Skip to content

Releases: pysmt/pysmt

0.9.5: 2022-05-28 -- 2 years of bugfixes

Choose a tag to compare

Intermediate release that collects 2 years of bugfixes and improvements.

Python 2 was deprecated in version 0.9.0, and this version removes the use of compatible code for that version.

What's Changed

  • Add support for boolean-typed array in the AtomsOracle by @mikand in #644
  • Switched from nosetests to pytest by @mikand in #662
  • Fixed a bug in yices quantifier support and added regression test by @mikand in #657
  • Fix Boolector install script by @4tXJ7f in #656
  • BUG: define UFNIA as logic with integer arithmetic by @johnyf in #659
  • Handling of algebraic constants in simplify by @EnricoMagnago in #658
  • Integer div by @EnricoMagnago in #667
  • Fix CVC4 installation on macOS by @kammoh in #666
  • Bug in times distributor by @EnricoMagnago in #671
  • Fixed reset_assertion method for incremental-tracking solvers by @mikand in #672
  • Minor Corrections by @mfarif in #673
  • implement add_assertions method for solver. by @EnricoMagnago in #679
  • Fix "get_model" when called from a generic solver (Fix #674) by @btwael in #675
  • Remove six and python 2 compatibility code by @marcogario in #684
  • Added fallback to Swig3 to address as much as possible issue #682 by @mikand in #685
  • Fix to correctly pass logic to solvers started by Portfolio by @ekilmer in #683
  • SmtLib model validation support by @mikand in #681
  • Fix iss694 by @EnricoMagnago in #695
  • Fixed CVC4 installer after upstream repository renaming by @mikand in #697
  • Remove call to FNode.substitute in SmtLibExecutionCache by @EnricoMagnago in #699
  • Added printing of annotations to smt lib printers by @agirardi-fbk in #703
  • Integer div by @EnricoMagnago in #705
  • Updated docker images to solve deprecation issue on azure pipelines by @mikand in #706
  • Workaround to fix Z3 segfault by @mikand in #713
  • Add possibility to use several BV operators as left associative by @agirardi-fbk in #714
  • Fixed issue #613 by @mikand in #710

New Contributors

Full Changelog: v0.9.0...v0.9.5

0.9.0: 2020-04-26 -- PySMT as module

Choose a tag to compare


  • PySMT as module (PR #573): It is now possible to do

    python -m pysmt install


    python -m pysmt shell

    while the tool pystm-install is still available, using the module syntax makes it easier to understand which version of python will be used, in case multiple interpreters co-exist.

  • Added functions to obtain the symbols in SMTLIB script (PR #583)

  • Python 2 is not supported anymore. While it might still work, we will not actively test for it anymore.


  • Boolector: Incremental and Unsat cores support (PR #591, #567). Thanks Makai Mann for providing the patch.

  • Picosat: Fixed a bug related to solver reset (PR #567)

  • Boolector: Upgrade to 3.2.1

  • MathSAT: Upgrade to 5.6.1


  • fix deprecation warning (PR #574, PR #562). Thanks to Liana Hadarean and Caleb Donovick.

  • PysmtSyntaxError: Fix missing message constructor (PR #576). Thanks to Liana Hadarean for providing a fix.

  • Version: Static version in (PR #575)

  • Fix simplifier StrIndexOf capitalization (PR #563). Thanks to Makai Mann for providing the patch.

  • Sort the arguments of Times while simplifying (PR #561). Thanks to Ahmed Irfan for providing the patch.

  • Fix bug in deque pop in smtlib/parser (PR #558). Thanks to Sebastiano Mariani for providing the patch.

  • Function names quoted with ' instead of | when seraializing to smt2 (PR #584). Thanks Kevin Laeufer for reporting this.

  • Fix assertion tracking for boolector (PR #589). Thanks Makai Mann for providing the patch.

  • Handle one-bit shifts in btor (PR #592) Thanks Makai Mann for providing the patch.

  • Fix issue with bv conversion in Yices (PR #597). Thanks to @nano-o for reporting this.

  • Fix Mathsat signature for BV_CONCAT (PR #598). Thanks Makai Mann for providing the patch.

  • Support n-ary BVConcat (PR #621). Thanks to Ridwan Shariffdeen for reporting this.

  • Fix a correctness issue when reading from SMT-LIB interface (Issue #616, #615, PR #619). Thanks to Sergio Mover for reporting this.

  • Clear pending assertions in IncrementalTrackingSolver.assertions (PR #627). Thanks to Enrico Magnago for reporting this.

  • Various documentation fixes. Thanks to Matthew Fernandez, Guillem Francès, and Gianluca Redondi.

  • Disable multiprocessing in script (PR #637). Thanks Patrick Trentin for reporting this.

0.8.0: Better Install and Great Community

Choose a tag to compare


Disabled support for interpolation in Z3, since this is not available anymore up-stream

Deprecation Warning:

This release is the last release to support Python 2.7. Starting from 0.9.0 only Python 3+ will be supported.


  • Solver installation within site-package (PR #517). pysmt-install now installs the solvers within the site-package directory (by default). This makes it possible to work with virtual environments, and does not require anymore to export the Python path, greatly simplifying the installation process. Thanks to Radomi Stevanovic for contributing the patch.

  • Simplify shared lib usage (PR #494): Modify z3 and msat installers in order to make their shared binary objects (libraries/dlls) auto-discoverable, without the need for setting LD_LIBRARY_PATH/PATH. Thanks to Radomir Stevanovic for contributing the patch.

  • BV Simplification (PR #531): Multiple improvements on the simplification of BV expressions. Thanks to Haozhong Zhang for contributing the patch.

  • Ackermannization (PR #515): Add support for Ackermannization in pysmt.rewritings. Thanks to Yoni Zohar for contributing the patch.

  • FNode.bv_str: Multiple format for BV printing (PR #468)

  • Examples (PR #507): Extend model_checking example with PDR. Thanks to Cristian Mattarei for contributing the patch.

  • Docs: Tutorial on basic boolean solving (PR #535)

  • Tests: Removed old warning and other clean-ups (PR #532, #512)

  • Warnings (PR #497): Importing pysmt.shortcuts will only raise warnings within pySMT, instead of all warnings from external libraries.

  • Examples (PR #541): Add example for the theory of Strings

  • Top-Level Propagator (PR #544): Add a basic toplevel-propagation functionality to propagate definitions of the form: variable = constant, variable = variable, constant = constant . Thanks to Ahmed Irfan for providing this feature.

  • Clean-up debug print from SMT parser (PR #543): Thanks to Ahmed Irfan for providing this patch.


  • Yices: Upgrade to 2.6.0 (PR #509).

  • Boolector: Upgrade to 3.0.1-pre (7f5d32) (PR #514)

  • CVC4: Upgrade to 1.7-prerelease (PR #552)
    Known issue: Passing options to CVC4 fails sometimes.

  • Z3: Upgrade to 4.8.4 (PR #550).
    Removed support for interpolation.
    Known issue: Some tests on use of tactics exhibit some random failures on Travis.

  • Yices: Add support for OSX (PR #486). Thanks to Varun Patro for contributing the patch.

  • SMTLIB Solver (PR #524): Add support for custom sorts in SMT-LIB interface. Thanks to Yoni Zohar for contributing the patch.

  • MathSAT (PR #526): Add option to support preferred variables with polarity. Thanks to Cristian Mattarei for providing the patch.


  • SmtLib parser (PR #521): Fix StopIteration error. The error would make it impossible to use the parser with Python 3.7. The fix changes the structure of the parser, in order to separate cases in which we know that there is a token to consume (function consume) and when we want to consume a token only if available (function
    consume_maybe). Thanks to @samuelkolb and Kangjing Huang for reporting this.

  • Boolector: Fixed bug in LShl and LShr conversion (PR #534)

  • Z3 (PR #530, #528): Fixed race condition during context deletion. The race condition would cause pySMT to segfault on certain situations. Thanks to Haozhong Zhang for helping us reproduce the issue and to @Johanvdberg for reporting it.

  • MathSAT (PR #518): Fix installation error on darwin. Thanks to Lenny Truong for contributing the patch.

  • Fix declare-sort bug (PR #501). Thanks to Yoni Zohar for contributing the patch.

  • Fix docstring for BVAShr (PR #503). Thanks to Mathias Preiner for contributing the patch.

  • Fix yices compilation on OSX without AVX2 instruction (PR #491)

  • Fix PysmtTypeError when reusing symbols in SMT-LIB define-fun (PR #502). Thanks to Yoni Zohar for contributing the patch.

  • Fix doublequote escaping (PR #489). Thanks to Lukas Dresel for contributing the patch.

  • Fix pySMT CLI for Python3 (PR #493). Thanks to Radomir Stevanovic for contributing the patch.

0.7.5: Strings and Cython Parser

Choose a tag to compare


  • Strings Theory (#458)

    Add support for the theory of Strings as supported by CVC4.

    Direct solver support is limited to CVC4, but the SMT-LIB interface
    can be used to integrate with other solvers (e.g., Z3).

    This feature was largely implemented by Suresh Goduguluru and
    motivated by Clark Barrett.

  • SMT-LIB Parser: Improved performance with Cython (PR #432)

    The SMT-LIB parser module is now compiled using Cython behind the
    scenes. By default pySMT will try to use the cython version but the
    behavior can be controlled via env variables::

    PYSMT_CYTHON=False # disable Cython
    PYSMT_CYTHON=True # force Cython: Raises an error if cython or the
    # SMT-LIB parser module are not available.
    unset PYSMT_CYTHON # defaults to Cython but silently falls back to
    #pure-python version

    The API of pysmt.smtlib.parser does not change and preserves
    compatibility with previous versions.

    Benchmarking on shows: ::

    $ PYSMT_CYTHON=True python3.5 --count 500
    The mean execution time was 2.34 seconds
    The max execution time was 59.77 seconds

    $ PYSMT_CYTHON=False python3.5 --count 500
    The mean execution time was 3.39 seconds
    The max execution time was 85.46 seconds

  • SMT-LIB Parser: Added Debugging Information (Line/Col number) (PR #430)

  • pysmt-install: Simplified solver version check (PR #431)

  • Extended infix notation to support:

    • Store and Select (PR #437)
    • NotEquals (PR #438)
    • EUF Function application (PR #445)
  • Examples: Quantifier Elimination in LRA (PR #447)

  • Sorts: Stronger type checking for composite sorts (PR #449)

  • BvToNatural: Introduced new operator to convert bitvectors into
    natural numbers (PR #450)

  • Examples: Theory Combination (PR #451)

  • QE: Introduce new QE techniques based on Self-Substitution (PR #460)


  • Z3: Upgrade to 4.5.1 dev (082936bca6fb) (PR #407)

  • CVC4: Upgrade to 1.5 (PR #424)

  • MathSAT: Upgrade to 5.5.1 (PR #453)

  • MathSAT: Add Windows Support (PR #453)


  • Support for Theory of Strings (SMT-LIB + CVC4) (PR #458)


  • Z3: Conversion of top-level ITE (PR #433)

  • Z3: Fixed exception handling (PR #473): Thanks to Bradley Ellert
    for reporting this.

  • Detect BV type in Array and Function when using infix notation (PR #436)

  • Support GMPY objects in BV construction (PR #441)

  • SMT-LIB: Fixed parsing of #x BV constants (PR #443): Thanks to
    @cdmcdonell for reporting this.

  • SMT-LIB: Remove trailing whitespace from bvrol and bvsext (PR #459)

  • Fixed type-checking of Equals, LT and LE (PR #452)

  • Examples: Revised Einstein example (PR #448): Thanks to Saul
    for reporting the issue.

  • Examples: Fixed indexing and simple path condition in MC example (PR
    454): Thanks to Cristian Mattarei for contributing this patch.

  • Fixed installer for picosat to use HTTPS (PR #481)

0.7.0: 2017-08-12 -- Class Based Walkers and Sorts

Choose a tag to compare


  • Removed option "quantified" in Solver (PR #377)
  • Removed deprecated CNFizer.printer method (PR #359)


  • Class-Based Walkers (PR #359):

    Walkers behavior is now defined in the class definition. Processing an AND node always calls walk_and. This makes it possible to subclass and override methods, but at the same time call the
    implementation of a super class, e.g.:

       def walk_and(...):
            return ParentWalker.walk_and(self, ....)

    The utility method Walker.super is provided to automatically handle the dispatch of a node to the correct walk_* function, e.g.,:

      def walk_bool_to_bool(...):
          return ParentWalker._super(self, ....)

    The method Walker.set_functions is deprecated, but kept for compatibility with old-style walkers. Using set_functions has the same effect as before. However, you cannot modify a subclass of a walker
    using set_functions. You should not be using set_functions anymore!

    The method Walker.set_handler is used to perform the same operation of set_function at the class level. The associated decorator @handles can be used to associate methods with nodetypes.

    These changes make it possible to extend the walkers from outside pySMT, without relying on hacks like the Dynamic Walker Factory (DWF). See examples/ for a detailed example.

  • Introduce the support for custom sorts (PySMTTypes) (PR #375)

    Two new classes are introduced: _Type and PartialType

    PartialType is used to represent the concept of SMT-LIB "define-sort". The class _TypeDecl is used to represents a Type declaration, and as such cannot be used directly to instantiate a Symbol. This capture the semantics of declare-sort. A wrapper Type() is given to simplify its use, and making 0-arity sorts a special case. The following two statements are equivalent:

      Type("Colors", 0)

    0-ary type are instantiated by default. For n-ary types, the type needs to be instantiated. This can be done with the method TypeManager.get_type_instance or by using infix notation (if enabled):

      type_manager.get_type_instance(Type(Pair, 2), Int, Int))
      Type(Pair, 2)(Int, Int)

    Type declarations and Type instances are memoized in the environment, and suitable shortucts have been introduced. Logics definition has been extended with the field custom_types to detect the use of custom types. Note: Due to the limited support of custom types by solvers, by default every SMT-LIB logic
    is defined with custom_types=False.

  • Add shortcuts.to_smtlib() to easily dump an SMT-LIB formula

  • Add explicit support for BV and UFBV logics (PR #423): Thanks to Alexey Ignatiev for reporting this.


  • PicoSAT: Upgrade to 965 (PR #425)
  • Boolector: Upgrade to 2.4.1 (PR #422)
  • CVC4: Fixed memory-leak (PR #419)
  • Yices: Upgrade to 2.5.2 (PR #426)


  • Fixed assumption handling in the Boolector wrapper. Thanks to Alexey Ignatiev for contributing with this patch!
  • Fix cyclic imports (PR #406). Thanks to @rene-rex for reporting this.
  • Fixed SMT-LIB Script serialization to default to a daggified representation. (PR #418)
  • Fixed SMT-LIB Parsing of declare-const . Thanks to Ahmed Irfan for reporting this. (PR #429)
  • Fixed logic detection when calling is_unsat (PR #428)

0.6.1: 2016-12-02 -- Portfolio and Coverage

Choose a tag to compare


  • Portfolio Solver (PR #284):

    Created Portfolio class that uses multiprocessing to solve the
    problem using multiple solvers. get_value and get_model work after a
    SAT query. Other artifacts (unsat-core, interpolants) are not
    Factory.is_* methods have been extended to include portfolio
    key-word, and exported as is_* shortcuts. The syntax becomes:

    is_sat(f, portfolio=["s1", "s2"])
  • Coverage has been significantly improved, thus giving raise to some
    clean-up of the tests and minor bug fixes. Thanks to
    for providing free coverage analysis. (PR #353, PR #358, PR #372)

  • Introduce PysmtException, from which all exceptions must
    inherit. This also introduces hybrid exceptions that inherit both
    from the Standard Library and from PysmtException (i.e.,
    PysmtValueError). Thanks to Alberto Griggio for
    suggesting this change. (PR #365)

  • Windows: Add support for installing Z3. Thanks to Samuele
    for contributing this patch. (PR #385)

  • Arrays: Improved efficiency of array_value_get (PR #357)

  • Documentation: Thanks to the Hacktoberfest for sponsoring these

    • Every function in now has a docstring! Thanks to
      Vijay Raghavan for contributing this patch. (PR #363)
    • Contributing information has been moved to the official
      documentation and prettyfied! Thanks to Jason Taylor Hodge for
      contributing this patch. (PR #339)
    • Add link to Google Group in . Thanks to @ankit01ojha for
      contributing this. (PR #345)
  • smtlibscript_from_formula(): Allow the user to specify a custom
    logic. Thanks to Alberto Griggio for contributing this
    patch. (PR #360)


  • MathSAT: Improve back-conversion performance by using MSAT_TAGS (PR #379)
  • MathSAT: Add LIA support for Quantifier Elimination
  • Removed: Solver.declare_variable and Solver.set_options (PR #369,
    PR #378)


  • CVC4:
    • Enforce BV Division by 0 to return a known value (0xFF) (PR #351)
    • Force absolute import of CVC4. Thanks to Alexey Ignatiev
      (@2sev) for reporting this issue. (PR #382)
  • MathSAT: Thanks to Alberto Griggio for contributing these patches
    • Fix assertions about arity of BV sign/zero extend ops. (PR #350, PR #351)
    • Report the error message generated by MathSAT when raising a
      SolverReturnedUnknownResultError (PR #355)
  • Enforce a single call to is_sat in non-incremental mode (PR
    #368). Thanks to @colinmorris for pointing out this issue.
  • Clarified Installation section and added example of call to pysmt-install --env. Thanks to Marco Roveri
    (@marcoroveri) for pointing this out.
  • SMT-LIB Parser:
    • Minor fixes highlighted by fuzzer (PR #376)
    • Fixed annotations parsing according to SMTLib rules (PR #374)
  • pysmt-install: Gracefully fail if GIT is not installed (PR #390)
    Thanks to Alberto Griggio for reporting this.
  • Removed dependency from internet connections when checking picosat
    version (PR #386)

0.6.0: 2016-10-09 -- GMPY2 and Goodbye Recursion

Choose a tag to compare


  • Integer, Fraction and Numerals are now defined in pysmt.constants
    (see below for details). The breaking changes are:

    • Users should use pysmt.constants.Fraction, if they want to
      guarantee that the same type is being used (different types are
      automatically converted);
    • Methods from pysmt.utils moved to pysmt.constants;
    • Numerals class was moved from pysmt.numeral (that does not exist
  • Non-Recursive TreeWalker (PR #322)

    Modified TreeWalker to be non-recursive. The algorithm works by
    keeping an explicit stack of the walking functions that are now
    required to be generators
    . See pysmt.printer.HRPrinter for an
    example. This removes the last piece of recursion in pySMT !

  • Times is now an n-ary operator (Issue #297 / PR #304)

    Functions operating on the args of Times (e.g., rewritings) should
    be adjusted accordingly.

  • Simplified module pysmt.parsing into a unique file (PR #301)

    The pysmt.parsing module was originally divided in two files: and These files were removed and the parser
    combined into a unique file. Code importing those modules
    directly needs to be updated.

  • Use solver_options to specify solver-dependent options (PR #338):

    • MathSAT5Solver option 'debugFile' has been removed. Use the
      solver option: "debug_api_call_trace_filename".
    • BddSolver used to have the options as keyword
      arguments (static_ordering, dynamic_reordering etc). This is not
      supported anymore.
  • Removed deprecated methods (PR #332):

    • FNode.get_dependencies (use FNode.get_free_variables)
    • FNode.get_sons (use FNode.get_args)
    • FNode.is_boolean_operator (use FNode.is_bool_op)
    • pysmt.test.skipIfNoSolverAvailable
    • pysmt.randomizer (not used and broken)


  • Support for GMPY2 to represent Fractions (PR #309).

    Usage of GMPY2 can be controlled by setting the env variable
    PYSMT_GMPY to True or False. By default, pySMT tries to use GMPY2 if
    installed, and fallbacks on Python's Fraction otherwise.

  • Constants module: pysmt.constants (PR #309)

    This module provides an abstraction for constants Integer and
    Fraction, supporting different ways of representing them
    internally. Additionally, this module provides several utility

    • is_pysmt_fraction
    • is_pysmt_integer
    • is_python_integer
    • is_python_rational
    • is_python_boolean

    Conversion can be achieved via:

    • pysmt_fraction_from_rational
    • pysmt_integer_from_integer
    • to_python_integer (handle long/int py2/py3 mismatch)
  • Add Version information (Issue #299 / PR #303)

    • pysmt.VERSION : A tuple containing the version information
    • pysmt.version : String representation of VERSION (following PEP 440)
    • pysmt.git_version : A simple function that returns the version including git information. (pysmt-install) and gain a new --version option that
    uses git_version to display the version information.

  • Shortcuts: read_smtlib() and write_smtlib()

  • Docs: Completely Revised the documentation (PR #294)

  • Rewritings: TimesDistributor (PR #302)

    Perform distributivity on an N-ary Times across addition and

  • SizeOracle: Add MEASURE_BOOL_DAG measure (PR #319)

    Measure the Boolean size of the formula. This is equivalent to
    replacing every theory expression with a fresh boolean variable, and
    measuring the DAG size of the formula. This can be used to estimate
    the Boolean complexity of the SMT formula.

  • PYSMT_SOLVERS controls available solvers (Issue #266 / PR #316):

    Using the PYSMT_SOLVER system environment option, it is possible to
    restrict the set of installed solvers that are actually accessible
    to pySMT. For example, setting PYSMT_SOLVER="msat,z3" will limit the
    accessible solvers to msat and z3.

  • Protect FNodeContent.payload access (Issue #291 / PR 310)

    All methods in FNode that access the payload now check that the
    FNode instance is of the correct type, e.g.:

    FNode.symbol_name() checks that FNode.is_symbol()

    This prevents from accessing the payload in a spurious way. Since
    this has an impact on every access to the payload, it has been
    implemented as an assertion, and can be disabled by running the
    interpreter with -O.


  • Z3 Converter Improvements (PR #321):

    • Optimized Conversion to Z3 Solver Forward conversion is 4x faster,
      and 20% more memory efficient, because we work at a lower level
      of the Z3 Python API and do not create intermediate AstRef objects
      anymore. Back conversion is 2x faster because we use a direct
      dispatching method based on the Z3 OP type, instead of the
      big conditional that we were using previously.
    • Add back-conversion via SMT-LIB string buffer.
      Z3Converter.back_via_smtlib() performs back conversion by printing the
      formula as an SMT-LIB string, and parsing it back. For formulas of
      significant size, this can be drastically faster than using the API.
    • Extend back conversion to create new Symbols, if needed. This
      always raise a warning alerting the user that a new symbol is being
      implicitly defined.
  • OSX: Z3 and MathSAT can be installed with pysmt-install (PR #244)

  • MathSAT: Upgrade to 5.3.13 (PR #305)

  • Yices: Upgrade to 2.5.1

  • Better handling of solver options (PR #338):

    Solver constructor takes the optional dictionary solver_options
    of options that are solver dependent. It is thus possible to
    directly pass options to the underlying solver.


  • Fixed: Times back conversion in Z3 was binary not n-ary. Thanks to
    Ahmed Irfan for submitting the patch (PR #340, PR #341)
  • Fixed: Bug in array_value_assigned_values_map, returning the
    incorrect values for an Array constant value. Thanks to
    Daniel Ricardo dos Santos for pointing this out and submitting
    the patch.
  • Fixed: SMT-LIB define-fun serialization (PR #315)
  • Issue #323: Parsing of variables named bvX (PR #326)
  • Issue #292: Installers: Make dependency from pip optional (PR #300)
  • Fixed: Bug in MathSAT's get_unsat_core (PR #331), that could
    lead to an unbounded mutual recursion. Thanks to Ahmed Irfan for
    reporting this (PR #331)

0.5.1: 2016-08-17 -- NIRA and Python 3.5

Choose a tag to compare


  • Non Linear Arithmetic (NRA/NIA): Added support for non-linear, polynomial arithmetic. This thoery is currently supported only by Z3. (PR #282)
    • New operator POW and DIV
    • LIRA Solvers not supporting Non-Linear will raise the NonLinearError exception, while solvers not supporting arithmetics will raise a ConvertExpressionError exception (see
    • Algebraic solutions (e.g., sqrt(2) are represented using the internal z3 object -- This is bound to change in the future.


  • Python 3.5: Full support for Python 3.5, all solvers are now tested (and working) on Python 3.5 (PR #287)
  • Improved installed solvers check (
    • --check now takes into account the bindings_dir and prints the version of the installed solver
    • Bindings are installed in different directories depending on the minor version of Python. In this way it is possible to use both Python 2.7 and 3.5.
    • There is a distinction btw installed solvers and solvers in the PYTHONPATH.
    • Qelim, Unsat-Core and Interpolants are also visualized (but not checked)
  • Support for reading compressed SMT-LIB files (.bz2)
  • Simplified HRPrinter code
  • Removed six dependency from type_checker (PR #283)
  • BddSimplifier (pysmt.simplifier.BddSimplifier): Uses BDDs to simplify the boolean structure of an SMT formula. (See (PR #286)



  • Bugfix in Z3Converter.walk_array_value. Thanks to Alberto Griggio for contributing this patch
  • Bugfix in DL Logic comparison (commit 9e9c8c)


Choose a tag to compare


  • MGSubstituter becomes the new default substitution method (PR #253)

    When performing substitution with a mapping like {a: b, Not(a), c}, Not(a) is considered before a. The previous
    behavior (MSSubstituter) would have substituted a first, and
    then the rule for Not(a) would not have been applied.

  • Removed argument user_options from Solver()


  • Added support for the Theory of Arrays.

    In addition to the SMT-LIB definition, we introduce the concept of
    Constant Array as supported by MathSAT and Z3. The theory is
    currently implemented for MathSAT, Z3, Boolector, CVC4.

    Thanks to Alberto Griggio, Satya Uppalapati and Ahmed
    for contributing through code and discussion to this


  • Simplifier: Enable simplification if IFF with constant:
    e.g., (a <-> False) into !a

  • Automatically enable Infix Notation by importing (PR #267)

  • SMT-LIB: support for define-sort commands without arguments

  • Improved default options for shortcuts:

    • Factory.is_* sets model generation and incrementality to False;
    • Factory.get_model() sets model generation to True, and
      incrementality to False.
    • Factory.Solver() sets model generation and incrementality to True;
  • Improved handling of options in Solvers (PR #250):

    Solver() takes **options as free keyword arguments. These options
    are checked by the class SolverOptions, in order to validate that
    these are meaningful options and perform a preliminary validation to
    catch typos etc. by raising a ValueError exception if the option is

    It is now possible to do: Solver(name="bdd", dynamic_reordering=True)


  • rePyCUDD: Upgrade to 75fe055 (PR #262)
  • CVC4: Upgrade to c15ff4 (PR #251)
  • CVC4: Enabled Quantified logic (PR #252)


  • Fixed bug in Non-linear theories comparison
  • Fixed bug in reset behavior of CVC4
  • Fixed bug in BTOR handling of bitwidth in shifts
  • Fixed bug in BTOR's get_value function
  • Fixed bug in BTOR, when operands did not have the same width after rewriting.


Choose a tag to compare


  • BitVectors: Added support for infix notation
  • Basic performance optimizations


  • Boolector: Upgraded to version 2.2.0


  • Fixed bug in ExactlyOne args unpacking. Thanks to Martin @hastyboomalert for reporting this.