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791 days ago

Changelog History
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  • v8.14 Changes

    March 29, 2021
    • Improve the fast all-sat algorithm to also support uninterpreted values.

    • Generalize svTestBit to work on floats, returning the respecting bit in the representation of the float.

    • Fixes to crack-num facility of how we display floats in detail.

  • v8.13 Changes

    March 21, 2021
    • Generalized floating point: Add support for brain-floats, with type SFPBFloat, which has 8-bits of exponent and 8-bits of significand. This format is affectionately called "brain-float" because it's often used in modeling neural networks machine-learning applications, offering a wider-range than IEEE's half-float, at the exponse of reduced precision. It has 8-exponent bits and 8-significand bits, including the hidden bit.

    • Add support for SRational type, rational values built out of the ratio of two integers. Use the module "Data.SBV.Rational", which exports the constructor .% to build rationals. Note that you cannot take numerator and denominator of rationals apart, since SMTLib has no way of storing the rational in a canonical way. Otherwise, symbolic rationals follow the same rules as Haskell's Rational type.

    • SBV now implements a faster allSat algorithm, which applies in most common use cases. (Essentially, when there are no uninterpreted values or sorts present.) The new algorithm has been measured to be at least an order of magnitude faster or more in common cases as it splits the search space into disjoint models, reducing the burden of accummulated lemmas over multiple calls. (See for details.)

  • v8.12 Changes

    March 09, 2021
    • Fix a bug in crackNum for unsigned-integer values, which incorrectly showed a negation sign for values with msb set to 1.
  • v8.11 Changes

    March 09, 2021
    • SBV now supports floating-point numbers with arbitrary exponent and significand sizes. The type is SFloatingPoint eb sb, where eb and sb are type-level naturals. In particular, SBV can now reason about half-floats, which are used much more frequently in ML applications. Through the LibBF binding, you can also use these concretely, so if you have a use case for computing with floats, you can use SBV as a vehicle for doing so. The exponent/significand sizes are limited to those supported by the LibBF bindings, though the allowed range is rather large and should not be a limitation in practice. (In particular, you'll most likely run out of memory before you hit precision limits!)

    • We now support a separate crackNum parameter in model display. If set to True (default is False), SBV will display numeric values of bounded integers, words, and all floats (SDouble, SFloat, and the new SFloatingPoint) in models in detail, showing how they are laid out in memory. Numbers follow the usual 2's-complement notation if they are signed, bit-vectors if they are not signed, and the floats follow the usual IEEE754 binary layout rules. Similarly, there's now a function crack :: SBV a -> String that does the same for non-model printing contexts.

    • Changed the isNonModelVar config param to take a String (instead of Text). Simplifies programming.

    • Changes to make SBV compile with GHC9.0. Thanks to Ryan Scott for the patch.

  • v8.10 Changes

    February 13, 2021
    • Add "Documentation/SBV/Examples/Misc/NestedArray.hs" to demonstrate how to model multi-dimensional arrays in SBV.

    • Add "Documentation/SBV/Examples/Puzzles/Murder.hs" as another puzzle example.

    • Performance updates: Thanks to Jeff Young, SBV now uses better underlying data structures, performing better for heavy use-case scenarios.

    • SBV now tracks constants more closely in query mode, providing more support for constant arrays in a seamless way. (See #574 for details.)

    • Pop-calls are now support for Yices and Boolector. (#577)

    • Changes required to make SBV work with latest version of z3 regarding String and Characters, which now allow for unicode characters. This required renaming of certain recognizers in 'Data.SBV.Char' to restrict them to the Latin1 subset. Otherwise, the changes should be transparent to the end user. Please report any issues you might run into when you use SChar and SString types.

  • v8.9 Changes

    October 28, 2020
    • Rename 'sbvAvailableSolvers' to 'getAvailableSolvers'.

    • Use SMTLib's int2bv if supported by the backend solver. If not, we still do a manual translation. (CVC4 and z3 support it natively, Yices and MathSAT does not, for which we do the manual translation. ABC and dReal doesn't support the coversion at all, since former doesn't support integers and the latter doesn't support bit-vectors.) Thanks to Martin Lundfall for the initial pull request.

    • Add sym as a synonym for uninterpret. This allows us to write expressions of the form sat $ sym "a" - sym "b" .== (0::SInteger), without resorting to lambda expressions or having to explicitly be in the Symbolic monad.

    • Added missing instances for overflow-checking arithmetic of arbitrary sized signed and unsigned bitvectors.

    • In a sat (or allSat) call, also return the values of the uninterpreted values, along with all the explicitly named inputs. Strictly speaking, this is backwards-incompatible, but it the new behavior is consistent with how we handle uninterpreted values in general.

    • Improve SMTLib logic-detection code to use generics.

  • v8.8 Changes

    September 04, 2020
    • Reworked uninterpreted sorts. Added new function mkUninterpretedSort to make declaration of completely uninterpreted sorts easier. In particular, we now automatically introduce the symbolic variant of the type (by prefixing the underlying type with S) so it becomes automatically available, both for uninterpreted sorts and enumerations. In the latter case, we also automatically introduce the value sX for each enumeration constant X, defined to be precisely literal X.

    • Handle incremental mode table-declarations that depend on freshly declared variables. Thanks to Gergő Érdi for reporting.

    • Fix a soundness bug in SFunArray caching. Thanks to Gergő Érdi for reporting. See for details.

    • Add support for the dReal solver, and introduce the notion of delta-satisfiability, where you can now check properties to be satisfiable against delta-perturbations. See "Documentation.SBV.Examples.DeltaSat.DeltaSat" for a basic example.

    • Add "extraArgs" parameter to SMTConfig to simplify passing extra command line arguments to the solver.

    • Add a method

      sListArray :: (HasKind a, SymVal b) => b -> [(SBV a, SBV b)] -> array a b

      to the SymArray class, which allows for creation of arrays from lists of constant or symbolic lists of pairs. The first argument is the value to use for uninitialized entries. Note that the initializer must be a known constant, i.e., it cannot be symbolic. Latter elements of the list will overwrite the earlier ones, if there are repeated keys.

    • Thanks to Jan Hrcek, a whole bunch of typos were fixed in the documentation and the source code. Much appreciated!

  • v8.7 Changes

    June 30, 2020
    • Add support for concurrent versions of solvers for query problems. Similar to satWithAny, proveWithAny etc., except when we have queries. Thanks to Jeffrey Young for the idea and the implementation.

    • Add "Documentation.SBV.Examples.Misc.Newtypes", demonstrating how to use newtypes over existing symbolic types as symbolic quantities themselves. Thanks to Curran McConnell for the example.

    • Added new predicate sNotElem, negating sElem.

    • Added new predicate distinctExcept. This is same as distinct except you can also provide an ignore list. The elements in the first list will be checked to be distinct from each other, or belong to the second list. This is good for writing constraints that either require a default value or if picked be different from each other for a set of variables. This sort of constraint can be coded in user space, but SBV generates efficient code instead of the obvious quadratic number of constraints.

    • Add function 'algRealToRational' that can convert an algebraic-real to a Haskell rational. We get an either value: If the algebraic real is exact, then it returns a 'Left' value that represents the value precisely. Otherwise, it returns a 'Right' value, which is only an approximation. Note: Setting 'printRealPrec' in SMTConfig to a higher value will increase the precision at the cost of more computation by the SMT solver.

    • Removed the 'SMTValue' class. It's functionality was not really needed. If you ever used this class, removing it from your type signatures should fix the issue. (You might have to add SymVal constraint if you did not already have it.) Please get in touch if you used this class in some cunning way and you need its functionality back.

    • Reworked SBVBenchSuite api, Phase 1 of BenchSuite completed.

    • Add support for addAxiom command to work in the interactive mode. Thanks to Martin Lundfall for the feedback.

    • Fixed proveWithAny and satWithAny functions so they properly kill the solvers that did not terminate first. Previously, they became zombies if they didn't end up quickly. Thanks to Robert Dockins for the investigation and the fix.

    • Fixed a bug where resetAssertions call was forgetting to restore the array and table contexts. Thanks to Martin Lundfall for reporting.

  • v8.6 Changes

    February 08, 2020
    • Fix typo in error message. Thanks to Oliver Charles for the patch.

    • Fix parsing of sequence counter-examples to accommodate recent changes in z3.

    • Add missing exports related to N-bit words. Thanks to Markus Barenhoff for the patch.

    • Generalized code-generation functions to accept a function with an arbitrary return type, which was previously just unit. This allows for complicated code-generation scenarios where one code-gen run can produce input to the next.

    • Scalability improvements for internal data structures. Thanks to Brian Huffman for the patch.

    • Add interpolation support for Z3, following changes to that solver. Note that SBV now supports two different APIs for interpolation extraction, one for Z3 and the other for MathSAT. This is unfortunate, but necessary since interpolant extraction isn't quite standardized amongst solvers and MathSAT and Z3 use sufficiently different calling mechanisms to warrant their own calls. See 'Documentation.SBV.Examples.Queries.Interpolants' for examples that illustrate both cases.

    • Add a new argument to displayModels function to allow rearranging of the results in an 'allSatcall. Strictly speaking this is a backwards breaking change, but substitutingid` for the new argument gives you old functionality, so easy to work-around.

  • v8.5 Changes

    October 16, 2019
    • Changes to compile with GHC 8.8. Thanks to Oliver Charles for the patch.

    • Minor fix to how kinds are shown for non-standard sizes.

    • Thanks to Jeffrey Young, SBV now has a performance benchmark test-suite. The framework still new, but should help in the long run to make sure SBV performance doesn't regress on its test-suite, and by extension in general usage.