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Changes the assertion that checks for the maximum cardinality of set models to an exception, following #4374.
Also cleans up the code around it: previously, the Rational was checked against LONG_MAX, converted to std::uint32_t and then stored into an unsigned. Now we use std::uint32_t all the way.
Fixes #4374.
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In preparation of removing the old proof module, this commit changes the
regression runner to not add the flag --check-proofs anymore when
running the regressions.
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Calling (reset) multiple times produced parsing problems (#4866) and could probably lead to all kinds of interesting issues.
In a nutshell, reset() failed to properly reset d_initialOptions (which is used to properly reset d_options) so that all options defaulted after the second call to reset().
This PR properly sets d_initialOptions after a reset (and the filename as well).
Fixes #4866.
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Fixes #4790.
Fixes two bugs in the decision tree learning solver for sygus, one involving evaluation of "templated" enumerators, and one involving ITE strategies where child types are different than the root.
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Fixes regress1.
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We have had a few issues where essentially users misinterpreted the error message about which types of exponents are supported for (^ base exp). Given that this is rewritten to a multiplication of length exp, we only support reasonably small natural numbers.
This PR improves the error message.
Fixes #4692
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Fixes #4820. The performance issue was caused by
0988217562006d3f59e01dc261f39121df6d75f5. That commit introduced an
option (`--strings-len-conc`) that optionally moves the length
constraint for skolems to the conclusion of an inference instead of
making it part of the term registration. However, for
`DEQ_DISL_STRINGS_SPLIT`, we were only asserting that `LENGTH_GEQ_ONE`
in the case where this option was not enabled, instead of asserting that
the length of the skolem is equal to the component on the other side of
the disequality. This lead to an infinite loop of inferences because we
effectively were just splitting a component into two skolems and the
only restriction was that the first one was non-empty. We guessed the
second skolem to be empty, so the first skolem was equal to the
component, the skolem was marked congruent, and we ended up with the
same normal form as before.
The commit fixes the issue by adding an argument to
`getDecomposeConclusion()` that specifies whether to add the length
constraint or not. This option is used to always add the length
constraint in the case of `DEQ_DISL_STRINGS_SPLIT`.
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Fixes #4701. That benchmark now times out.
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Fixes #4759 .
Also refactors this method.
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This PR adds support for seq.nth operator by eliminating it during expandDefinitions, based on sub-sequences.
Tests that use this operator are also included.
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The current arith proof machinery can prove conflicts which are
explained by assumptions and tightened assumptions.
Previously we verified that the conflict constraint was explained in
terms of assumptions and tightened assumptions, before trying to
save/produce a proof.
We did not verify that the negated constraint was an assumption or
tightened assumption.
This caused us to attempt to prove conflicts around constraints whose
negations where proven by general means (in the case of #4714, by the
equality engine), which the proof machinery was not prepared to handle.
This PR also checks that the negate constraint is an assumption or
tightened assumption, before saving the proof.
Thanks, Gereon, for doing the initial investigation into this!
fixes 4714
Co-authored-by: Gereon Kremer <nafur42@gmail.com>
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This regression output was unexpected previously since conflict-based instantiation caught a conflict early, this makes it so that the output of this regression should be deterministic.
Fixes regress1.
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This prints # instantiations per round (during solving) for each quantified formula with `--debug-inst`, giving output like this:
```
(num-instantiations myQuant1 1)
(num-instantiations myQuant2 1)
unsat
```
It also changes the default value of print-inst-full to match the behavior of unsat-cores vs unsat-cores-full (by default, nameless quantifiers are ignored).
It fixes an issue with qid, where mkVar was accidentally used instead of mkConst, leading to assertion failures in debug. Marking major since this fixes debug regress1.
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Commit 64a7db86206aa0993f75446a3e7f77f3c0c023c6 introduced a caching
mechanism in `TheoryEngine::getExplanation()`. However, there seem to be
issues related to the timestamps of the explanations. This commit fixes
the issue by making the timestamp part of the cache. The change ensures
that explanations for a certain node never rely on other explanations
for that node with a later timestamp.
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This makes an option --debug-sygus available to the user for tracing the sygus solver. For the classic max2 example the option is:
(sygus-enum 0)
(sygus-candidate (max 0))
(sygus-enum 0)
(sygus-enum 1)
(sygus-enum x)
(sygus-enum x)
(sygus-candidate (max x))
(sygus-enum x)
(sygus-enum y)
(sygus-enum y)
(sygus-candidate (max y))
(sygus-enum y)
(sygus-enum (+ x x))
(sygus-enum (+ x 1))
(sygus-enum (+ 1 1))
...
(sygus-enum (ite (<= x y) y 1))
(sygus-candidate (max (ite (<= x y) y 1)))
(sygus-enum (ite (<= x y) y 1))
(sygus-enum (ite (<= x y) y x))
(sygus-enum (ite (<= x y) y x))
(sygus-enum (ite (<= x y) y x))
(sygus-candidate (max (ite (<= x y) y x)))
unsat
(define-fun max ((x Int) (y Int)) Int (ite (<= x y) y x))
Where sygus-enum denotes enumerated terms and sygus-candidate is one that passes a CEGIS refinement check.
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This adds a new print format for instantiations --print-instantiations=num, which prints the total number of instantations of quantified formulas. This count is user-context-dependent, which is in sync with the existing print-instantiation format (list).
It also simplifies and improves printing of Instantiation Tries.
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This adds basic support for string/sequence updating, which has a semantics that is length preserving.
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This PR changes --solve-bv-as-int from a numerical option (specifying the granularity) to an enum (specifying the approach). Currently we support only two modes: OFF and SUM. Future PRs will add more modes.
The numerical value of the granularity is now captured by the new option --bvand-integer-granularity.
Tests are updated accordingly.
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Fixes #4685.
A recent commit #4661 added assertions for checking whether a witness rewrite corresponded to a legal elimination. #4685 demonstrates that these assertions can be violated and hence should be checked to ensure the rewrite is sound.
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Fixes a timeout in the nightlies.
One regression times out during unsat core checking. This appears to be random, the subcall to check for unsat-cores is applying sygus-inst in the expected way, however, it struggles to find the right instances.
Furthermore note that we are planning to redo implementation of unsat cores soon (when proof-new is fully merged), so we should revisit this (and all other) regressions with --no-check-unsat-cores when that happens.
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This PR decouples Options from NodeManager. Instead, options now live in SmtEngine.
The changes that were required for this PR include:
The main internal options object is now owned by SmtEngine instead of ExprManager.
The ownership resource manager is moved from NodeManager to SmtEngine.
Node manager listeners are deleted, timeouts and resource limits are set during SmtEngine::finishInit.
A temporary hack was added to make the last constructed SmtEngine to be the one in scope. This ensures that options are in scope whenever an SmtEngine is created.
The methods for invoking "subsolvers" (theory/smt_engine_subsolver.h,cpp) was simplified, as versions of these calls that change options do not have to clone a new copy of the ExprManager anymore.
Resource manager was removed from the smt2 parser.
Minor refactoring was done in SmtEngine to copy "original options" so that options are restored to their state after parsing command line options on reset.
Updates to unit tests to ensure conformance to new options scoping.
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With this PR, we now support a preliminary draft of a theory of sequences.
This PR adds front end support for sequences in the smt2 parser, in the new API, adds regressions and unit tests for them.
As discussed offline, many of the string kinds are given a sequence version in the external API, but not in the internal one. This means that a special case for such kinds, getKindHelper was added to Term.
We do not yet support proper smt2 printing of sequences, which will require access to this code for Kind conversions (to distinguish e.g. str.++ from seq.++).
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Fixes #4674.
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fmfBound (#4673)
There was a strategy in place for alternating which rounds quantifier instantiation would run on when --fmf-bound is enabled.
However, this made it so that in some cases, no instantiation strategy would be applied, if e.g. fmfBound was enabled but no quantified formulas were handled by that strategy.
It is not clear if this strategy is a good idea, considering all use cases of quantifiers, and hence this PR deletes this block of code.
This makes it so that several eqrange benchmarks are answered "unsat" quickly.
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There were two issues related to RE in bodies of re.* that accepted the empty string that led to non-termination in the rewriter for regular expressions.
This also improves trace messages for simpleRegExpConsume.
Fixes #4662.
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Fixes #4644. This commit fixes an issue where the set `d_unconstrained`
in the unconstrained simplification pass was not computed correctly. The
problem was that visiting the same term multiple times did not remove
the variables appearing in that term from the visited-once set. A simple
example that triggers the issue is the following:
```
(set-logic ALL)
(declare-fun a () Bool)
(declare-fun b () Bool)
(assert (not (= a b)))
(assert (= a (= a b)))
(check-sat)
```
After running `UnconstrainedSimplifier::visitAll()` on both assertions,
we end up with `[b]` as our `d_unconstrained` set. We end up inferring
the substitution `(= a b) --> b` and get `(not b)` and `b`, which is
unsat even though the original problem is sat.
This commit fixes the issue by visiting all the children of a node if we
visit a node for a second time. This makes sure that we remove any
children from the visisted-once set.
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This commit adds support for an eqrange predicate. (eqrange a b i j) is true if arrays a and b are equal on all indices within indices i and j, i.e., \forall k . i <= k <= j --> a[k] = b[k]. Requires option --arrays-exp to be enabled.
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Fixes #4636.
This adds transcendental function kinds to the list of unevaluated operators (operators that don't necessarily rewrite to constants when applied to constant children). One consequence of this is that when models are enabled, we cannot solve for equations like (= a (cos b)), since the value of (cos b) is not necessarily evaluable, and hence must be approximated. As a result, we answer the benchmark on #4636 instead of generating an incorrect model (when models are enabled). When models are disabled, we answer "sat". A regression had a similar issue which happened to be succeeding. I've added --no-check-models to this regression (or otherwise we would answer unknown for this benchmark).
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fix 1:
------
The wrong flag was checked in the traversal, causing an assertion error [here](https://github.com/CVC4/CVC4/blob/8236d7f9bff3aef4f7b37a15d509b8a11551401f/src/preprocessing/passes/bv_to_int.cpp#L247)
This is fixed in this PR. A test was added as well.
fix 2:
------
It is desirable that bv-to-bool runs before bv-to-int, but this was not the case, and is fixed in this PR.
Do not merge until after competition release (label added).
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This commit adds a logic check for `define-fun-rec`/`define-funs-rec` at
the level of the new API that checks whether the logic is quantified and
includes UF. To make sure that the parser actually executes that check,
this commit converts the `DefineFunctionRecCommand` command to use the
new API instead of the old one. This temporarily breaks the `exportTo`
functionality for `DefineFunctionRecCommand` but this is not currently
used within the CVC4 code base (and it seems unlikely that users use
commands).
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Fixes #4620.
The extended rewrite (and A B) ---> (and A (B * { A -> true } ) triggers an unsoundness when B contains witness terms. More generally, contextual substitution into witness terms is unsound since the skolemization of witness terms is added globally whereas the substitution corresponds to a fact that holds locally. This means that A -> true above may be added as a global constraint indirectly through witness skolemization.
A general example of this unsoundness:
(or (and (>= x 0) (P (witness ((z Int)) (=> (>= x 0) (= (* z z) x))))) F)
rewrites to
(or (and (>= x 0) (P (witness ((z Int)) (= (* z z) x)))) F)
preprocesses to
(and (or (and (>= x 0) (P k)) F) (= (* k k) x))
which now implies that (>= x 0) by the last conjunct, whereas this was not implied in the original formula
This PR limits the kinds that can be traversed when applying substitutions in the extended rewriter, including from the rewrite above. In particular, the fix ensures that the partialSubstitute method is used in the extended rewriter when applicable, which now explicitly disallows recursion on WITNESS.
Notice that this fixes contextual substitutions in the extended rewriter, but does not fix the more general issue. In particular, we still should be careful to check if contextual substitutions are applied by any other preprocessing passes.
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This changes the grammar construction in the case of anyterm + polynomial grammar so that the binary predicates EQUAL and LEQ are changed to unary predicates lambda x : ANYTERM. P(x, ZERO) rather than lambda xy. P(ANYTERM, ANYTERM), in which ZERO is a 0 constant of the respective type. Currently integer and bit-vectors are supported for this transformation.
This avoid enumerating spurious terms and can lead to significant improvements in enumeration (although not necessarily in solving speed given the current unstable nature of ANYTERM usage).
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Fixes #4076.
In the lazy bit-blaster, when querying the equality status, if the SAT
solver has a full model, it is queried for the model values of the
operands of the equality. However, the check if the bit-blaster has a
full model did not consider the case where no assertions have yet been
added, which leads to querying values of bits that are still unassigned
in the SAT solver.
Co-authored-by: <mathias.preiner@gmail.com>
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Fixes #4075.
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Fixes #4130.
This further makes an attempt at more consistent error printing.
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The RE derive inference was not designed to handle re.comp. This makes the application of this inference more conservative.
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This option only marginally helped and will be difficult to support with the new proof infrastructure.
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This commit adds support for the last remaining string operators from
the new SMT-LIB standard for the theory of strings. The commit adds the
kinds, type checking, reductions, and evaluation rewrites for
`str.replace_re` and `str.replace_re_all`.
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Fixes #4576. ASan was reporting memory leaks because the skolem manager
was being destroyed after the attributes and zombies were already
cleaned up in the destructor of NodeManager. This commit changes the
destruction order to ensure that the skolem manager is destroyed before
the rest of the cleanup.
Note: this issue did not only make the benchmark in #4576 fail but
several tests in our regressions.
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Fixes #4552. Fixes #4555. The SMT-LIB standard mandates that definitions
are kept when `:global-declarations` are enabled. Until now, CVC4 was
keeping track of the symbols of a definition correctly but lost the body
of the definition when the user context was popped. This commit fixes
the issue by adding a `global` parameter to
`SmtEngine::defineFunction()` and `SmtEngine::defineFunctionRec()`. If
that parameter is set, the definitions of functions are added at level 0
to `d_definedFunctions` and the lemmas for recursive function
definitions are kept in an additional list and asserted during each
`checkSat` call. The commit also updates new API, the commands, and the
parsers to reflect this change.
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Also includes some minor improvement to expand definitions in TheoryDatatypes leftover from the branch.
Adds 3 regressions using the option --dt-nested-rec.
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Fixes nightlies. Competition builds do not report parsing errors like
other builds. As a result, one of the regression tests that is testing
for parse errors was failing for competition builds. In this particular
example, we just report `unknown`. This commit marks the regression to
be skipped for competition builds.
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Fixes #4446. This commit fixes two issues related to the handling of
Boolean term variables:
Removing Boolean subterms and replacing them with a Boolean term
variable introduces an equality of the form (= v t) where v is the
Boolean term variable and t is the term. It is important that these
equalities do not get removed. This commit changes
Theory::isLegalElimination() to take this into account.
The incorrect model reported in the issue was caused by some of the
Boolean term variables not being assigned values by the SAT solver
when we decided that the benchmark is satisfiable. Our justification
heuristic (correctly) decided that it is enough to satisfy one of the
disjuncts in the assertion to satisfy the whole assertion. However,
the assignments that we received from the SAT solver restricted us to
pick a specific value for one of the Boolean constants:
Literal | Value | Expr
---------------------------------------------------------
'7 ' 0 c
'0 ' 1 true
'1 ' 0 false
'2 ' 0 (a BOOLEAN_TERM_VARIABLE_274)
'5 ' _ b
'3 ' 1 (a BOOLEAN_TERM_VARIABLE_277)
'4 ' _ BOOLEAN_TERM_VARIABLE_274
'6 ' 0 BOOLEAN_TERM_VARIABLE_277
This meant that we had to pick true for BOOLEAN_TERM_VARIABLE_274
but we picked false since we simply treated it as an unassigned
variable. In general, the justification heuristic handles embedded
skolems introduced by term removal first and asks the SAT solver to
decide on Boolean term variables. However, for some logics, such as
QF_AUFLIA, we use the justification heuristic not for decisions but
only to decide when to stop, so those decisions were not done. This
commit introduces a conservative fix that adds a check after
satsifying all the assertions that makes sure that the equalities
introduced for Boolean terms are satisfied as well. Due to the eager
treatment of Boolean term variables when we use the justification
heuristic also for decisions, it is likely that we don't really have
the problem in that case but it doesn't hurt to enable the fix. It is
also possible that this fix is only required with models but it is
definitely safer to just always enable it (there could be tricky
corner cases involving the theory combination between UF and Boolean
terms). Additionally, this commit changes the ITE-specific naming in
the justification heuristic to reflect more accurately that we are in
general dealing with skolems introduced by term removals and not only
due to ITE removal.
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Previously we were treating constructor/selector/tester symbols as arguments to the abduct-to-synthesize.
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