fix drat checker

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

src/sat/sat_parallel.h

@@ -0,0 +1,91 @@
+/*++
+Copyright (c) 2017 Microsoft Corporation
+
+Module Name:
+
+    sat_parallel.h
+
+Abstract:
+
+    Utilities for parallel SAT solving.
+
+Author:
+
+    Nikolaj Bjorner (nbjorner) 2017-1-29.
+
+Revision History:
+
+--*/
+#ifndef SAT_PAR_H_
+#define SAT_PAR_H_
+
+#include"sat_types.h"
+#include"hashtable.h"
+#include"map.h"
+#include"rlimit.h"
+
+namespace sat {
+
+    class parallel {
+
+        // shared pool of learned clauses.
+        class vector_pool {
+            unsigned_vector m_vectors;
+            unsigned        m_size;
+            unsigned        m_tail;
+            unsigned_vector m_heads;
+            void next(unsigned& index);
+            unsigned get_owner(unsigned index) const { return m_vectors[index]; }
+            unsigned get_length(unsigned index) const { return m_vectors[index+1]; }
+            unsigned const* get_ptr(unsigned index) const { return m_vectors.c_ptr() + index + 2; }
+        public:
+            vector_pool() {}
+            void reserve(unsigned num_owners, unsigned sz);
+            void begin_add_vector(unsigned owner, unsigned n);
+            void add_vector_elem(unsigned e);
+            bool get_vector(unsigned owner, unsigned& n, unsigned const*& ptr);
+        };
+
+        bool enable_add(clause const& c) const;
+        void _get_clauses(solver& s);
+
+        typedef hashtable<unsigned, u_hash, u_eq> index_set;
+        literal_vector m_units;
+        index_set      m_unit_set;
+        literal_vector m_lits;
+        vector_pool    m_pool;
+
+        scoped_limits      m_scoped_rlimit;
+        vector<reslimit>   m_limits;
+        ptr_vector<solver> m_solvers;
+        
+    public:
+
+        parallel(solver& s);
+
+        ~parallel();
+
+        void init_solvers(solver& s, unsigned num_extra_solvers);
+
+        // reserve space
+        void reserve(unsigned num_owners, unsigned sz) { m_pool.reserve(num_owners, sz); }
+
+        solver& get_solver(unsigned i) { return *m_solvers[i]; }
+
+        void cancel_solver(unsigned i) { m_limits[i].cancel(); }
+
+        // exchange unit literals
+        void exchange(solver& s, literal_vector const& in, unsigned& limit, literal_vector& out);
+
+        // add clause to shared clause pool
+        void share_clause(solver& s, clause const& c);
+
+        void share_clause(solver& s, literal l1, literal l2);
+        
+        // receive clauses from shared clause pool
+        void get_clauses(solver& s);
+    };
+
+};
+
+#endif