Z3 sources

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>

lib/sat_probing.h

@@ -0,0 +1,92 @@
+/*++
+Copyright (c) 2011 Microsoft Corporation
+
+Module Name:
+
+    sat_probing.h
+
+Abstract:
+
+    Probing (aka failed literal detection).
+
+
+Author:
+
+    Leonardo de Moura (leonardo) 2011-06-04.
+
+Revision History:
+
+--*/
+#ifndef _SAT_PROBING_H_
+#define _SAT_PROBING_H_
+
+#include"sat_types.h"
+#include"params.h"
+#include"statistics.h"
+
+namespace sat {
+
+    class probing {
+        solver &        s;
+        unsigned        m_stopped_at;  // where did it stop
+        literal_set     m_assigned;    // literals assigned in the first branch
+        literal_vector  m_to_assert;
+
+        // counters
+        int             m_counter;       // track cost
+
+        // config
+        bool               m_probing;             // enabled/disabled
+        unsigned           m_probing_limit;       // max cost per round
+        bool               m_probing_cache;       // cache implicit binary clauses
+        bool               m_probing_binary;      // try l1 and l2 for binary clauses l1 \/ l2
+        unsigned long long m_probing_cache_limit; // memory limit for enabling caching.
+
+        // stats
+        unsigned           m_num_assigned;
+        
+        struct cache_entry {
+            bool           m_available;
+            literal_vector m_lits; 
+            cache_entry():m_available(false) {}
+        };
+
+        vector<cache_entry> m_cached_bins;  
+
+        struct report;
+
+        void reset_cache(literal l);
+        void cache_bins(literal l, unsigned old_tr_sz);
+        bool try_lit(literal l, bool updt_cache);
+        void process(bool_var v);
+        void process_core(bool_var v);
+
+    public:
+        probing(solver & s, params_ref const & p);
+        
+        bool operator()(bool force = false);
+
+        void updt_params(params_ref const & p);
+        static void collect_param_descrs(param_descrs & d);
+
+        void free_memory();
+
+        void collect_statistics(statistics & st);
+        void reset_statistics();
+
+        // return the literals implied by l.
+        // return 0, if the cache is not available
+        literal_vector * cached_implied_lits(literal l) {
+            if (!m_probing_cache) return 0;
+            if (l.index() >= m_cached_bins.size()) return 0;
+            cache_entry & e = m_cached_bins[l.index()];
+            if (!e.m_available) return 0;
+            return &(e.m_lits);
+        }
+
+        void dec(unsigned c) { m_counter -= c; }
+    };
+
+};
+
+#endif