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 * Simplification mode "incremental" no longer supported.
  17 * Support for array constants in constraints.
  18 * Syntax for array models has changed in some language front-ends.
  19 * New input/output languages supported: "smt2.0" and "smtlib2.0" to
  20   force SMT-LIB v2.0; "smt2.5" and "smtlib2.5" to force SMT-LIB v2.5;
  21   "smt2.6" and "smtlib2.6" to force SMT-LIB v2.6;
  22   "smt", "smtlib", "smt2", and "smtlib2" all refer to the current standard
  23   version 2.6.  If an :smt-lib-version is set in the input, that overrides
  24   the command line.
  25 * Abstract values in SMT-LIB models are now ascribed types (with "as").
  26 * In SMT-LIB model output, real-sorted but integer-valued constants are
  27   now printed in accordance with the standard (e.g. "1.0").
  28
  29 Changes since 1.3
  30 =================
  31
  32 * CVC4 now supports libc++ in addition to libstdc++ (this especially
  33   helps on Mac OS Mavericks).
  34 * The LFSC proof checker has been incorporated into CVC4 sources.
  35 * Theory of finite sets, handling the MLSS fragment (singleton, union,
  36   intersection, set subtraction, membership and subset).
  37 * By default, CVC4 builds in "production" mode (optimized, with fewer
  38   internal checks on).  The common alternative is a "debug" build, which
  39   is much slower.  By default, CVC4 builds with no GPL'ed dependences.
  40   However, this is not the best-performing version; for that, you should
  41   configure with "--enable-gpl --best", which links against GPL'ed
  42   libraries that improve usability and performance.  For details on
  43   licensing and dependences, see the README file.
  44 * Small API adjustments to Datatypes to even out the API and make it
  45   function better in Java.
  46 * Timed statistics are now properly updated even on process abort.
  47 * Better automatic handling of output language setting when using CVC4
  48   via API.  Previously, the "automatic" language setting was sometimes
  49   (though not always) defaulting to the internal "AST" language; it
  50   should now (correctly) default to the same as the input language
  51   (if the input language is supported as an output language), or the
  52   "CVC4" native output language if no input language setting is applied.
  53 * The SmtEngine cannot be safely copied with the copy constructor.
  54   Previous versions inadvertently permitted clients to do this via the
  55   API.  This has been corrected, copy and assignment of the SmtEngine
  56   is no longer permitted.
  57
  58 Changes since 1.2
  59 =================
  60
  61 New features:
  62 * SMT-LIB-compliant support for abs, to_real, to_int, is_int, which were
  63   previously missing
  64 * New bv2nat/int2bv operators for bitvector/integer inter-compatibility.
  65 * Support in linear logics for /, div, and mod by constants (with the
  66   --rewrite-divk command line option).
  67 * Parsing support for TPTP's TFF and TFA formats.
  68 * A new theory of strings: word (dis-)equations, length constraints,
  69   regular expressions.
  70 * Increased compliance to SMT-LIBv2, numerous bugs and usability issues
  71   resolved.
  72 * New :command-verbosity SMT option to silence success and error messages
  73   on a per-command basis, and API changes to Command infrastructure to
  74   support this.
  75
  76 Behavioral changes:
  77 * It is no longer permitted to request model or proof generation if there's
  78   been an intervening push/pop.
  79 * User-defined symbols (define-funs) are no longer reported in the output
  80   of get-model commands.
  81 * Exit codes are now more standard for UNIX command-line tools.  Exit code
  82   zero means no error---but the result could be sat, unsat, or unknown---and
  83   nonzero means error.
  84
  85 API changes:
  86 * Expr::substitute() now capable of substituting operators (e.g.,
  87   function symbols under an APPLY_UF)
  88 * Numerous improvements to the Java language bindings
  89
  90 Changes since 1.1
  91 =================
  92
  93 * Real arithmetic now has three simplex solvers for exact precision linear
  94   arithmetic: the classical dual solver and two new solvers based on
  95   techniques for minimizing the sum of infeasibilities. GLPK can now be used
  96   as a heuristic backup to the exact precision solvers.  GLPK must be enabled
  97   at configure time. See --help for more information on enabling these solvers.
  98 * added support for "bit0" and "bit1" bitvector constants in SMT-LIB v1.2
  99 * support for theory "alternates": new ability to prototype new decision
 100   procedures that are selectable at runtime
 101 * various bugfixes
 102
 103 Changes since 1.0
 104 =================
 105
 106 * bit-vector solver now has a specialized decision procedure for unsigned bit-
 107   vector inequalities
 108 * numerous important bug fixes, performance improvements, and usability
 109   improvements
 110 * support for multiline input in interactive mode
 111 * Win32-building support via mingw
 112 * SMT-LIB get-model output now is easier to machine-parse: contains (model...)
 113 * user patterns for quantifier instantiation are now supported in the
 114   SMT-LIBv1.2 parser
 115 * --finite-model-find was incomplete when using --incremental, now fixed
 116 * the E-matching procedure is slightly improved
 117 * Boolean terms are now supported in datatypes
 118 * tuple and record support have been added to the compatibility library
 119 * driver verbosity change: for printing all commands as they're executed, you
 120   now need verbosity level >= 3 (e.g., -vvv) instead of level 1 (-v).  This
 121   allows tracing the solver's activities (with -v and -vv) without having too
 122   much output.
 123 * to make CVC4 quieter in abnormal (e.g., "warning" conditions), you can
 124   use -q.  Previously, this would silence all output (including "sat" or
 125   "unsat") as well.  Now, single -q silences messages and warnings, and
 126   double -qq silences all output (except on exception or signal).
 127
 128 -- Morgan Deters <mdeters@cs.nyu.edu>  Wed, 02 Jul 2014 14:45:05 -0400