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WIP revamp conflict state

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2022-01-29 16:17:58 -08:00
parent 60248d0981
commit b488a1fadd
6 changed files with 50 additions and 55 deletions
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34
src/math/polysat/conflict.h
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@ -10,6 +10,37 @@ Author:
Nikolaj Bjorner (nbjorner) 2021-03-19
Jakob Rath 2021-04-6
Notes:
A conflict state is of the form <Vars, Constraints>
Where Vars are shorthand for the constraints v = value(v) for v in Vars and value(v) is the assignent.
The conflict state is unsatisfiable under background clauses F.
Dually, the negation is a consequence of F.
Conflict resolution resolves an assignment in the search stack against the conflict state.
Assignments are of the form:
lit <- D => lit - lit is propagated by the clause D => lit
lit <- ? - lit is a decision literal.
lit <- asserted - lit is asserted
lit <- Vars - lit is propagated from variable evaluation.
v = value <- Cs - v is assigned value by constraints Cs
v = value <- ? - v is a decision literal.
- All literals should be assigned in the stack prior to their use.
lit <- D => lit, < Vars, { lit } u Cs > ===> < Vars, Cs u D >
lit <- ?, < Vars, { lit } u Cs > ===> ~lit <- (Cs & Vars = value(Vars) => ~lit)
lit <- asserted, < Vars, { lit } u Cs > ===> accumulate lit for a core
lit <- Vars', < Vars, { lit } u Cs > ===> ~lit <- (Cs & Vars = value(Vars) => ~lit)
v = value <- Cs, < Vars u { v }, Cs > ===>
--*/
#pragma once
#include "math/polysat/constraint.h"
@ -77,7 +108,7 @@ namespace polysat {
void reset();
bool is_pmarked(pvar v) const;
bool contains_pvar(pvar v) const { return m_vars.contains(v); }
bool is_bmarked(sat::bool_var b) const;
/** conflict because the constraint c is false under current variable assignment */
@ -88,6 +119,7 @@ namespace polysat {
void set(clause const& cl);
void insert(signed_constraint c);
void insert_vars(signed_constraint c);
void insert(signed_constraint c, vector<signed_constraint> const& premises);
void remove(signed_constraint c);
void replace(signed_constraint c_old, signed_constraint c_new, vector<signed_constraint> const& c_new_premises);