=========
Website
https://cvc5.github.io
Documentation
https://cvc5.github.io/docs
System Description
**cvc5: A Versatile and Industrial-Strength SMT Solver.**
Barbosa H., Barrett C., Brain M., Kremer G., Lachnitt H., Mann M., Mohamed A.,
Mohamed M., Niemetz A., Nötzli A., Ozdemir A., Preiner M., Reynolds A., Sheng
Y., Tinelli C., and Zohar Y., TACAS 2022.
[http://dx.doi.org/10.1007/978-3-030-99524-9_24](http://dx.doi.org/10.1007/978-3-030-99524-9_24)
New Features
Streamlined C++ API
Documentation: https://cvc5.github.io/docs/latest/api/cpp/cpp.html
Two new Python language bindings
- Base module: Feature complete with C++ API
- Pythonic module: A pythonic wrapper around the base module
- Documentation: https://cvc5.github.io/docs/latest/api/python/python.html
New Java language bindings
Documentation: https://cvc5.github.io/docs/latest/api/java/java.html
Theory of Bags (Multisets)
A new theory of bags, which are collections that allow duplicates. It
supports basic operators like union disjoint, union max, intersection,
difference subtract, difference remove, duplicate removal, and multiplicity
of an element in a bag.
Theory of Sequences
- A new parametric theory of sequences whose syntax is compatible with the
syntax for sequences used by Z3.
- A new array-inspired procedure (option `--seq-array`).
Arithmetic
Nonlinear real arithmetic is now solved using a new solver based on
cylindrical algebraic coverings. Includes full support for non-rational
models and a number of options `--nl-cov-*` for, e.g., different projection
operators, Lazard's lifting or variable elimination.
The new solver requires the libpoly library, and Lazard's lifting
additionally requires CoCoALib.
Arrays
Added 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`.
Bit-vectors
- New bit-vector solver with CaDiCaL as default SAT back-end.
- New approach for solving bit-vectors as integers (option `--solve-bv-as-int`).
Datatypes
Support for generic datatype updaters `((_ update s) t u)` which replaces
the field specified by selector `s` of `t` by the value `u`.
Integers
- Support for an integer operator `(_ iand n)` that returns the bitwise `and`
of two integers, seen as integers modulo n.
- Support for an integer operator `int.pow2`, used as `(int.pow2 x)` which
represents 2 to the power of x.
Quantifiers
- Improved support for enumerative instantiation (option `--enum-inst`).
- SyGuS-based quantifier instantiation (option `--sygus-inst`).
Strings
- Improved performance using new techniques, including model-based
reductions, eager context-dependent simplification, and equality-based
conflict finding.
- Support for `str.indexof_re(s, r, n)`, which returns the index of the first
occurrence of a regular expression `r` in a string `s` after index `n` or
-1 if `r` does not match a substring after `n`.
Proofs
- Documentation available at:
https://cvc5.github.io/docs/latest/proofs/proofs.html
- When used after an unsatisfiable response to `checkSat`, `getProof`
returns a representation of the refutation proof for the current set of
assertions (get-proof in SMT-LIB).
- Preliminary support for translations to external proof formats LFSC and Alethe.
Difficulty Estimation
The API method `getDifficulty` returns a map from asserted formulas to
integers which estimates how much that formula contributed to the
difficulty of the overall problem (`get-difficulty` in SMT-LIB).
Learned Literals
The API method `getLearnedLiterals` gets a list of literals that are
entailed by the current set of assertions that were learned during solving
(`get-learned-literals` in SMT-LIB).
Abduction and Interpolation
- The API method `getAbduct` can be used to find an abduct for the current set
of assertions and provided goal (get-abduct in SMT-LIB). Optionally, a
SyGuS grammar can be provided to restrict the shape of possible abducts.
If using the text inferace, the grammar may be provided using the same
syntax for grammars as in SyGuS IF format.
- The API method `getInterpolant` can be used to find an interpolant for the
current set of assertions and provided goal (get-interpolant in SMT-LIB).
Like abduction, grammars may be provided to restrict the shape of
interpolants.
Support for Incremental Synthesis Queries
- The core SyGuS solver now supports getting multiple solutions for a
synthesis conjecture via the API. The method `checkSynthNext` finds the
next SyGuS solution to the current set of SyGuS constraints
(`check-synth-next` in SyGuS IF).
- `getAbductNext` finds the next abduct for the current set of
assertions and provided goal (`get-abduct-next` in SMT-LIB).
- `getInterpolantNext` finds the next interpolant for the current set of
assertions and provided goal (`get-interpolant-next` in SMT-LIB).
Pool-based Quantifier Instantiation
- The API method `declarePool` declares symbol sets of terms called pools
(`declare-pool` in SMT-LIB).
- Pools can be used in annotations of quantified formulas for fine grained
control over quantifier instantiations (`:inst-pool`, `:inst-add-to-pool`,
`:skolem-add-to-pool` in SMT-LIB).
Diagnostic Outputs
The option `-o TAG` can be used to enable a class of useful diagnostic
information, such as the state of the input formula before and after
pre-preprocessing, quantifier instantiations, literals learned
during solving, among others. For SyGuS problems, it can be used to
show candidate solutions and grammars that the solver has generated.
Unsat cores
- Production modes based on the new proof infrastructure
(`--unsat-cores-mode=sat-proof`) and on the solving-under-assumption
feature of Minisat (`--unsat-cores-mode=assumptions`). The mode based on
SAT assumptions + preprocessing proofs is the new default.
- Computing minimal unsat cores (option `--minimal-unsat-cores`).
Blocking Models
- The API method `blockModels` can be used to block the current model using
various policies for how to exclude the values of terms (`block-model` in
SMT-LIB).
- The API method `blockModelValues` can be used to block the current model
for a provided set of terms (`block-model-values` in SMT-LIB).
Model Cores
- The API method `isModelCoreSymbol` can be used to query whether the value
for a symbol was critical to whether the model satisfies the current set of
assertions.
- Models can be limited to show only model core symbols (option `--model-cores`).
Changes
* CaDiCaL and SymFPU are now required dependencies. CaDiCaL 1.4.1 is now the
version used by default.
* Options have been extensively refactored, please refer to the cvc5
documentation for further information.
* Removed support for the CVC language.
* SyGuS: Removed support for SyGuS-IF 1.0.
* Removed support for the (non-standard) `define` command.
* Removed the legacy API along with the Java and Python bindings for it.
* Interactive shell: the GPL-licensed Readline library has been replaced the
BSD-licensed Editline. Compiling with `--best` now enables Editline, instead
of Readline. Without selecting optional GPL components, Editline-enabled cvc5
builds will be BSD licensed.
* The `competition` build type includes the dependencies used for SMT-COMP by
default. Note that this makes this build type produce GPL-licensed binaries.
* Bit-vector operator `bvxnor` was previously mistakenly marked as
left-assoicative in SMT-LIB. This has recently been corrected in SMT-LIB. We
now restrict `bvxnor` to only allow two operands in order to avoid confusion
about the semantics, since the behavior of n-ary operands to `bvxnor` is now
undefined in SMT-LIB.
* SMT-LIB output for `get-model` command now conforms with the standard,
and does *not* begin with the keyword `model`. The output
is the same as before, only with this word removed from the beginning.
* Building with Python 2 is now deprecated.
* The SMT-LIB syntax for some extensions has been changed. Notably, set
operators are now prefixed by `set.`, and relations by `rel.`. For example,
`union` is now written `set.union`.
* Removed support for redundant logics `ALL_SUPPORTED` and `QF_ALL_SUPPORTED`,
use `ALL` and `QF_ALL` instead.