include chronological backtracking, two-phase sat, xor inprocessing, probsat, ddfw

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

src/sat/sat_prob.h

@@ -0,0 +1,160 @@
+/*++
+  Copyright (c) 2019 Microsoft Corporation
+
+  Module Name:
+
+   sat_prob.h
+
+  Abstract:
+   
+    PROB Local search module for clauses
+
+  Author:
+
+  Nikolaj Bjorner 2019-4-23
+
+  Notes:
+  
+     http://www.ict.griffith.edu.au/~johnt/publications/CP2006raouf.pdf
+
+  --*/
+#ifndef _SAT_PROB_
+#define _SAT_PROB_
+
+#include "util/uint_set.h"
+#include "util/rlimit.h"
+#include "sat/sat_clause.h"
+#include "sat/sat_types.h"
+
+namespace sat {
+    class solver;
+
+    class prob : public i_local_search {
+
+        struct clause_info {
+            clause_info(): m_trues(0), m_num_trues(0) {}
+            unsigned m_trues;        // set of literals that are true
+            unsigned m_num_trues;    // size of true set
+            bool is_true() const { return m_num_trues > 0; }
+            void add(literal lit) { ++m_num_trues; m_trues += lit.index(); }
+            void del(literal lit) { SASSERT(m_num_trues > 0); --m_num_trues; m_trues -= lit.index(); }
+        };
+
+        struct config {
+            unsigned m_prob_random_init;
+            unsigned m_restart_offset;
+            double   m_cb;
+            double   m_eps;
+            config() { reset(); }
+            void reset() {
+                m_prob_random_init = 4;
+                m_restart_offset = 1000000;
+                m_cb = 2.85;
+                m_eps = 0.9;
+            }
+        };
+        
+        config           m_config;
+        reslimit         m_limit;
+        clause_allocator m_alloc;
+        clause_vector    m_clause_db;     
+        svector<clause_info> m_clauses;
+        svector<bool>    m_values, m_best_values;
+        unsigned         m_best_min_unsat;
+        vector<unsigned_vector> m_use_list;
+        unsigned_vector  m_flat_use_list;
+        unsigned_vector  m_use_list_index;
+        svector<double>  m_prob_break;
+        svector<double>  m_probs;
+        indexed_uint_set m_unsat;
+        random_gen       m_rand;
+        unsigned_vector  m_breaks;
+        uint64_t         m_flips;
+        uint64_t         m_next_restart;
+        unsigned         m_restart_count;
+        stopwatch        m_stopwatch;
+        model            m_model;
+
+        class use_list {
+            prob& p;
+            unsigned i;
+        public:
+            use_list(prob& p, literal lit):
+                p(p), i(lit.index()) {}
+            unsigned const* begin() { return p.m_flat_use_list.c_ptr() + p.m_use_list_index[i]; }
+            unsigned const* end() { return p.m_flat_use_list.c_ptr() + p.m_use_list_index[i+1]; }
+        };
+
+        void flatten_use_list(); 
+
+        bool is_true(literal lit) const { return m_values[lit.var()] != lit.sign(); }
+
+        inline clause const& get_clause(unsigned idx) const { return *m_clause_db[idx]; }
+
+        inline bool is_true(unsigned idx) const { return m_clauses[idx].is_true(); }
+
+        inline void inc_break(literal lit) { m_breaks[lit.var()]++; }
+
+        inline void dec_break(literal lit) { m_breaks[lit.var()]--; }
+
+        void flip();
+
+        bool_var pick_var();
+
+        void flip(bool_var v);
+
+        void reinit_values();
+
+        void save_best_values();
+
+        void init();
+
+        void init_random_values();
+
+        void init_best_values();
+
+        void init_near_best_values();
+
+        void init_clauses();
+
+        void auto_config();
+
+        bool should_restart();
+
+        void do_restart();
+
+        void invariant();
+
+        void log();
+
+        void add(unsigned sz, literal const* c);
+
+    public:
+        prob() {}
+
+        ~prob() override;
+
+        lbool check(unsigned sz, literal const* assumptions, parallel* p) override;
+
+        void set_seed(unsigned n) override { m_rand.set_seed(n); }
+
+        reslimit& rlimit() override { return m_limit; }
+
+        void add(solver const& s) override;
+
+        model const& get_model() const override { return m_model; }
+       
+        std::ostream& display(std::ostream& out) const;
+
+        void updt_params(params_ref const& p) override {}
+
+        unsigned num_non_binary_clauses() const override { return 0; }
+
+        void collect_statistics(statistics& st) const override {} 
+
+        void reinit(solver& s) override { UNREACHABLE(); }
+
+    };
+}
+
+#endif