NEWS

   1 This file contains a summary of important user-visible changes.
   2
   3 Changes since 1.4
   4 =================
   5
   6 * Improved heuristics for reasoning about non-linear arithmetic.
   7 * Native support for syntax-guided synthesis (sygus).
   8 * Support for many new heuristics for reasoning with quantifiers, including
   9   finite model finding.
  10 * Support for proofs for uninterpreted functions, arrays, bitvectors, and
  11   their combinations.
  12 * Performance improvements to existing theories.
  13 * A new theory of sets with cardinality and relations.
  14 * A new theory of strings.
  15 * Support for unsat cores.
  16 * Support for separation logic constraints.
  17 * Simplification mode "incremental" no longer supported.
  18 * Support for array constants in constraints.
  19 * Syntax for array models has changed in some language front-ends.
  20 * New input/output languages supported: "smt2.0" and "smtlib2.0" to
  21   force SMT-LIB v2.0; "smt2.5" and "smtlib2.5" to force SMT-LIB v2.5;
  22   "smt2.6" and "smtlib2.6" to force SMT-LIB v2.6;
  23   "smt", "smtlib", "smt2", and "smtlib2" all refer to the current standard
  24   version 2.6.  If an :smt-lib-version is set in the input, that overrides
  25   the command line.
  26 * Abstract values in SMT-LIB models are now ascribed types (with "as").
  27 * In SMT-LIB model output, real-sorted but integer-valued constants are
  28   now printed in accordance with the standard (e.g. "1.0").
  29
  30 Changes since 1.3
  31 =================
  32
  33 * CVC4 now supports libc++ in addition to libstdc++ (this especially
  34   helps on Mac OS Mavericks).
  35 * The LFSC proof checker has been incorporated into CVC4 sources.
  36 * Theory of finite sets, handling the MLSS fragment (singleton, union,
  37   intersection, set subtraction, membership and subset).
  38 * By default, CVC4 builds in "production" mode (optimized, with fewer
  39   internal checks on).  The common alternative is a "debug" build, which
  40   is much slower.  By default, CVC4 builds with no GPL'ed dependences.
  41   However, this is not the best-performing version; for that, you should
  42   configure with "--enable-gpl --best", which links against GPL'ed
  43   libraries that improve usability and performance.  For details on
  44   licensing and dependences, see the README file.
  45 * Small API adjustments to Datatypes to even out the API and make it
  46   function better in Java.
  47 * Timed statistics are now properly updated even on process abort.
  48 * Better automatic handling of output language setting when using CVC4
  49   via API.  Previously, the "automatic" language setting was sometimes
  50   (though not always) defaulting to the internal "AST" language; it
  51   should now (correctly) default to the same as the input language
  52   (if the input language is supported as an output language), or the
  53   "CVC4" native output language if no input language setting is applied.
  54 * The SmtEngine cannot be safely copied with the copy constructor.
  55   Previous versions inadvertently permitted clients to do this via the
  56   API.  This has been corrected, copy and assignment of the SmtEngine
  57   is no longer permitted.
  58
  59 Changes since 1.2
  60 =================
  61
  62 New features:
  63 * SMT-LIB-compliant support for abs, to_real, to_int, is_int, which were
  64   previously missing
  65 * New bv2nat/int2bv operators for bitvector/integer inter-compatibility.
  66 * Support in linear logics for /, div, and mod by constants (with the
  67   --rewrite-divk command line option).
  68 * Parsing support for TPTP's TFF and TFA formats.
  69 * A new theory of strings: word (dis-)equations, length constraints,
  70   regular expressions.
  71 * Increased compliance to SMT-LIBv2, numerous bugs and usability issues
  72   resolved.
  73 * New :command-verbosity SMT option to silence success and error messages
  74   on a per-command basis, and API changes to Command infrastructure to
  75   support this.
  76
  77 Behavioral changes:
  78 * It is no longer permitted to request model or proof generation if there's
  79   been an intervening push/pop.
  80 * User-defined symbols (define-funs) are no longer reported in the output
  81   of get-model commands.
  82 * Exit codes are now more standard for UNIX command-line tools.  Exit code
  83   zero means no error---but the result could be sat, unsat, or unknown---and
  84   nonzero means error.
  85
  86 API changes:
  87 * Expr::substitute() now capable of substituting operators (e.g.,
  88   function symbols under an APPLY_UF)
  89 * Numerous improvements to the Java language bindings
  90
  91 Changes since 1.1
  92 =================
  93
  94 * Real arithmetic now has three simplex solvers for exact precision linear
  95   arithmetic: the classical dual solver and two new solvers based on
  96   techniques for minimizing the sum of infeasibilities. GLPK can now be used
  97   as a heuristic backup to the exact precision solvers.  GLPK must be enabled
  98   at configure time. See --help for more information on enabling these solvers.
  99 * added support for "bit0" and "bit1" bitvector constants in SMT-LIB v1.2
 100 * support for theory "alternates": new ability to prototype new decision
 101   procedures that are selectable at runtime
 102 * various bugfixes
 103
 104 Changes since 1.0
 105 =================
 106
 107 * bit-vector solver now has a specialized decision procedure for unsigned bit-
 108   vector inequalities
 109 * numerous important bug fixes, performance improvements, and usability
 110   improvements
 111 * support for multiline input in interactive mode
 112 * Win32-building support via mingw
 113 * SMT-LIB get-model output now is easier to machine-parse: contains (model...)
 114 * user patterns for quantifier instantiation are now supported in the
 115   SMT-LIBv1.2 parser
 116 * --finite-model-find was incomplete when using --incremental, now fixed
 117 * the E-matching procedure is slightly improved
 118 * Boolean terms are now supported in datatypes
 119 * tuple and record support have been added to the compatibility library
 120 * driver verbosity change: for printing all commands as they're executed, you
 121   now need verbosity level >= 3 (e.g., -vvv) instead of level 1 (-v).  This
 122   allows tracing the solver's activities (with -v and -vv) without having too
 123   much output.
 124 * to make CVC4 quieter in abnormal (e.g., "warning" conditions), you can
 125   use -q.  Previously, this would silence all output (including "sat" or
 126   "unsat") as well.  Now, single -q silences messages and warnings, and
 127   double -qq silences all output (except on exception or signal).
 128