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9fc4015c46
Removing ternary clause optimization from sat_solver simplifies special case handling of ternary clauses throughout the sat solver and dependent solvers (pb_solver). Benchmarking on QF_BV suggests the ternary clause optimization does not have any effect. While removing ternary clause optimization two bugs in unit propagation were also uncovered: it missed propagations when the only a single undef literal remained in the non-watched literals and it did not update blocked literals in cases where it could in the watch list. These performance bugs were for general clauses, ternary clause propagation did not miss propagations (and don't use blocked literals), but fixing these issues for general clauses appear to have made ternary clause optimization irrelevant based on what was measured.
76 lines
2.3 KiB
C++
76 lines
2.3 KiB
C++
/*++
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Copyright (c) 2011 Microsoft Corporation
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Module Name:
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sat_justification.h
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Abstract:
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Justifications for SAT assignments
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Author:
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Leonardo de Moura (leonardo) 2011-05-21.
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Revision History:
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--*/
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#pragma once
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namespace sat {
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class justification {
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public:
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enum kind { NONE = 0, BINARY = 1, CLAUSE = 2, EXT_JUSTIFICATION = 3};
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private:
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unsigned m_level;
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size_t m_val1;
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unsigned m_val2;
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justification(unsigned lvl, ext_justification_idx idx, kind k):m_level(lvl), m_val1(idx), m_val2(k) {}
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unsigned val1() const { return static_cast<unsigned>(m_val1); }
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public:
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justification(unsigned lvl):m_level(lvl), m_val1(0), m_val2(NONE) {}
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explicit justification(unsigned lvl, literal l):m_level(lvl), m_val1(l.to_uint()), m_val2(BINARY) {}
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explicit justification(unsigned lvl, clause_offset cls_off):m_level(lvl), m_val1(cls_off), m_val2(CLAUSE) {}
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static justification mk_ext_justification(unsigned lvl, ext_justification_idx idx) { return justification(lvl, idx, EXT_JUSTIFICATION); }
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unsigned level() const { return m_level; }
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kind get_kind() const { return static_cast<kind>(m_val2 & 7); }
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bool is_none() const { return m_val2 == NONE; }
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bool is_binary_clause() const { return m_val2 == BINARY; }
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literal get_literal() const { SASSERT(is_binary_clause()); return to_literal(val1()); }
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bool is_clause() const { return m_val2 == CLAUSE; }
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clause_offset get_clause_offset() const { return m_val1; }
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bool is_ext_justification() const { return m_val2 == EXT_JUSTIFICATION; }
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ext_justification_idx get_ext_justification_idx() const { return m_val1; }
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};
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inline std::ostream & operator<<(std::ostream & out, justification const & j) {
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switch (j.get_kind()) {
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case justification::NONE:
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out << "none";
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break;
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case justification::BINARY:
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out << "binary " << j.get_literal();
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break;
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case justification::CLAUSE:
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out << "clause";
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break;
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case justification::EXT_JUSTIFICATION:
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out << "external";
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break;
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}
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out << " @" << j.level();
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return out;
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}
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};
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