test: add cdcl, encoder, and difference logic tests

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dualfroz committed 2026-08-28 15:50:00 +02:00
1 parent ccaa52b887
commit cca8377dfb
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@@ -89,6 +89,79 @@ tests =
, check "formula parser evaluates a & (b | ~c) correctly" parserEvaluates
, check "formula parser respects precedence (~ then & then ->)" parserPrecedence
, check "Luby sequence prefix matches reference" lubyPrefixOk
, check "Luby is always a power of two" (all isPowerOfTwo (lubySequence 200))
, check ("CDCL agrees with brute force on " ++ show (length randomCnfs) ++ " random CNFs")
(all cdclCorrect randomCnfs)
, check ("CDCL agrees with DPLL on " ++ show (length randomCnfs) ++ " random CNFs")
(all cdclMatchesDpll randomCnfs)
, check ("CDCL finds a verified model for " ++ show (length satisfiableCnfs)
++ " constructed-satisfiable CNFs")
(all cdclModelVerifies satisfiableCnfs)
, check "CDCL: empty clause is UNSAT" (solveCdcl (CNF [[]]) == CdclUnsat)
, check "CDCL: empty CNF is SAT" (isCdclSat (solveCdcl (CNF [])))
, check "CDCL: (a v b) ^ (~a) forces a=False, b=True" cdclForcedSmall
, check ("CDCL solves Tseitin CNFs equisat to brute force on "
++ show (length randomFormulas) ++ " formulas")
(all cdclTseitinEquisat randomFormulas)
, check "CDCL: PHP(3,2) is UNSAT" (solveCdcl (pigeonhole 3 2) == CdclUnsat)
, check "CDCL: PHP(4,3) is UNSAT" (solveCdcl (pigeonhole 4 3) == CdclUnsat)
, check "CDCL: PHP(5,4) is UNSAT" (solveCdcl (pigeonhole 5 4) == CdclUnsat)
, check "CDCL: PHP(6,5) is UNSAT" (solveCdcl (pigeonhole 6 5) == CdclUnsat)
, check "CDCL: PHP(7,6) is UNSAT" (solveCdcl (pigeonhole 7 6) == CdclUnsat)
, check "CDCL: PHP(5,5) is SAT with a verified model" (cdclModelVerifies (pigeonhole 5 5))
, check "at-most-one encodes cardinality <= 1 exactly" (all atMostOneCorrect [1 .. 5])
, check "exactly-one encodes cardinality == 1 exactly" (all exactlyOneCorrect [1 .. 5])
, check "at-least-one is a single clause of all literals" atLeastOneShape
, check "queens N=1 is SAT" (isCdclSat (solveCdcl (queens 1)))
, check "queens N=2 is UNSAT" (solveCdcl (queens 2) == CdclUnsat)
, check "queens N=3 is UNSAT" (solveCdcl (queens 3) == CdclUnsat)
, check "queens N=4..10 are SAT with valid placements"
(all queensSatValid [4 .. 10])
, check "coloring: K4 needs 4 colors (3 is UNSAT)"
(solveCdcl (coloring 3 completeK4) == CdclUnsat)
, check "coloring: K4 is 4-colorable with a valid coloring"
(coloringSatValid 4 completeK4)
, check "coloring: odd cycle C5 is not 2-colorable"
(solveCdcl (coloring 2 cycleC5) == CdclUnsat)
, check "coloring: odd cycle C5 is 3-colorable with a valid coloring"
(coloringSatValid 3 cycleC5)
, check "coloring: even cycle C6 is 2-colorable with a valid coloring"
(coloringSatValid 2 cycleC6)
, check "coloring: bipartite graph is 2-colorable with a valid coloring"
(coloringSatValid 2 bipartite)
, check "sudoku: a real puzzle is solved with a valid grid"
(sudokuSolvesValid sudokuPuzzle)
, check "sudoku: two identical givens in a row make it UNSAT"
(solveCdcl (sudoku 3 [(1, 1, 5), (1, 2, 5)]) == CdclUnsat)
, check "preprocess: subsumption preserves the model set on random CNFs"
(all (\c -> modelSetEq c (subsume c)) randomCnfs)
, check "preprocess: self-subsuming resolution preserves the model set"
(all (\c -> modelSetEq c (selfSubsume c)) randomCnfs)
, check "preprocess: unit propagation is equisatisfiable and sound"
(all unitPropSound randomCnfs)
, check "preprocess: pure literal elimination is equisatisfiable"
(all pureElimEquisat randomCnfs)
, check ("preprocess: full pipeline is correct on " ++ show (length randomCnfs)
++ " random CNFs")
(all preprocessCorrect randomCnfs)
, check "difference logic: a negative cycle is UNSAT" (solveDl dlNegCycle == DlUnsat)
, check "difference logic: a feasible system is SAT with a verified model"
(dlSatVerified dlFeasible)
, check "difference logic: disjunctive constraint picks a feasible branch"
(dlSatVerified dlDisjunctive)
, check ("difference logic agrees with bounded brute force on "
++ show (length randomDlProblems) ++ " random problems")
(all dlAgrees randomDlProblems)
]
check :: String -> Bool -> IO Bool
@@ -302,3 +375,198 @@ randLeaf s0 = let (k, s1) = randInt 0 (length atomPool - 1) s0
randomFormulas :: [Formula]
randomFormulas = fst (genN 200 (randFormula 3) 4242)
isCdclSat :: CdclResult -> Bool
isCdclSat (CdclSat _) = True
isCdclSat CdclUnsat = False
lubyPrefixOk :: Bool
lubyPrefixOk =
lubySequence 15 == [1, 1, 2, 1, 1, 2, 4, 1, 1, 2, 1, 1, 2, 4, 8]
isPowerOfTwo :: Int -> Bool
isPowerOfTwo n = n > 0 && (n .&. (n - 1)) == 0
cdclCorrect :: CNF -> Bool
cdclCorrect cnf = case solveCdcl cnf of
CdclSat model -> satisfies model cnf && bruteForceSat cnf
CdclUnsat -> not (bruteForceSat cnf)
cdclMatchesDpll :: CNF -> Bool
cdclMatchesDpll cnf = isCdclSat (solveCdcl cnf) == isSat (solve cnf)
cdclModelVerifies :: CNF -> Bool
cdclModelVerifies cnf = case solveCdcl cnf of
CdclSat model -> satisfies model cnf
CdclUnsat -> False
cdclForcedSmall :: Bool
cdclForcedSmall = case solveCdcl cnfSatSmall of
CdclSat model -> Map.lookup (Var 1) model == Just False
&& Map.lookup (Var 2) model == Just True
CdclUnsat -> False
cdclTseitinEquisat :: Formula -> Bool
cdclTseitinEquisat f = isCdclSat (solveCdcl (tsCnf (tseitin f))) == formulaSat f
countTrue :: Int -> Assignment -> Int
countTrue n asn = length [ () | i <- [1 .. n], Map.findWithDefault False (Var i) asn ]
atMostOneCorrect :: Int -> Bool
atMostOneCorrect n =
all (\asn -> satisfies asn cnf == (countTrue n asn <= 1)) (allAssignments vs)
where
lits = [ posLit (Var i) | i <- [1 .. n] ]
cnf = CNF (atMostOne lits)
vs = [ Var i | i <- [1 .. n] ]
exactlyOneCorrect :: Int -> Bool
exactlyOneCorrect n =
all (\asn -> satisfies asn cnf == (countTrue n asn == 1)) (allAssignments vs)
where
lits = [ posLit (Var i) | i <- [1 .. n] ]
cnf = CNF (exactlyOne lits)
vs = [ Var i | i <- [1 .. n] ]
atLeastOneShape :: Bool
atLeastOneShape = atLeastOne lits == [lits]
where lits = [ posLit (Var 1), posLit (Var 2), posLit (Var 3) ]
queensSatValid :: Int -> Bool
queensSatValid n = case solveCdcl (queens n) of
CdclSat model -> validQueens n model
CdclUnsat -> False
coloringSatValid :: Int -> Graph -> Bool
coloringSatValid k g = case solveCdcl (coloring k g) of
CdclSat model -> validColoring k g model
CdclUnsat -> False
completeK4 :: Graph
completeK4 = Graph 4 [(1, 2), (1, 3), (1, 4), (2, 3), (2, 4), (3, 4)]
cycleC5 :: Graph
cycleC5 = Graph 5 [(1, 2), (2, 3), (3, 4), (4, 5), (5, 1)]
cycleC6 :: Graph
cycleC6 = Graph 6 [(1, 2), (2, 3), (3, 4), (4, 5), (5, 6), (6, 1)]
bipartite :: Graph
bipartite = Graph 6 [(1, 4), (1, 5), (2, 5), (2, 6), (3, 4), (3, 6)]
sudokuSolvesValid :: [(Int, Int, Int)] -> Bool
sudokuSolvesValid givens = case solveCdcl (sudoku 3 givens) of
CdclSat model -> validSudoku 3 givens model
CdclUnsat -> False
sudokuPuzzle :: [(Int, Int, Int)]
sudokuPuzzle = parseGrid 3 (unlines
[ "530070000"
, "600195000"
, "098000060"
, "800060003"
, "400803001"
, "700020006"
, "060000280"
, "000419005"
, "000080079" ])
modelSetEq :: CNF -> CNF -> Bool
modelSetEq a b =
all (\asn -> satisfies asn a == satisfies asn b) (allAssignments vs)
where vs = nub (allVars a ++ allVars b)
unitPropSound :: CNF -> Bool
unitPropSound cnf = case unitPropagate cnf of
Nothing -> not (bruteForceSat cnf)
Just (units, residual) ->
bruteForceSat cnf == bruteForceSat residual
&& case solveCdcl residual of
CdclSat m -> satisfies (completeModel cnf (reconstruct units m)) cnf
CdclUnsat -> True
pureElimEquisat :: CNF -> Bool
pureElimEquisat cnf =
bruteForceSat cnf == bruteForceSat residual
&& case solveCdcl residual of
CdclSat m -> satisfies (completeModel cnf (reconstruct pures m)) cnf
CdclUnsat -> True
where (pures, residual) = pureLiteralElim cnf
preprocessCorrect :: CNF -> Bool
preprocessCorrect cnf = case preprocess cnf of
Unsatisfiable -> not (bruteForceSat cnf)
Simplified fixed residual ->
bruteForceSat cnf == bruteForceSat residual
&& case solveCdcl residual of
CdclSat m -> satisfies (completeModel cnf (reconstruct fixed m)) cnf
CdclUnsat -> True
dlNegCycle :: DlProblem
dlNegCycle = DlProblem
[DiffAtom 1 2 0, DiffAtom 2 3 0, DiffAtom 3 1 (-1)]
(CNF [[posLit (Var 1)], [posLit (Var 2)], [posLit (Var 3)]])
dlFeasible :: DlProblem
dlFeasible = DlProblem
[DiffAtom 1 2 2, DiffAtom 2 3 3]
(CNF [[posLit (Var 1)], [posLit (Var 2)]])
dlDisjunctive :: DlProblem
dlDisjunctive = DlProblem
[DiffAtom 1 2 (-1), DiffAtom 2 1 (-1)]
(CNF [[posLit (Var 1), posLit (Var 2)]])
dlSatVerified :: DlProblem -> Bool
dlSatVerified prob = case solveDl prob of
DlSat model -> dlModelSatisfies prob model
DlUnsat -> False
dlAgrees :: DlProblem -> Bool
dlAgrees prob =
let brute = dlBruteSat prob
in case solveDl prob of
DlSat model -> brute && dlModelSatisfies prob model
DlUnsat -> not brute
dlBruteSat :: DlProblem -> Bool
dlBruteSat prob =
any (\assignment -> dlModelSatisfies prob (Map.fromList assignment)) (intAssignments vars)
where vars = nub (concatMap (\a -> [dlLhs a, dlRhs a]) (dlAtoms prob))
intAssignments :: [Int] -> [[(Int, Int)]]
intAssignments = go
where
domain = [-6 .. 6]
go [] = [[]]
go (v : vs) = [ (v, d) : rest | d <- domain, rest <- go vs ]
randDlAtom :: Int -> Seed -> (DiffAtom, Seed)
randDlAtom numDlVars s0 =
let (a, s1) = randInt 1 numDlVars s0
(b, s2) = randInt 1 numDlVars s1
(w, s3) = randInt (-2) 2 s2
in (DiffAtom a b w, s3)
randDlLit :: Int -> Seed -> (Lit, Seed)
randDlLit numAtoms s0 =
let (v, s1) = randInt 1 numAtoms s0
(b, s2) = randBool s1
in (Lit (Var v) b, s2)
randDlClause :: Int -> Seed -> (Clause, Seed)
randDlClause numAtoms s0 =
let (len, s1) = randInt 1 2 s0
in genN len (randDlLit numAtoms) s1
randDlProblem :: Seed -> (DlProblem, Seed)
randDlProblem s0 =
let numAtoms = 4
numDlVars = 3
(as, s1) = genN numAtoms (randDlAtom numDlVars) s0
(nc, s2) = randInt 1 5 s1
(cls, s3) = genN nc (randDlClause numAtoms) s2
in (DlProblem as (CNF cls), s3)
randomDlProblems :: [DlProblem]
randomDlProblems = fst (genN 60 randDlProblem 20240828)