.elims(1) simulate.simps(1) simulate.simps(2))
qed(simp+)
theorem opt_redundancy_never_inc_area: "area (opt_redundancy c) \<le> area c"
proof (induct rule:opt_redundancy.induct)
case (2 c1 c2 c3)
(* area (opt_redundancy (OR c1 (AND c2 c3))) \<le> area (OR c1 (AND c2 c3)) *)
let ?c1' = "opt_redundancy c1"
let ?c2' = "opt_redundancy c2"
let ?c3' = "opt_redundancy c3"
from 2 have IH:"area (OR ?c1' (AND ?c2' ?c3')) \<le> area (OR c1 (AND c2 c3))" by fastforce
have a:"(area (opt_redundancy (OR c1 (AND c2 c3))) = area ?c1')
\<or> (area (opt_redundancy (OR c1 (AND c2 c3))) = area (OR ?c1' ?c2'))
\<or> (area (opt_redundancy (OR c1 (AND c2 c3))) = area (OR ?c1' (opt_redundancy (AND c2 c3))))"
by (smt opt_redundancy.simps(2))
have b:"area ?c1' \<le> area (OR c1 (AND c2 c3))" using IH by simp
have c:"area (OR ?c1' ?c2') \<le> area (OR c1 (AND c2 c3))" using IH by simp
have d:"area (OR ?c1' (opt_redundancy (AND c2 c3))) \<le> area (OR c1 (AND c2 c3))" using IH sorry
thus ?case using a b c d by metis
next
case ("3_1" c1 c2 v)
thus ?case sorry
next
case ("3_2" c1 c2 v va)
thus ?case sorry
next
case ("3_3" c1 c2)
thus ?case sorry
next
case ("3_4" c1 c2)
thus ?case sorry
next
case ("3_5" c1 c2 v)
thus ?case sorry
next
case (4 c1 c2 c3)
thus ?case sorry
next
case ("5_1" c1 c2 v)
thus ?case sorry
next
case ("5_2" c1 c2 v va)
thus ?case sorry
next
case ("5_3" c1 c2)
thus ?case sorry
next
case ("5_4" c1 c2)
thus ?case sorry
next
case ("5_5" c1 c2 v)
thus ?case sorry
next
case ("6_1" va v)
thus ?case sorry
next
case ("6_2" va vb v)
thus ?case sorry
next
case ("6_6" vb v va)
thus ?case sorry
next
case ("6_7" vb vc v va)
thus ?case sorry
next
case ("6_8" v va)
thus ?case sorry
next
case ("6_9" v va)
thus ?case sorry
next
case ("6_10" vb v va)
thus ?case sorry
next
case ("6_12" v va)
thus ?case sorry
next
case ("6_17" v va)
thus ?case sorry
next
case ("6_22" va vb v)
thus ?case sorry
next
case ("6_25" va v)
thus ?case sorry
next
case ("7_1" va v)
thus ?case sorry
next
case ("7_2" va vb v)
thus ?case sorry
next
case ("7_6" vb v va)
thus ?case sorry
next
case ("7_7" vb vc v va)
thus ?case sorry
next
case ("7_8" v va)
thus ?case sorry
next
case ("7_9" v va)
thus ?case sorry
next
case ("7_10" vb v va)
thus ?case sorry
next
case ("7_12" v va)
thus ?case sorry
next
case ("7_17" v va)
thus ?case sorry
next
case ("7_22" va vb v)
thus ?case sorry
next
case ("7_25" va v)
thus ?case sorry
qed(simp+)
end