Sls (#7439)

* reorg sls

* sls

* na

* split into base and plugin

* move sat_params to params directory, add op_def repair options

* move sat_ddfw to sls, initiate sls-bv-plugin

* porting bv-sls

* adding basic plugin

* na

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add sls-sms solver

* bv updates

* updated dependencies

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* updated dependencies

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use portable ptr-initializer

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* move definitions to cpp

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use template<> syntax

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix compiler errors for gcc

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Bump docker/build-push-action from 6.0.0 to 6.1.0 (#7265)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 6.0.0 to 6.1.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v6.0.0...v6.1.0)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* set clean shutdown for local search and re-enable local search when it parallelizes with PB solver

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Bump docker/build-push-action from 6.1.0 to 6.2.0 (#7269)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 6.1.0 to 6.2.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v6.1.0...v6.2.0)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* Fix a comment for Z3_solver_from_string (#7271)

Z3_solver_from_string accepts a string buffer with solver
assertions, not a string buffer with filename.

* trigger the build with a comment change

Signed-off-by: Lev Nachmanson <levnach@hotmail.com>

* remove macro distinction #7270

* fix #7268

* kludge to address #7232, probably superseeded by planned revision to setup/pypi

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add new ema invariant (#7288)

* Bump docker/build-push-action from 6.2.0 to 6.3.0 (#7280)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 6.2.0 to 6.3.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v6.2.0...v6.3.0)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* merge

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix unit test build

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove shared attribute

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove stale files

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix build of unit test

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes and rename sls-cc to sls-euf-plugin

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* na

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* testing / debugging arithmetic

* updates to repair logic, mainly arithmetic

* fixes to sls

* evolve sls arith

* bugfixes in sls-arith

* fix typo

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* bug fixes

* Update sls_test.cpp

* fixes

* fixes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix build

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* refactor basic plugin and clause generation

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes to ite and other

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* updates

* update

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix division by 0

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* disable fail restart

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* disable tabu when using reset moves

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* update sls_test

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add factoring

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes to semantics

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* re-add tabu override

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* generalize factoring

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix bug

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove restart

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* disable tabu in fallback modes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* localize impact of factoring

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* delay factoring

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* flatten products

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* perform lookahead update + nested mul

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* disable nested mul

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* disable nested mul, use non-lookahead

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* make reset updates recursive

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* include linear moves

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* include 5% reset probability

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* separate linear update

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* separate linear update remove 20% threshold

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove linear opt

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* enable multiplier expansion, enable linear move

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use unit coefficients for muls

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* disable non-tabu version of find_nl_moves

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove coefficient from multiplication definition

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* reorg monomials

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add smt params to path

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* avoid negative reward

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use reward as proxy for score

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use reward as proxy for score

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use exponential decay with breaks

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use std::pow

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes to bv

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes to fixed

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixup repairs

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* reserve for multiplication

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixing repair

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* include bounds checks in set random

* na

* fixes to mul

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix mul inverse

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes to handling signed operators

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* logging and fixes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* gcm

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* peli

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Add .env to gitignore to prevent environment files from being tracked

* Add m_num_pelis counter to stats in sls_context

* Remove m_num_pelis member from stats struct in sls_context

* Enhance bv_sls_eval with improved repair and logging, refine is_bv_predicate in sls_bv_plugin

* Remove verbose logging in register_term function of sls_basic_plugin and fix formatting in sls_context

* Rename source files for consistency in `src/ast/sls` directory

* Refactor bv_sls files to sls_bv with namespace and class name adjustments

* Remove typename from member declarations in bv_fixed class

* fixing conca

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Add initial implementation of bit-vector SLS evaluation module in bv_sls_eval.cpp

* Remove bv_sls_eval.cpp as part of code cleanup and refactoring

* Refactor alignment of member variables in bv_plugin of sls namespace

* Rename SLS engine related files to reflect their specific use for bit-vectors

* Refactor SLS engine and evaluator components for bit-vector specifics and adjust memory manager alignment

* Enhance bv_eval with use_current, lookahead strategies, and randomization improvements in SLS module

* Refactor verbose logging and fix logic in range adjustment functions in sls bv modules

* Remove commented verbose output in sls_bv_plugin.cpp during repair process

* Add early return after setting fixed subterms in sls_bv_fixed.cpp

* Remove redundant return statement in sls_bv_fixed.cpp

* fixes to new value propagation

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Refactor sls bv evaluation and fix logic checks for bit operations

* Add array plugin support and update bv_eval in ast_sls module

* Add array, model value, and user sort plugins to SLS module with enhancements in array propagation logic

* Refactor array_plugin in sls to improve handling of select expressions with multiple arguments

* Enhance array plugin with early termination and propagation verification, and improve euf and user sort plugins with propagation adjustments and debugging enhancements

* Add support for handling 'distinct' expressions in SLS context and user sort plugin

* Remove model value and user sort plugins from SLS theory

* replace user plugin by euf plugin

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove extra file

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Refactor handling of term registration and enhance distinct handling in sls_euf_plugin

* Add TODO list for enhancements in sls_euf_plugin.cpp

* add incremental mode

* updated package

* fix sls build

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* break sls build

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix build

* break build again

* fix build

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixing incremental

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* avoid units

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixup handling of disequality propagation

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fx

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* recover shift-weight loop

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* alternate

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* throttle save model

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* allow for alternating

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix test for new signature of flip

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* bug fixes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* restore use of value_hash

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* adding dt plugin

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* adt

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* dt updates

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* added cycle detection

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* updated sls-datatype

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* Refactor context management, improve datatype handling, and enhance logging in sls plugins.

* axiomatize dt

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add missing factory plugins to model

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixup finite domain search

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixup finite domain search

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* redo dfs

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixing model construction for underspecified operators

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes to occurs check

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixup interpretation building

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* saturate worklist

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* delay distinct axiom

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* adding model-based sls for datatatypes

* update the interface in sls_solver to transfer phase between SAT and SLS

* add value transfer option

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* rename aux functions

* Track shared variables using a unit set

* debugging parallel integration

* fix dirty flag setting

* update log level

* add plugin to smt_context, factor out sls_smt_plugin functionality.

* bug fixes

* fixes

* use common infrastructure for sls-smt

* fix build

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix build

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* remove declaration of context

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add virtual destructor

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* build warnings

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* reorder inclusion order to define smt_context before theory_sls

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* change namespace for single threaded

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* check delayed eqs before nla

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use independent completion flag for sls to avoid conflating with genuine cancelation

* validate sls-arith lemmas

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* bugfixes

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add intblast to legacy SMT solver

* fixup model generation for theory_intblast

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* na

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* mk_value needs to accept more cases where integer expression doesn't evalate

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use th-axioms to track origins of assertions

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add missing operator handling for bitwise operators

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add missing operator handling for bitwise operators

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* normalizing inequality

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* add virtual destructor

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* rework elim_unconstrained

* fix non-termination

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use glue as computed without adjustment

* update model generation to fix model bug

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fixes to model construction

* remove package and package lock

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* fix build warning

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

* use original gai

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>

---------

Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
Signed-off-by: dependabot[bot] <support@github.com>
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Sergey Bronnikov <estetus@gmail.com>
Co-authored-by: Lev Nachmanson <levnach@hotmail.com>
Co-authored-by: LiviaSun <33578456+ChuyueSun@users.noreply.github.com>

src/ast/sls/sls_smt_plugin.h

@@ -0,0 +1,158 @@
+/*++
+Copyright (c) 2024 Microsoft Corporation
+
+Module Name:
+
+    sls_smt_plugin.h
+
+Abstract:
+
+    A Stochastic Local Search (SLS) Plugin.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2024-07-10
+    
+--*/
+
+#pragma once
+
+#include "ast/sls/sls_context.h"
+#include "ast/sls/sat_ddfw.h"
+#include "util/statistics.h"
+#include <thread>
+#include <mutex>
+
+namespace sls {
+
+    class smt_context {
+    public:
+        virtual ~smt_context() {}
+        virtual ast_manager& get_manager() = 0;
+        virtual params_ref get_params() = 0;
+        virtual void initialize_value(expr* t, expr* v) = 0;
+        virtual void force_phase(sat::literal lit) = 0;
+        virtual void set_has_new_best_phase(bool b) = 0;
+        virtual bool get_best_phase(sat::bool_var v) = 0;
+        virtual expr* bool_var2expr(sat::bool_var v) = 0;
+        virtual void set_finished() = 0;
+        virtual unsigned get_num_bool_vars() const = 0;
+    };
+
+
+    //
+    // m is accessed by the main thread
+    // m_sls  is accessed by the sls thread
+    // m_sync is accessed by both
+    //
+    class smt_plugin : public sat::local_search_plugin, public sat_solver_context {
+        smt_context& ctx;
+        ast_manager& m;
+        ast_manager  m_sls;
+        ast_manager  m_sync;
+        ast_translation m_smt2sync_tr, m_smt2sls_tr;
+        expr_ref_vector m_sync_uninterp, m_sls_uninterp; 
+        expr_ref_vector m_sync_values;
+        sat::ddfw* m_ddfw = nullptr;
+        sls::context m_context;
+        std::atomic<lbool> m_result;
+        std::atomic<bool> m_completed, m_has_units;
+        std::thread m_thread;
+        std::mutex  m_mutex;
+
+        sat::literal_vector m_units;
+        model_ref m_sls_model;
+        ::statistics m_st;
+        bool m_new_clause_added = false; 
+        unsigned m_min_unsat_size = UINT_MAX;
+        obj_map<expr, expr*> m_sls2sync_uninterp; // hashtable from sls-uninterp to sync uninterp
+        obj_map<expr, expr*> m_smt2sync_uninterp; // hashtable from external uninterp to sync uninterp
+        std::atomic<bool> m_has_new_sls_values = false;
+        uint_set m_shared_bool_vars, m_shared_terms;
+        svector<bool> m_sat_phase;
+        std::atomic<bool> m_has_new_sat_phase = false;
+        std::atomic<bool> m_has_new_sls_phase = false;
+        svector<bool> m_sls_phase;
+        svector<double> m_rewards;
+        svector<sat::bool_var> m_smt_bool_var2sls_bool_var, m_sls_bool_var2smt_bool_var;
+        
+        bool is_shared(sat::literal lit);
+        void run();
+        void add_shared_term(expr* t);
+        void add_uninterp(expr* smt_t);
+        void add_shared_var(sat::bool_var v, sat::bool_var w);
+
+        void import_phase_from_smt();
+        void import_values_from_sls();
+        void export_values_from_sls();
+        void import_activity_from_sls();
+        bool export_phase_to_sls();
+        bool export_units_to_sls();
+        void export_values_to_smt();
+        void export_activity_to_smt();
+        void export_phase_to_smt();
+
+        void export_from_sls();
+
+        friend class sat::ddfw;
+        ~smt_plugin();
+
+    public:
+        smt_plugin(smt_context& ctx);
+
+        // interface to calling solver:
+        void check(expr_ref_vector const& fmls, vector <sat::literal_vector> const& clauses);
+        void finalize(model_ref& md, ::statistics& st);
+        void updt_params(params_ref& p) {}
+        std::ostream& display(std::ostream& out) override;
+
+        bool export_to_sls();
+        void import_from_sls();
+        bool completed() { return m_completed; }
+        void add_unit(sat::literal lit);
+
+        // local_search_plugin:
+        void on_restart() override {
+            if (export_to_sls())
+                m_ddfw->reinit();
+        }
+
+        void on_save_model() override;
+
+        void on_model(model_ref& mdl) override {
+            IF_VERBOSE(3, verbose_stream() << "on-model " << "\n");
+            m_sls_model = mdl;
+        }
+
+        void init_search() override {}
+
+        void finish_search() override {}
+
+        void on_rescale() override {}
+
+
+        
+        // sat_solver_context:
+        vector<sat::clause_info> const& clauses() const override { return m_ddfw->clauses(); }
+        sat::clause_info const& get_clause(unsigned idx) const override { return m_ddfw->get_clause_info(idx); }
+        ptr_iterator<unsigned> get_use_list(sat::literal lit) override { return m_ddfw->use_list(lit); }
+        void flip(sat::bool_var v) override { 
+            m_ddfw->flip(v);
+        }
+        double reward(sat::bool_var v) override { return m_ddfw->get_reward(v); }
+        double get_weigth(unsigned clause_idx) override { return m_ddfw->get_clause_info(clause_idx).m_weight; }
+        bool is_true(sat::literal lit) override { 
+            return m_ddfw->get_value(lit.var()) != lit.sign(); 
+        }
+        unsigned num_vars() const override { return m_ddfw->num_vars(); }
+        indexed_uint_set const& unsat() const override { return m_ddfw->unsat_set(); }
+        sat::bool_var add_var() override { 
+            return m_ddfw->add_var(); 
+        }
+        void add_clause(unsigned n, sat::literal const* lits) override { 
+            m_ddfw->add(n, lits);
+            m_new_clause_added = true;
+        }
+        void force_restart() override { m_ddfw->force_restart(); }
+    };
+}