pySMT 0.6.0 is out! This is a quite big release with a few backwards incompatible changes. The most important ones concern a revised handling of constants (including support for GMPY2), and a refactoring of the TreeWalker to avoid recursion. Find below the full changelog for more information.
You can upgrade via pip ( pip install --upgrade pysmt ) or by downloading the latest version from github ( https://github.com/pysmt/pysmt )
Let us know what you think!
BACKWARDS INCOMPATIBLE CHANGES:
Integer, Fraction and Numerals are now defined in pysmt.constants
(see below for details). The breaking changes are:
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 !
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:
pratt.py and parser.py. These files were removed and the parser
combined into a unique parsing.py 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
Removed deprecated methods (PR #332):
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
Conversion can be achieved via:
install.py (pysmt-install) and shell.py 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.
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
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
of options that are solver dependent. It is thus possible to
directly pass options to the underlying solver.
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
Fixed: SMT-LIB define-fun serialization (PR #315)