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https://github.com/Z3Prover/z3
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524 lines
17 KiB
C++
524 lines
17 KiB
C++
/*++
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Copyright (c) 2008 Microsoft Corporation
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Module Name:
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theory_diff_logic.h
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Abstract:
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<abstract>
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Author:
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Leonardo de Moura (leonardo) 2008-04-21.
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Nikolaj Bjorner (nbjorner) 2008-05-05
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Revision History:
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TODO:
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- check regressions with smt::solver.
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- what should be done properly (during internalization) for reflect()
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- fix theory propagation:
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- x <= y + 2, then x <= y + 3
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- x = y, then x <= y + 2
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- x = y, x <= z <= y, then x = z
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- fix/add equality propagation
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- add relaxation (somewhat easy)
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- Currently stored explanation in edges is stored at creation time
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(not at propagation time).
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Is this flexible enough for processing equalities?
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- eq_justification present in smt::context when calling new_eq_eh.
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pass such to the edge?
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- context::assume_eq is absent.
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- context::add_eq and context::push_eq are protected. Cannot propagate equalities back to core.
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-
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--*/
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#ifndef _THEORY_DIFF_LOGIC_H_
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#define _THEORY_DIFF_LOGIC_H_
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#include"rational.h"
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#include"inf_rational.h"
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#include"inf_int_rational.h"
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#include"s_integer.h"
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#include"inf_s_integer.h"
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#include"smt_theory.h"
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#include"diff_logic.h"
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#include"arith_decl_plugin.h"
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#include"smt_justification.h"
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#include"map.h"
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#include"front_end_params.h"
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#include"arith_eq_adapter.h"
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#include"smt_model_generator.h"
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#include"numeral_factory.h"
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#include"smt_clause.h"
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// The DL theory can represent term such as n + k, where n is an enode and k is a numeral.
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namespace smt {
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struct theory_diff_logic_statistics {
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unsigned m_num_conflicts;
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unsigned m_num_assertions;
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unsigned m_num_th2core_eqs;
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unsigned m_num_th2core_prop;
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unsigned m_num_core2th_eqs;
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unsigned m_num_core2th_diseqs;
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unsigned m_num_core2th_new_diseqs;
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void reset() {
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m_num_conflicts = 0;
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m_num_assertions = 0;
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m_num_th2core_prop = 0;
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m_num_th2core_eqs = 0;
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m_num_core2th_eqs = 0;
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m_num_core2th_diseqs = 0;
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m_num_core2th_new_diseqs = 0;
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}
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theory_diff_logic_statistics() {
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reset();
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}
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};
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class dl_conflict : public simple_justification {
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public:
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dl_conflict(region & r, unsigned nls, literal const * lits): simple_justification(r, nls, lits) { }
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virtual proof * mk_proof(conflict_resolution & cr) { NOT_IMPLEMENTED_YET(); return 0; }
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};
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class dl_propagate : public simple_justification {
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public:
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dl_propagate(region & r, unsigned nls, literal const * lits): simple_justification(r, nls, lits) { }
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virtual proof * mk_proof(conflict_resolution & cr) { NOT_IMPLEMENTED_YET(); return 0; }
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};
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template<typename Ext>
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class theory_diff_logic : public theory, private Ext {
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typedef typename Ext::numeral numeral;
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class implied_eq_justification : public justification {
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theory_diff_logic & m_theory;
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theory_var m_v1;
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theory_var m_v2;
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unsigned m_timestamp;
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public:
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implied_eq_justification(theory_diff_logic & theory, theory_var v1, theory_var v2, unsigned ts):
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m_theory(theory),
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m_v1(v1),
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m_v2(v2),
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m_timestamp(ts) {
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}
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virtual void get_antecedents(conflict_resolution & cr) {
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m_theory.get_eq_antecedents(m_v1, m_v2, m_timestamp, cr);
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}
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virtual proof * mk_proof(conflict_resolution & cr) { NOT_IMPLEMENTED_YET(); return 0; }
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};
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class implied_bound_justification : public justification {
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theory_diff_logic& m_theory;
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edge_id m_subsumed_edge;
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edge_id m_bridge_edge;
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public:
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implied_bound_justification(theory_diff_logic & theory, edge_id se, edge_id be):
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m_theory(theory),
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m_subsumed_edge(se),
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m_bridge_edge(be) {
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}
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virtual void get_antecedents(conflict_resolution & cr) {
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m_theory.get_implied_bound_antecedents(m_bridge_edge, m_subsumed_edge, cr);
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}
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virtual proof * mk_proof(conflict_resolution & cr) { NOT_IMPLEMENTED_YET(); return 0; }
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};
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enum atom_kind {
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LE_ATOM,
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EQ_ATOM
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};
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class atom {
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protected:
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atom_kind m_kind;
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bool_var m_bvar;
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bool m_true;
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public:
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atom(atom_kind k, bool_var bv) : m_kind(k), m_bvar(bv), m_true(false) {}
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virtual ~atom() {}
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atom_kind kind() const { return m_kind; }
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bool_var get_bool_var() const { return m_bvar; }
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bool is_true() const { return m_true; }
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void assign_eh(bool is_true) { m_true = is_true; }
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virtual std::ostream& display(theory_diff_logic const& th, std::ostream& out) const;
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};
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class le_atom : public atom {
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int m_pos;
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int m_neg;
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public:
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le_atom(bool_var bv, int pos, int neg):
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atom(LE_ATOM, bv),
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m_pos(pos),
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m_neg(neg) {
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}
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virtual ~le_atom() {}
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int get_asserted_edge() const { return this->m_true?m_pos:m_neg; }
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int get_pos() const { return m_pos; }
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int get_neg() const { return m_neg; }
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virtual std::ostream& display(theory_diff_logic const& th, std::ostream& out) const;
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};
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class eq_atom : public atom {
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app_ref m_le;
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app_ref m_ge;
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public:
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eq_atom(bool_var bv, app_ref& le, app_ref& ge):
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atom(EQ_ATOM, bv),
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m_le(le),
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m_ge(ge)
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{}
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virtual ~eq_atom() {}
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virtual std::ostream& display(theory_diff_logic const& th, std::ostream& out) const;
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app* get_le() const { return m_le.get(); }
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app* get_ge() const { return m_ge.get(); }
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};
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typedef ptr_vector<atom> atoms;
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typedef u_map<atom*> bool_var2atom;
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// Auxiliary info for propagating cheap equalities
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class eq_prop_info {
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int m_scc_id;
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numeral m_delta;
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theory_var m_root;
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public:
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eq_prop_info(int scc_id, const numeral & d, theory_var r = null_theory_var):
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m_scc_id(scc_id),
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m_delta(d),
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m_root(r) {
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}
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theory_var get_root() const {
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return m_root;
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}
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unsigned hash() const { return mk_mix(static_cast<unsigned>(m_scc_id), m_delta.hash(), 0x9e3779b9); }
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bool operator==(const eq_prop_info & info) const {
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return m_scc_id == info.m_scc_id && m_delta == info.m_delta;
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}
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};
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struct eq_prop_info_hash_proc {
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unsigned operator()(eq_prop_info * info) const {
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return info->hash();
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}
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};
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struct eq_prop_info_eq_proc {
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bool operator()(eq_prop_info * info1, eq_prop_info * info2) const {
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return *info1 == *info2;
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}
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};
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typedef ptr_hashtable<eq_prop_info, eq_prop_info_hash_proc, eq_prop_info_eq_proc> eq_prop_info_set;
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// Extension for diff_logic core.
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struct GExt : public Ext {
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typedef literal explanation;
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};
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// Functor used to collect the proofs for a conflict due to
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// a negative cycle.
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class nc_functor {
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literal_vector m_antecedents;
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theory_diff_logic& m_super;
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public:
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nc_functor(theory_diff_logic& s) : m_super(s) {}
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void reset();
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literal_vector const& get_lits() const { return m_antecedents; }
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void operator()(literal const & ex) {
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if (ex != null_literal) {
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m_antecedents.push_back(ex);
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}
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}
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void new_edge(dl_var src, dl_var dst, unsigned num_edges, edge_id const* edges) {
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m_super.new_edge(src, dst, num_edges, edges);
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}
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};
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struct scope {
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unsigned m_atoms_lim;
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unsigned m_asserted_atoms_lim;
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unsigned m_asserted_qhead_old;
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};
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class theory_diff_logic_del_eh : public clause_del_eh {
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theory_diff_logic& m_super;
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public:
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theory_diff_logic_del_eh(theory_diff_logic& s) : m_super(s) {}
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virtual ~theory_diff_logic_del_eh() {}
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virtual void operator()(ast_manager&, clause* cls) {
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TRACE("dl_activity", tout << "deleting " << cls << "\n";);
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m_super.del_clause_eh(cls);
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dealloc(this);
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}
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};
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front_end_params & m_params;
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arith_util m_util;
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arith_eq_adapter m_arith_eq_adapter;
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theory_diff_logic_statistics m_stats;
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dl_graph<GExt> m_graph;
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theory_var m_zero_int; // cache the variable representing the zero variable.
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theory_var m_zero_real; // cache the variable representing the zero variable.
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int_vector m_scc_id; // Cheap equality propagation
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bool m_modified_since_eq_prop; // true if new constraints were asserted
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// since last eq propagation.
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eq_prop_info_set m_eq_prop_info_set; // set of existing equality prop infos
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ptr_vector<eq_prop_info> m_eq_prop_infos;
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ptr_vector<atom> m_atoms;
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ptr_vector<atom> m_asserted_atoms; // set of asserted atoms
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unsigned m_asserted_qhead;
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bool_var2atom m_bool_var2atom;
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svector<scope> m_scopes;
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unsigned m_num_core_conflicts;
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unsigned m_num_propagation_calls;
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double m_agility;
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bool m_is_lia;
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bool m_non_diff_logic_exprs;
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arith_factory * m_factory;
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rational m_delta;
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nc_functor m_nc_functor;
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// Set a conflict due to a negative cycle.
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void set_neg_cycle_conflict();
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void new_edge(dl_var src, dl_var dst, unsigned num_edges, edge_id const* edges);
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// Create a new theory variable.
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virtual theory_var mk_var(enode* n);
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virtual theory_var mk_var(app* n);
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void mark_as_modified_since_eq_prop();
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void unmark_as_modified_since_eq_prop();
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bool propagate_cheap_equalities();
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void compute_delta();
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void found_non_diff_logic_expr(expr * n);
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bool is_interpreted(app* n) const;
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void del_clause_eh(clause* cls);
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public:
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theory_diff_logic(ast_manager& m, front_end_params & params):
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theory(m.get_family_id("arith")),
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m_params(params),
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m_util(m),
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m_arith_eq_adapter(*this, params, m_util),
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m_zero_int(null_theory_var),
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m_zero_real(null_theory_var),
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m_modified_since_eq_prop(false),
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m_asserted_qhead(0),
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m_num_core_conflicts(0),
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m_num_propagation_calls(0),
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m_agility(0.5),
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m_is_lia(true),
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m_non_diff_logic_exprs(false),
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m_factory(0),
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m_nc_functor(*this) {
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}
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~theory_diff_logic() {
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reset_eh();
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}
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virtual theory * mk_fresh(context * new_ctx) { return alloc(theory_diff_logic, get_manager(), m_params); }
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virtual char const * get_name() const { return "difference-logic"; }
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/**
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\brief See comment in theory::mk_eq_atom
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*/
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virtual app * mk_eq_atom(expr * lhs, expr * rhs) { return m_util.mk_eq(lhs, rhs); }
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virtual void init(context * ctx);
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virtual bool internalize_atom(app * atom, bool gate_ctx);
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virtual bool internalize_term(app * term);
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virtual void internalize_eq_eh(app * atom, bool_var v);
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virtual void assign_eh(bool_var v, bool is_true);
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virtual void new_eq_eh(theory_var v1, theory_var v2);
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virtual bool use_diseqs() const { return true; }
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virtual void new_diseq_eh(theory_var v1, theory_var v2);
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virtual void push_scope_eh();
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virtual void pop_scope_eh(unsigned num_scopes);
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virtual void restart_eh() {
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m_arith_eq_adapter.restart_eh();
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}
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virtual void relevant_eh(app* e);
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virtual void init_search_eh() {
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m_arith_eq_adapter.init_search_eh();
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}
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virtual final_check_status final_check_eh();
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virtual bool is_shared(theory_var v) const {
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return false;
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}
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virtual bool can_propagate() {
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return m_asserted_qhead != m_asserted_atoms.size();
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}
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virtual void propagate();
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virtual justification * why_is_diseq(theory_var v1, theory_var v2) {
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NOT_IMPLEMENTED_YET();
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return 0;
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}
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// virtual void flush_eh();
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virtual void reset_eh();
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virtual void init_model(model_generator & m);
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virtual model_value_proc * mk_value(enode * n, model_generator & mg);
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virtual bool validate_eq_in_model(theory_var v1, theory_var v2, bool is_true) const;
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virtual void display(std::ostream & out) const;
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virtual void collect_statistics(::statistics & st) const;
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private:
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virtual void new_eq_eh(theory_var v1, theory_var v2, justification& j);
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virtual void new_diseq_eh(theory_var v1, theory_var v2, justification& j);
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bool is_negative(app* n, app*& m);
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void del_atoms(unsigned old_size);
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void propagate_core();
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bool propagate_atom(atom* a);
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theory_var mk_term(app* n);
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theory_var mk_num(app* n, rational const& r);
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bool is_offset(app* n, app*& v, app*& offset, rational& r);
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bool is_consistent() const;
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bool reflect() const { return m_params.m_arith_reflect; }
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bool theory_resolve() const { return m_params.m_theory_resolve; }
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unsigned lazy_pivoting_lvl() const { return m_params.m_arith_lazy_pivoting_lvl; }
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bool propagate_eqs() const { return m_params.m_arith_propagate_eqs; }
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bool dump_lemmas() const { return m_params.m_arith_dump_lemmas; }
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theory_var expand(bool pos, theory_var v, rational & k);
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void new_eq_or_diseq(bool is_eq, theory_var v1, theory_var v2, justification& eq_just);
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void get_eq_antecedents(theory_var v1, theory_var v2, unsigned timestamp, conflict_resolution & cr);
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void get_implied_bound_antecedents(edge_id bridge_edge, edge_id subsumed_edge, conflict_resolution & cr);
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theory_var get_zero(sort* s) const { return m_util.is_int(s)?m_zero_int:m_zero_real; }
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theory_var get_zero(expr* e) const { return get_zero(get_manager().get_sort(e)); }
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void inc_conflicts();
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};
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struct idl_ext {
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// TODO: It doesn't need to be a rational, but a bignum integer.
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static const bool m_int_theory = true;
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typedef rational numeral;
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numeral m_epsilon;
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idl_ext() : m_epsilon(1) {}
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};
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struct sidl_ext {
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// TODO: It doesn't need to be a rational, but a bignum integer.
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static const bool m_int_theory = true;
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typedef s_integer numeral;
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numeral m_epsilon;
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sidl_ext() : m_epsilon(1) {}
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};
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struct rdl_ext {
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static const bool m_int_theory = false;
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typedef inf_int_rational numeral;
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numeral m_epsilon;
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rdl_ext() : m_epsilon(rational(), true) {}
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};
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struct srdl_ext {
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static const bool m_int_theory = false;
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typedef inf_s_integer numeral;
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numeral m_epsilon;
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srdl_ext() : m_epsilon(s_integer(0),true) {}
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};
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typedef theory_diff_logic<idl_ext> theory_idl;
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typedef theory_diff_logic<sidl_ext> theory_fidl;
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typedef theory_diff_logic<rdl_ext> theory_rdl;
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typedef theory_diff_logic<srdl_ext> theory_frdl;
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};
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#endif /* _THEORY_DIFF_LOGIC_H_ */
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