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e005838129
Otherwise, e.g. when adding axioms, the caller would have to check each literal before adding it.
61 lines
1.8 KiB
C++
61 lines
1.8 KiB
C++
/*++
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Copyright (c) 2021 Microsoft Corporation
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Module Name:
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polysat clause builder
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Author:
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Jakob Rath 2021-04-6
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Notes:
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Builds a clause from literals and constraints.
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Takes care to
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- resolve with unit clauses and accumulate their dependencies,
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- skip trivial new constraints such as "4 <= 1".
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--*/
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#pragma once
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#include "math/polysat/constraint.h"
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#include "math/polysat/types.h"
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namespace polysat {
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class clause_builder {
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solver* m_solver;
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sat::literal_vector m_literals;
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/// true iff clause contains a literal that is always true
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/// (only this specific case of tautology is covered by this flag)
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bool m_is_tautology = false;
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public:
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clause_builder(solver& s);
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clause_builder(clause_builder const& s) = delete;
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clause_builder(clause_builder&& s) = default;
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clause_builder& operator=(clause_builder const& s) = delete;
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clause_builder& operator=(clause_builder&& s) = default;
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bool empty() const { return m_literals.empty() && !m_is_tautology; }
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void reset();
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/// Build the clause. This will reset the clause builder so it can be reused.
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/// Returns nullptr if the clause is a tautology and should not be added to the solver.
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clause_ref build();
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void push(sat::literal lit);
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void push(signed_constraint c);
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void push(inequality const& i) { push(i.as_signed_constraint()); }
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/// Push a new constraint. Allocates a boolean variable for the constraint, if necessary.
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void push_new(signed_constraint c);
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using const_iterator = decltype(m_literals)::const_iterator;
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const_iterator begin() const { return m_literals.begin(); }
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const_iterator end() const { return m_literals.end(); }
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};
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}
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