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Do not use existential variables for integer division #881
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This patch implements integer remainder in terms of integer division rather than the opposite. This avoids the introduction of fresh existential variables. Fixes OCamlPro#875
The reasoning for this one is mostly explained in #875. Currently, we rewrite To avoid causing the creation of fresh constants, the PR flips things around: now, we rewrite |
src/lib/reasoners/arith.ml
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let r, ctx' = X.make E.Ints.(t1 / ~$$a2) in | ||
P.mult_const Q.m_one (embed r), ctx' @ ctx | ||
else | ||
(* 0 <= t1 % t2 = t1 - t2 * (t1 / t2) < |t2| *) |
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(* 0 <= t1 % t2 = t1 - t2 * (t1 / t2) < |t2| *) | |
(* 0 <= t1 % t2 = t1 - |t2| * (t1 / t2) < |t2| *) |
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I think I prefer the version that is always true, even if in this case t2
is positive so t2 = |t2|
, I will clarify.
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I have no strong opinion about it. For me it was clearer that the formula agrees syntactically with the code below.
src/lib/reasoners/arith.ml
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(* Compute [t1 % t2] as [t1 - |t2| * (t1 / |t2|)]. | ||
|
||
Requires: [t1], [t2] have type [Tint] | ||
Requires: [p1] is the representative for [t1] | ||
Requires: [p2] is the representative for [t2] | ||
Requires: [p2] is a non-zero constant *) |
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The previous comment gave a precise definition of the modulo used by Arith
.
(* t1 % t2 = md <->
c1. 0 <= md ;
c2. md < t2 ;
c3. exists k. t1 = t2 * k + t ;
c4. t2 <> 0 (already checked) *)
It's meaningful to know that we choose an integer between 0
and t2
as the representative element of the equivalence classes of Z/t2Z
.
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t1 % t2
here is not an equivalence class, it is defined as the remainder of euclidean division, which is an integer between 0
and |t2|
by definition (note that the condition c2
in the pre-existing comment was incorrect because t2
can be negative). Should be clear with the added definition of %
as remainder of Euclidean division.
src/lib/reasoners/arith.ml
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P.mult_const (Q.div Q.one coef_p2) (embed r) in | ||
P.sub p rp, ctx' @ ctx | ||
| _ -> assert false | ||
(* Compute [t1 % t2] as [t1 - |t2| * (t1 / |t2|)]. |
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I know the division symbol /
here means the integer division but at the first sight, it was a bit confusing as the fact t1
and t2
are integer is mentioned later. We may precise that /
is the integer division?
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Sure, added a note that /
is Euclidean division here, and that %
is the remainder of Euclidean division. Also renamed the function mk_euc_modulo
.
src/lib/reasoners/arith.ml
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let a2 = Q.to_z n2 |> Z.abs in | ||
assert (Z.sign a2 > 0); | ||
|
||
(* NB: [t1 % t2] = [t1 % |t2|] *) |
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Here the equality =
denotes the usual equality relation between integers and this equation is consequence of our choice of representative term for the equivalence classes. I think we should clarify this point.
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This follows from the definition of t1 % t2
as the remainder of euclidean division. Anyways, I have removed this to avoid recomputing X.make t1
and call mk_euc_division
directly instead.
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This follows from the definition of
t1 % t2
as the remainder of euclidean division.
It's exactly what I said ;)
src/lib/reasoners/arith.ml
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if Q.sign n2 < 0 then | ||
(* t1 / (-|t2|) = -(t1 / |t2|)*) | ||
let r, ctx' = X.make E.Ints.(t1 / ~$$a2) in | ||
P.mult_const Q.m_one (embed r), ctx' @ ctx |
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If I understand well, we don't need to produce here an interval for the case n2 < 0
as the recursive call X.make
will produce the appropriate interval for -n2
?
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Yeah, here we just rewrite t1 / (-|t2|)
into -(t1 / |t2|)
and then we let the recursive call take care of things. Although I am now realizing this means we will compute X.make t1
twice; I will inline the code.
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Actually I have removed the distinction; we will create t1 / n
and t1 / (-n)
and rely on reasoning to prove they are identical, it is less error-prone.
It turns out that OCamlPro#881 revealed a latent issue with the implementation in OCamlPro#733 When we encounter a [bv2nat] term, we create a *term* that represents the [bv2nat] computation, then call [X.make] on the result. This has the unfortunate effect that the sub-terms of that new term are not added to the Union-Find (or at least not before the term itself). This is bad, but was harmless at the time. However, the resulting term from a call of [bv2nat] includes divisions. And since OCamlPro#881 divisions are represented by an uninterpreted term rather than an existential variable — and [IntervalCalculus.add] inspects that term, rightfully expecting that its sub-terms have been added to the Union-Find, which in this case they are not, and so we crash. This patch fixes the issue by introducing an uninterpreted term for the result of [bv2nat] and adding the equality between that uninterpreted term and the [bv2nat] computation. This equality is then processed as a term on its own, ensuring that subterms are added to the Union-Find before the terms that contain them. Note that long-term, we probably want to get rid of the construction of [bv2nat] terms directly in [X.make] in favor of propagators in a follow-up to OCamlPro#944 . This would avoid needing to go through terms for this.
It turns out that OCamlPro#881 revealed a latent issue with the implementation in OCamlPro#733 When we encounter a [bv2nat] term, we create a *term* that represents the [bv2nat] computation, then call [X.make] on the result. This has the unfortunate effect that the sub-terms of that new term are not added to the Union-Find (or at least not before the term itself). This is bad, but was harmless at the time. However, the resulting term from a call of [bv2nat] includes divisions. And since OCamlPro#881 divisions are represented by an uninterpreted term rather than an existential variable — and [IntervalCalculus.add] inspects that term, rightfully expecting that its sub-terms have been added to the Union-Find, which in this case they are not, and so we crash. This patch fixes the issue by introducing an uninterpreted term for the result of [bv2nat] and adding the equality between that uninterpreted term and the [bv2nat] computation. This equality is then processed as a term on its own, ensuring that subterms are added to the Union-Find before the terms that contain them. Note that long-term, we probably want to get rid of the construction of [bv2nat] terms directly in [X.make] in favor of propagators in a follow-up to OCamlPro#944 . This would avoid needing to go through terms for this.
It turns out that #881 revealed a latent issue with the implementation in #733 When we encounter a [bv2nat] term, we create a *term* that represents the [bv2nat] computation, then call [X.make] on the result. This has the unfortunate effect that the sub-terms of that new term are not added to the Union-Find (or at least not before the term itself). This is bad, but was harmless at the time. However, the resulting term from a call of [bv2nat] includes divisions. And since #881 divisions are represented by an uninterpreted term rather than an existential variable — and [IntervalCalculus.add] inspects that term, rightfully expecting that its sub-terms have been added to the Union-Find, which in this case they are not, and so we crash. This patch fixes the issue by introducing an uninterpreted term for the result of [bv2nat] and adding the equality between that uninterpreted term and the [bv2nat] computation. This equality is then processed as a term on its own, ensuring that subterms are added to the Union-Find before the terms that contain them. Note that long-term, we probably want to get rid of the construction of [bv2nat] terms directly in [X.make] in favor of propagators in a follow-up to #944 . This would avoid needing to go through terms for this.
CHANGES: ### Command-line interface - Enable FPA theory by default (OCamlPro/alt-ergo#1177) - Remove deprecated output channels (OCamlPro/alt-ergo#782) - Deprecate the --use-underscore since it produces models that are not SMT-LIB compliant (OCamlPro/alt-ergo#805) - Add --dump-models-on to dump models on a specific output channel (OCamlPro/alt-ergo#838) - Use consistent return codes (OCamlPro/alt-ergo#842) - Add --continue-on-error flag to set the SMT-LIB error behavior (OCamlPro/alt-ergo#853) - Make dolmen the default value for the --frontend option (OCamlPro/alt-ergo#857) - Restore functionality to broken `--profiling` option (OCamlPro/alt-ergo#947) - Add bare-bones support for interactive input in SMT-LIB format (OCamlPro/alt-ergo#949) - Less confusing behavior on timeout (OCamlPro/alt-ergo#982, OCamlPro/alt-ergo#984) - Add `--strict` option for SMT-LIB compliant mode (OCamlPro/alt-ergo#916, OCamlPro/alt-ergo#1133) - Deprecate `sum`, `typing` and `warnings` debug flags (OCamlPro/alt-ergo#1204) ### SMT-LIB support - Add support for the many new SMT-LIB commands (OCamlPro/alt-ergo#837, OCamlPro/alt-ergo#848, OCamlPro/alt-ergo#852, OCamlPro/alt-ergo#863, OCamlPro/alt-ergo#911, OCamlPro/alt-ergo#942, OCamlPro/alt-ergo#945, OCamlPro/alt-ergo#961, OCamlPro/alt-ergo#975, OCamlPro/alt-ergo#1069) - Expose the FPA rounding builtin in the SMT-LIB format (OCamlPro/alt-ergo#876, OCamlPro/alt-ergo#1135) - Allow changing the SAT solver using (set-option) (OCamlPro/alt-ergo#880) - Add support for the `:named` attribute (OCamlPro/alt-ergo#957) - Add support for quoted identifiers (OCamlPro/alt-ergo#909, OCamlPro/alt-ergo#972) - Add support for naming lemmas in SMT-LIB syntax (OCamlPro/alt-ergo#1141, OCamlPro/alt-ergo#1143) ### Model generation - Use post-solve SAT environment in model generation, fixing issues where incorrect models were generated (OCamlPro/alt-ergo#789) - Restore support for records in models (OCamlPro/alt-ergo#793) - Use abstract values instead of dummy values in models where the actual value does not matter (OCamlPro/alt-ergo#804, OCamlPro/alt-ergo#835) - Use fresh names for all abstract values to prevent accidental captures (OCamlPro/alt-ergo#811) - Add support for model generation with the default CDCL solver (OCamlPro/alt-ergo#829) - Support model generation for the BV theory (OCamlPro/alt-ergo#841, OCamlPro/alt-ergo#968) - Add support for optimization (MaxSMT / OptiSMT) with lexicographic Int and Real objectives (OCamlPro/alt-ergo#861, OCamlPro/alt-ergo#921) - Add a SMT-LIB printer for expressions (OCamlPro/alt-ergo#952, OCamlPro/alt-ergo#981, OCamlPro/alt-ergo#1082, OCamlPro/alt-ergo#931, OCamlPro/alt-ergo#932) - Ensure models have a value for all constants in the problem (OCamlPro/alt-ergo#1019) - Fix a rare soundness issue with integer constraints when model generation is enabled (OCamlPro/alt-ergo#1025) - Support model generation for the ADT theory (OCamlPro/alt-ergo#1093, OCamlPro/alt-ergo#1153) ### Theory reasoning - Add word-level propagators for the BV theory (OCamlPro/alt-ergo#944, OCamlPro/alt-ergo#1004, OCamlPro/alt-ergo#1007, OCamlPro/alt-ergo#1010, OCamlPro/alt-ergo#1011, OCamlPro/alt-ergo#1012, OCamlPro/alt-ergo#1040, OCamlPro/alt-ergo#1044, OCamlPro/alt-ergo#1054, OCamlPro/alt-ergo#1055, OCamlPro/alt-ergo#1056, OCamlPro/alt-ergo#1057, OCamlPro/alt-ergo#1065, OCamlPro/alt-ergo#1073, OCamlPro/alt-ergo#1144, OCamlPro/alt-ergo#1152) - Add interval domains and arithmetic propagators for the BV theory (OCamlPro/alt-ergo#1058, OCamlPro/alt-ergo#1083, OCamlPro/alt-ergo#1084, OCamlPro/alt-ergo#1085) - Native support for bv2nat of bit-vector normal forms (OCamlPro/alt-ergo#1154) - Fix incompleteness issues in the BV solver (OCamlPro/alt-ergo#978, OCamlPro/alt-ergo#979) - Abstract more arguments of AC symbols to avoid infinite loops when they contain other AC symbols (OCamlPro/alt-ergo#990) - Do not make irrelevant decisions in CDCL solver, improving performance slightly (OCamlPro/alt-ergo#1041) - Rewrite the ADT theory to use domains and integrate the enum theory into the ADT theory (OCamlPro/alt-ergo#1078, OCamlPro/alt-ergo#1086, OCamlPro/alt-ergo#1087, OCamlPro/alt-ergo#1091, OCamlPro/alt-ergo#1094, OCamlPro/alt-ergo#1138) - Rewrite the Intervals module entirely (OCamlPro/alt-ergo#1108) - Add maximize/minimize terms for matching (OCamlPro/alt-ergo#1166) - Internalize `sign_extend` and `repeat` (OCamlPro/alt-ergo#1192) - Run cross-propagators to completion (OCamlPro/alt-ergo#1221) - Support binary distinct on arbitrary bit-widths (OCamlPro/alt-ergo#1222) - Only perform optimization when building a model (OCamlPro/alt-ergo#1224) - Make sure domains do not overflow the default domain (OCamlPro/alt-ergo#1225) - Do not build unnormalized values in `zero_extend` (OCamlPro/alt-ergo#1226) ### Internal/library changes - Rewrite the Vec module (OCamlPro/alt-ergo#607) - Move printer definitions closer to type definitions (OCamlPro/alt-ergo#808) - Mark proxy names as reserved (OCamlPro/alt-ergo#836) - Use a Zarith-based representation for numbers and bit-vectors (OCamlPro/alt-ergo#850, OCamlPro/alt-ergo#943) - Add native support for (bvnot) in the BV solver (OCamlPro/alt-ergo#856) - Add constant propagators for partially interpreted functions (OCamlPro/alt-ergo#869) - Remove `Util.failwith` in favor of `Fmt.failwith` (OCamlPro/alt-ergo#872) - Add more `Expr` smart constructors (OCamlPro/alt-ergo#877, OCamlPro/alt-ergo#878) - Do not use existential variables for integer division (OCamlPro/alt-ergo#881) - Preserve `Subst` literals to prevent accidental incompleteness (OCamlPro/alt-ergo#886) - Properly start timers (OCamlPro/alt-ergo#924) - Compute a concrete representation of a model instead of performing (OCamlPro/alt-ergo#925) - Allow direct access to the SAT API in the Alt-Ergo library computations during printing (OCamlPro/alt-ergo#927) - Better handling for step limit (OCamlPro/alt-ergo#936) - Add a generic option manager to deal with the dolmen state (OCamlPro/alt-ergo#951) - Expose an imperative SAT API in the Alt-Ergo library (OCamlPro/alt-ergo#962) - Keep track of the SMT-LIB mode (OCamlPro/alt-ergo#971) - Add ability to decide on semantic literals (OCamlPro/alt-ergo#1027, OCamlPro/alt-ergo#1118) - Preserve trigger order when parsing quantifiers with multiple trigger (OCamlPro/alt-ergo#1046). - Store domains inside the union-find module (OCamlPro/alt-ergo#1119) - Remove some polymorphic hashtables (OCamlPro/alt-ergo#1219) ### Build and integration - Drop support for OCaml <4.08.1 (OCamlPro/alt-ergo#803) - Use dune-site for the inequalities plugins. External pluginsm ust now be registered through the dune-site plugin mechanism in the `(alt-ergo plugins)` site to be picked up by Alt-Ergo (OCamlPro/alt-ergo#1049). - Add a release workflow (OCamlPro/alt-ergo#827) - Add a Windows workflow (OCamlPro/alt-ergo#1203) - Mark the dune.inc file as linguist-generated to avoid huge diffs (OCamlPro/alt-ergo#830) - Use GitHub Actions badges in the README (OCamlPro/alt-ergo#882) - Use `dune build @check` to build the project (OCamlPro/alt-ergo#887) - Enable warnings as errors on the CI (OCamlPro/alt-ergo#888) - Uniformization of internal identifiers generation (OCamlPro/alt-ergo#905, OCamlPro/alt-ergo#918) - Use an efficient `String.starts_with` implementation (OCamlPro/alt-ergo#912) - Fix the Makefile (OCamlPro/alt-ergo#914) - Add `Logs` dependency (OCamlPro/alt-ergo#1206) - Use `dynamic_include` to include the generated file `dune.inc` (OCamlPro/alt-ergo#1199) - Support Windows (OCamlPro/alt-ergo#1184,OCamlPro/alt-ergo#1189,OCamlPro/alt-ergo#1195,OCamlPro/alt-ergo#1199,OCamlPro/alt-ergo#1200) - Wrap the library `Alt_ergo_prelude` (OCamlPro/alt-ergo#1223) ### Testing - Use --enable-assertions in tests (OCamlPro/alt-ergo#809) - Add a test for push/pop (OCamlPro/alt-ergo#843) - Use the CDCL solver when testing model generation (OCamlPro/alt-ergo#938) - Do not test .smt2 files with the legacy frontend (OCamlPro/alt-ergo#939) - Restore automatic creation of .expected files (OCamlPro/alt-ergo#941) ### Documentation - Add a new example for model generation (OCamlPro/alt-ergo#826) - Add a Pygments lexer for the Alt-Ergo native language (OCamlPro/alt-ergo#862) - Update the current authors (OCamlPro/alt-ergo#865) - Documentation of the `Enum` theory (OCamlPro/alt-ergo#871) - Document `Th_util.lit_origin` (OCamlPro/alt-ergo#915) - Document the CDCL-Tableaux solver (OCamlPro/alt-ergo#995) - Document Windows support (OCamlPro/alt-ergo#1216) - Remove instructions to install Alt-Ergo on Debian (OCamlPro/alt-ergo#1217) - Document optimization feature (OCamlPro/alt-ergo#1231)
CHANGES: ### Command-line interface - Enable FPA theory by default (OCamlPro/alt-ergo#1177) - Remove deprecated output channels (OCamlPro/alt-ergo#782) - Deprecate the --use-underscore since it produces models that are not SMT-LIB compliant (OCamlPro/alt-ergo#805) - Add --dump-models-on to dump models on a specific output channel (OCamlPro/alt-ergo#838) - Use consistent return codes (OCamlPro/alt-ergo#842) - Add --continue-on-error flag to set the SMT-LIB error behavior (OCamlPro/alt-ergo#853) - Make dolmen the default value for the --frontend option (OCamlPro/alt-ergo#857) - Restore functionality to broken `--profiling` option (OCamlPro/alt-ergo#947) - Add bare-bones support for interactive input in SMT-LIB format (OCamlPro/alt-ergo#949) - Less confusing behavior on timeout (OCamlPro/alt-ergo#982, OCamlPro/alt-ergo#984) - Add `--strict` option for SMT-LIB compliant mode (OCamlPro/alt-ergo#916, OCamlPro/alt-ergo#1133) - Deprecate `sum`, `typing` and `warnings` debug flags (OCamlPro/alt-ergo#1204) ### SMT-LIB support - Add support for the many new SMT-LIB commands (OCamlPro/alt-ergo#837, OCamlPro/alt-ergo#848, OCamlPro/alt-ergo#852, OCamlPro/alt-ergo#863, OCamlPro/alt-ergo#911, OCamlPro/alt-ergo#942, OCamlPro/alt-ergo#945, OCamlPro/alt-ergo#961, OCamlPro/alt-ergo#975, OCamlPro/alt-ergo#1069) - Expose the FPA rounding builtin in the SMT-LIB format (OCamlPro/alt-ergo#876, OCamlPro/alt-ergo#1135) - Allow changing the SAT solver using (set-option) (OCamlPro/alt-ergo#880) - Add support for the `:named` attribute (OCamlPro/alt-ergo#957) - Add support for quoted identifiers (OCamlPro/alt-ergo#909, OCamlPro/alt-ergo#972) - Add support for naming lemmas in SMT-LIB syntax (OCamlPro/alt-ergo#1141, OCamlPro/alt-ergo#1143) ### Model generation - Use post-solve SAT environment in model generation, fixing issues where incorrect models were generated (OCamlPro/alt-ergo#789) - Restore support for records in models (OCamlPro/alt-ergo#793) - Use abstract values instead of dummy values in models where the actual value does not matter (OCamlPro/alt-ergo#804, OCamlPro/alt-ergo#835) - Use fresh names for all abstract values to prevent accidental captures (OCamlPro/alt-ergo#811) - Add support for model generation with the default CDCL solver (OCamlPro/alt-ergo#829) - Support model generation for the BV theory (OCamlPro/alt-ergo#841, OCamlPro/alt-ergo#968) - Add support for optimization (MaxSMT / OptiSMT) with lexicographic Int and Real objectives (OCamlPro/alt-ergo#861, OCamlPro/alt-ergo#921) - Add a SMT-LIB printer for expressions (OCamlPro/alt-ergo#952, OCamlPro/alt-ergo#981, OCamlPro/alt-ergo#1082, OCamlPro/alt-ergo#931, OCamlPro/alt-ergo#932) - Ensure models have a value for all constants in the problem (OCamlPro/alt-ergo#1019) - Fix a rare soundness issue with integer constraints when model generation is enabled (OCamlPro/alt-ergo#1025) - Support model generation for the ADT theory (OCamlPro/alt-ergo#1093, OCamlPro/alt-ergo#1153) ### Theory reasoning - Add word-level propagators for the BV theory (OCamlPro/alt-ergo#944, OCamlPro/alt-ergo#1004, OCamlPro/alt-ergo#1007, OCamlPro/alt-ergo#1010, OCamlPro/alt-ergo#1011, OCamlPro/alt-ergo#1012, OCamlPro/alt-ergo#1040, OCamlPro/alt-ergo#1044, OCamlPro/alt-ergo#1054, OCamlPro/alt-ergo#1055, OCamlPro/alt-ergo#1056, OCamlPro/alt-ergo#1057, OCamlPro/alt-ergo#1065, OCamlPro/alt-ergo#1073, OCamlPro/alt-ergo#1144, OCamlPro/alt-ergo#1152) - Add interval domains and arithmetic propagators for the BV theory (OCamlPro/alt-ergo#1058, OCamlPro/alt-ergo#1083, OCamlPro/alt-ergo#1084, OCamlPro/alt-ergo#1085) - Native support for bv2nat of bit-vector normal forms (OCamlPro/alt-ergo#1154) - Fix incompleteness issues in the BV solver (OCamlPro/alt-ergo#978, OCamlPro/alt-ergo#979) - Abstract more arguments of AC symbols to avoid infinite loops when they contain other AC symbols (OCamlPro/alt-ergo#990) - Do not make irrelevant decisions in CDCL solver, improving performance slightly (OCamlPro/alt-ergo#1041) - Rewrite the ADT theory to use domains and integrate the enum theory into the ADT theory (OCamlPro/alt-ergo#1078, OCamlPro/alt-ergo#1086, OCamlPro/alt-ergo#1087, OCamlPro/alt-ergo#1091, OCamlPro/alt-ergo#1094, OCamlPro/alt-ergo#1138) - Rewrite the Intervals module entirely (OCamlPro/alt-ergo#1108) - Add maximize/minimize terms for matching (OCamlPro/alt-ergo#1166) - Internalize `sign_extend` and `repeat` (OCamlPro/alt-ergo#1192) - Run cross-propagators to completion (OCamlPro/alt-ergo#1221) - Support binary distinct on arbitrary bit-widths (OCamlPro/alt-ergo#1222) - Only perform optimization when building a model (OCamlPro/alt-ergo#1224) - Make sure domains do not overflow the default domain (OCamlPro/alt-ergo#1225) - Do not build unnormalized values in `zero_extend` (OCamlPro/alt-ergo#1226) ### Internal/library changes - Rewrite the Vec module (OCamlPro/alt-ergo#607) - Move printer definitions closer to type definitions (OCamlPro/alt-ergo#808) - Mark proxy names as reserved (OCamlPro/alt-ergo#836) - Use a Zarith-based representation for numbers and bit-vectors (OCamlPro/alt-ergo#850, OCamlPro/alt-ergo#943) - Add native support for (bvnot) in the BV solver (OCamlPro/alt-ergo#856) - Add constant propagators for partially interpreted functions (OCamlPro/alt-ergo#869) - Remove `Util.failwith` in favor of `Fmt.failwith` (OCamlPro/alt-ergo#872) - Add more `Expr` smart constructors (OCamlPro/alt-ergo#877, OCamlPro/alt-ergo#878) - Do not use existential variables for integer division (OCamlPro/alt-ergo#881) - Preserve `Subst` literals to prevent accidental incompleteness (OCamlPro/alt-ergo#886) - Properly start timers (OCamlPro/alt-ergo#924) - Compute a concrete representation of a model instead of performing (OCamlPro/alt-ergo#925) - Allow direct access to the SAT API in the Alt-Ergo library computations during printing (OCamlPro/alt-ergo#927) - Better handling for step limit (OCamlPro/alt-ergo#936) - Add a generic option manager to deal with the dolmen state (OCamlPro/alt-ergo#951) - Expose an imperative SAT API in the Alt-Ergo library (OCamlPro/alt-ergo#962) - Keep track of the SMT-LIB mode (OCamlPro/alt-ergo#971) - Add ability to decide on semantic literals (OCamlPro/alt-ergo#1027, OCamlPro/alt-ergo#1118) - Preserve trigger order when parsing quantifiers with multiple trigger (OCamlPro/alt-ergo#1046). - Store domains inside the union-find module (OCamlPro/alt-ergo#1119) - Remove some polymorphic hashtables (OCamlPro/alt-ergo#1219) ### Build and integration - Drop support for OCaml <4.08.1 (OCamlPro/alt-ergo#803) - Use dune-site for the inequalities plugins. External pluginsm ust now be registered through the dune-site plugin mechanism in the `(alt-ergo plugins)` site to be picked up by Alt-Ergo (OCamlPro/alt-ergo#1049). - Add a release workflow (OCamlPro/alt-ergo#827) - Add a Windows workflow (OCamlPro/alt-ergo#1203) - Mark the dune.inc file as linguist-generated to avoid huge diffs (OCamlPro/alt-ergo#830) - Use GitHub Actions badges in the README (OCamlPro/alt-ergo#882) - Use `dune build @check` to build the project (OCamlPro/alt-ergo#887) - Enable warnings as errors on the CI (OCamlPro/alt-ergo#888) - Uniformization of internal identifiers generation (OCamlPro/alt-ergo#905, OCamlPro/alt-ergo#918) - Use an efficient `String.starts_with` implementation (OCamlPro/alt-ergo#912) - Fix the Makefile (OCamlPro/alt-ergo#914) - Add `Logs` dependency (OCamlPro/alt-ergo#1206) - Use `dynamic_include` to include the generated file `dune.inc` (OCamlPro/alt-ergo#1199) - Support Windows (OCamlPro/alt-ergo#1184,OCamlPro/alt-ergo#1189,OCamlPro/alt-ergo#1195,OCamlPro/alt-ergo#1199,OCamlPro/alt-ergo#1200) - Wrap the library `Alt_ergo_prelude` (OCamlPro/alt-ergo#1223) ### Testing - Use --enable-assertions in tests (OCamlPro/alt-ergo#809) - Add a test for push/pop (OCamlPro/alt-ergo#843) - Use the CDCL solver when testing model generation (OCamlPro/alt-ergo#938) - Do not test .smt2 files with the legacy frontend (OCamlPro/alt-ergo#939) - Restore automatic creation of .expected files (OCamlPro/alt-ergo#941) ### Documentation - Add a new example for model generation (OCamlPro/alt-ergo#826) - Add a Pygments lexer for the Alt-Ergo native language (OCamlPro/alt-ergo#862) - Update the current authors (OCamlPro/alt-ergo#865) - Documentation of the `Enum` theory (OCamlPro/alt-ergo#871) - Document `Th_util.lit_origin` (OCamlPro/alt-ergo#915) - Document the CDCL-Tableaux solver (OCamlPro/alt-ergo#995) - Document Windows support (OCamlPro/alt-ergo#1216) - Remove instructions to install Alt-Ergo on Debian (OCamlPro/alt-ergo#1217) - Document optimization feature (OCamlPro/alt-ergo#1231)
This patch implements integer remainder in terms of integer division rather than the opposite. This avoids the introduction of fresh existential variables.
Fixes #875