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sat solver setup

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Signed-off-by: Nikolaj Bjorner <nbjorner@microsoft.com>
This commit is contained in:
Nikolaj Bjorner 2020-08-26 09:40:31 -07:00
parent 78b88f761c
commit c21a2fcf9f
28 changed files with 984 additions and 441 deletions
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8
scripts/mk_project.py
View file

@ -37,9 +37,11 @@ def init_project_def():
add_lib('parser_util', ['ast'], 'parsers/util')
add_lib('proofs', ['rewriter', 'util'], 'ast/proofs')
add_lib('solver', ['model', 'tactic', 'proofs'])
add_lib('cmd_context', ['solver', 'rewriter'])
add_lib('sat_tactic', ['tactic', 'sat', 'solver'], 'sat/tactic')
add_lib('sat_euf', ['sat_tactic', 'sat', 'euf'], 'sat/euf')
add_lib('cmd_context', ['solver', 'rewriter'])
add_lib('sat_smt', ['sat', 'tactic'], 'sat/smt')
add_lib('sat_ba', ['sat', 'sat_smt'], 'sat/ba')
add_lib('sat_euf', ['sat', 'euf', 'sat_ba'], 'sat/euf')
add_lib('sat_tactic', ['tactic', 'sat', 'solver', 'sat_euf'], 'sat/tactic')
add_lib('smt2parser', ['cmd_context', 'parser_util'], 'parsers/smt2')
add_lib('pattern', ['normal_forms', 'smt2parser', 'rewriter'], 'ast/pattern')
add_lib('core_tactics', ['tactic', 'macros', 'normal_forms', 'rewriter', 'pattern'], 'tactic/core')

4
src/CMakeLists.txt
View file

@ -59,8 +59,10 @@ add_subdirectory(tactic/core)
add_subdirectory(math/subpaving/tactic)
add_subdirectory(tactic/aig)
add_subdirectory(solver)
add_subdirectory(sat/tactic)
add_subdirectory(sat/smt)
add_subdirectory(sat/ba)
add_subdirectory(sat/euf)
add_subdirectory(sat/tactic)
add_subdirectory(tactic/arith)
add_subdirectory(nlsat/tactic)
add_subdirectory(ackermannization)

63
src/ast/euf/euf_egraph.cpp
View file

@ -17,6 +17,7 @@ Author:
#include "ast/euf/euf_egraph.h"
#include "ast/ast_pp.h"
#include "ast/ast_translation.h"
namespace euf {
@ -60,8 +61,10 @@ namespace euf {
void egraph::reinsert_equality(enode* p) {
SASSERT(is_equality(p));
if (p->get_arg(0)->get_root() == p->get_arg(1)->get_root())
if (p->get_arg(0)->get_root() == p->get_arg(1)->get_root()) {
m_new_eqs.push_back(p);
++m_stats.m_num_eqs;
}
}
bool egraph::is_equality(enode* p) const {
@ -162,6 +165,7 @@ namespace euf {
enode* r2 = n2->get_root();
if (r1 == r2)
return;
++m_stats.m_num_merge;
if (r1->interpreted() && r2->interpreted()) {
set_conflict(n1, n2, j);
return;
@ -170,8 +174,10 @@ namespace euf {
std::swap(r1, r2);
std::swap(n1, n2);
}
if ((m.is_true(r2->get_owner()) || m.is_false(r2->get_owner())) && j.is_congruence())
if ((m.is_true(r2->get_owner()) || m.is_false(r2->get_owner())) && j.is_congruence()) {
m_new_lits.push_back(n1);
++m_stats.m_num_lits;
}
for (enode* p : enode_parents(n1))
m_table.erase(p);
for (enode* p : enode_parents(n2))
@ -211,6 +217,7 @@ namespace euf {
}
void egraph::set_conflict(enode* n1, enode* n2, justification j) {
++m_stats.m_num_conflicts;
if (m_inconsistent)
return;
m_inconsistent = true;
@ -305,7 +312,8 @@ namespace euf {
template <typename T>
void egraph::explain_eq(ptr_vector<T>& justifications, enode* a, enode* b, bool comm) {
SASSERT(m_todo.empty());
push_congruence(a, b, comm);
SASSERT(a->get_root() == b->get_root());
push_lca(a, b);
explain_todo(justifications);
}
@ -330,6 +338,10 @@ namespace euf {
std::ostream& egraph::display(std::ostream& out) const {
m_table.display(out);
unsigned max_args = 0;
for (enode* n : m_nodes)
max_args = std::max(max_args, n->num_args());
for (enode* n : m_nodes) {
out << std::setw(5)
<< n->get_owner_id() << " := ";
@ -342,14 +354,55 @@ namespace euf {
else
out << "v ";
for (enode* arg : enode_args(n))
out << arg->get_owner_id() << " ";
out << std::setw(20) << " parents: ";
out << arg->get_owner_id() << " ";
for (unsigned i = n->num_args(); i < max_args; ++i)
out << " ";
out << "\t";
for (enode* p : enode_parents(n))
out << p->get_owner_id() << " ";
out << "\n";
}
return out;
}
void egraph::collect_statistics(statistics& st) const {
st.update("euf merge", m_stats.m_num_merge);
st.update("euf conflicts", m_stats.m_num_conflicts);
st.update("euf eq prop", m_stats.m_num_eqs);
st.update("euf lit prop", m_stats.m_num_lits);
}
void egraph::copy_from(egraph const& src, std::function<void*(void*)>& copy_justification) {
SASSERT(m_scopes.empty());
SASSERT(src.m_scopes.empty());
SASSERT(m_nodes.empty());
ptr_vector<enode> old_expr2new_enode, args;
ast_translation tr(src.m, m);
for (unsigned i = 0; i < src.m_nodes.size(); ++i) {
enode* n1 = src.m_nodes[i];
expr* e1 = src.m_exprs[i];
args.reset();
for (unsigned j = 0; j < n1->num_args(); ++j) {
args.push_back(old_expr2new_enode[n1->get_arg(j)->get_owner_id()]);
}
expr* e2 = tr(e1);
enode* n2 = mk(e2, args.size(), args.c_ptr());
m_exprs.push_back(e2);
m_nodes.push_back(n2);
old_expr2new_enode.setx(e1->get_id(), n2, nullptr);
}
for (unsigned i = 0; i < src.m_nodes.size(); ++i) {
enode* n1 = src.m_nodes[i];
enode* n1t = n1->m_target;
enode* n2 = m_nodes[i];
enode* n2t = n1t ? old_expr2new_enode[n1t->get_owner_id()] : nullptr;
SASSERT(!n1t || n2t);
if (n1t && n2->get_root() != n2t->get_root()) {
merge(n2, n2t, n1->m_justification.copy(copy_justification));
}
}
propagate();
}
}
template void euf::egraph::explain(ptr_vector<int>& justifications);

13
src/ast/euf/euf_egraph.h
View file

@ -24,6 +24,7 @@ Notes:
--*/
#pragma once
#include "util/statistics.h"
#include "ast/euf/euf_enode.h"
#include "ast/euf/euf_etable.h"
@ -43,6 +44,14 @@ namespace euf {
unsigned m_num_eqs;
unsigned m_num_nodes;
};
struct stats {
unsigned m_num_merge;
unsigned m_num_lits;
unsigned m_num_eqs;
unsigned m_num_conflicts;
stats() { reset(); }
void reset() { memset(this, 0, sizeof(*this)); }
};
ast_manager& m;
region m_region;
enode_vector m_worklist;
@ -60,6 +69,8 @@ namespace euf {
enode_vector m_new_eqs;
enode_vector m_new_lits;
enode_vector m_todo;
stats m_stats;
void push_eq(enode* r1, enode* n1, unsigned r2_num_parents) {
m_eqs.push_back(add_eq_record(r1, n1, r2_num_parents));
@ -120,7 +131,9 @@ namespace euf {
template <typename T>
void explain_eq(ptr_vector<T>& justifications, enode* a, enode* b, bool comm);
void invariant();
void copy_from(egraph const& src, std::function<void*(void*)>& copy_justification);
std::ostream& display(std::ostream& out) const;
void collect_statistics(statistics& st) const;
};
inline std::ostream& operator<<(std::ostream& out, egraph const& g) { return g.display(out); }

14
src/ast/euf/euf_justification.h
View file

@ -56,5 +56,19 @@ namespace euf {
bool is_commutative() const { return m_comm; }
template <typename T>
T* ext() const { SASSERT(is_external()); return static_cast<T*>(m_external); }
justification copy(std::function<void*(void*)>& copy_justification) const {
switch (m_kind) {
case external_t:
return external(copy_justification(m_external));
case axiom_t:
return axiom();
case congruence_t:
return congruence(m_comm);
default:
UNREACHABLE();
return axiom();
}
}
};
}

1
src/ast/pb_decl_plugin.h
View file

@ -94,6 +94,7 @@ public:
app * mk_ge(unsigned num_args, rational const * coeffs, expr * const * args, rational const& k);
app * mk_eq(unsigned num_args, rational const * coeffs, expr * const * args, rational const& k);
app * mk_lt(unsigned num_args, rational const * coeffs, expr * const * args, rational const& k);
bool is_pb(expr* t) const { return is_app(t) && to_app(t)->get_family_id() == get_family_id(); }
bool is_at_most_k(func_decl *a) const;
bool is_at_most_k(expr *a) const { return is_app(a) && is_at_most_k(to_app(a)->get_decl()); }
bool is_at_most_k(expr *a, rational& k) const;

1
src/sat/CMakeLists.txt
View file

@ -1,6 +1,5 @@
z3_add_component(sat
SOURCES
ba_solver.cpp
dimacs.cpp
sat_aig_cuts.cpp
sat_aig_finder.cpp

8
src/sat/ba/CMakeLists.txt Normal file
View file

@ -0,0 +1,8 @@
z3_add_component(sat_ba
SOURCES
ba_solver.cpp
ba_internalize.cpp
COMPONENT_DEPENDENCIES
sat
)

281
src/sat/ba/ba_internalize.cpp Normal file
View file

@ -0,0 +1,281 @@
/*++
Copyright (c) 2020 Microsoft Corporation
Module Name:
ba_internalize.h
Abstract:
INternalize methods for Boolean algebra operators.
Author:
Nikolaj Bjorner (nbjorner) 2020-08-25
--*/
#include "sat/ba/ba_internalize.h"
namespace sat {
literal ba_internalize::internalize(sat_internalizer& si, expr* e, bool sign, bool root) {
m_si = &si;
if (pb.is_pb(e))
return internalize_pb(e, sign, root);
if (m.is_xor(e))
return internalize_xor(e, sign, root);
UNREACHABLE();
return null_literal;
}
literal ba_internalize::internalize_xor(expr* e, bool sign, bool root) {
sat::literal_vector lits;
sat::bool_var v = m_solver.add_var(true);
lits.push_back(literal(v, true));
auto add_expr = [&](expr* a) {
literal lit = m_si->internalize(a);
m_solver.set_external(lit.var());
lits.push_back(lit);
};
expr* e1 = nullptr;
while (m.is_iff(e, e1, e))
add_expr(e1);
add_expr(e);
// ensure that = is converted to xor
for (unsigned i = 1; i + 1 < lits.size(); ++i) {
lits[i].neg();
}
ba.add_xr(lits);
auto* aig = m_solver.get_cut_simplifier();
if (aig) aig->add_xor(~lits.back(), lits.size() - 1, lits.c_ptr() + 1);
sat::literal lit(v, sign);
return literal(v, sign);
}
literal ba_internalize::internalize_pb(expr* e, bool sign, bool root) {
SASSERT(pb.is_pb(e));
app* t = to_app(e);
rational k = pb.get_k(t);
switch (t->get_decl_kind()) {
case OP_AT_MOST_K:
return convert_at_most_k(t, k, root, sign);
case OP_AT_LEAST_K:
return convert_at_least_k(t, k, root, sign);
case OP_PB_LE:
if (pb.has_unit_coefficients(t))
return convert_at_most_k(t, k, root, sign);
else
return convert_pb_le(t, root, sign);
case OP_PB_GE:
if (pb.has_unit_coefficients(t))
return convert_at_least_k(t, k, root, sign);
else
return convert_pb_ge(t, root, sign);
case OP_PB_EQ:
if (pb.has_unit_coefficients(t))
return convert_eq_k(t, k, root, sign);
else
return convert_pb_eq(t, root, sign);
default:
UNREACHABLE();
}
return null_literal;
}
void ba_internalize::check_unsigned(rational const& c) {
if (!c.is_unsigned()) {
throw default_exception("unsigned coefficient expected");
}
}
void ba_internalize::convert_to_wlits(app* t, sat::literal_vector const& lits, svector<wliteral>& wlits) {
for (unsigned i = 0; i < lits.size(); ++i) {
rational c = pb.get_coeff(t, i);
check_unsigned(c);
wlits.push_back(std::make_pair(c.get_unsigned(), lits[i]));
}
}
void ba_internalize::convert_pb_args(app* t, literal_vector& lits) {
for (expr* arg : *t) {
lits.push_back(m_si->internalize(arg));
m_solver.set_external(lits.back().var());
}
}
void ba_internalize::convert_pb_args(app* t, svector<wliteral>& wlits) {
sat::literal_vector lits;
convert_pb_args(t, lits);
convert_to_wlits(t, lits, wlits);
}
literal ba_internalize::convert_pb_le(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
k.neg();
svector<wliteral> wlits;
convert_pb_args(t, wlits);
for (wliteral& wl : wlits) {
wl.second.neg();
k += rational(wl.first);
}
check_unsigned(k);
if (root && m_solver.num_user_scopes() == 0) {
unsigned k1 = k.get_unsigned();
if (sign) {
k1 = 1 - k1;
for (wliteral& wl : wlits) {
wl.second.neg();
k1 += wl.first;
}
}
ba.add_pb_ge(null_bool_var, wlits, k1);
return null_literal;
}
else {
bool_var v = m_solver.add_var(true);
literal lit(v, sign);
ba.add_pb_ge(v, wlits, k.get_unsigned());
TRACE("ba", tout << "root: " << root << " lit: " << lit << "\n";);
return lit;
}
}
literal ba_internalize::convert_pb_ge(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
check_unsigned(k);
svector<wliteral> wlits;
convert_pb_args(t, wlits);
if (root && m_solver.num_user_scopes() == 0) {
unsigned k1 = k.get_unsigned();
if (sign) {
k1 = 1 - k1;
for (wliteral& wl : wlits) {
wl.second.neg();
k1 += wl.first;
}
}
ba.add_pb_ge(sat::null_bool_var, wlits, k1);
return null_literal;
}
else {
sat::bool_var v = m_solver.add_var(true);
sat::literal lit(v, sign);
ba.add_pb_ge(v, wlits, k.get_unsigned());
TRACE("goal2sat", tout << "root: " << root << " lit: " << lit << "\n";);
return lit;
}
}
literal ba_internalize::convert_pb_eq(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
SASSERT(k.is_unsigned());
svector<wliteral> wlits;
convert_pb_args(t, wlits);
bool base_assert = (root && !sign && m_solver.num_user_scopes() == 0);
bool_var v1 = base_assert ? null_bool_var : m_solver.add_var(true);
bool_var v2 = base_assert ? null_bool_var : m_solver.add_var(true);
ba.add_pb_ge(v1, wlits, k.get_unsigned());
k.neg();
for (wliteral& wl : wlits) {
wl.second.neg();
k += rational(wl.first);
}
check_unsigned(k);
ba.add_pb_ge(v2, wlits, k.get_unsigned());
if (base_assert) {
return null_literal;
}
else {
literal l1(v1, false), l2(v2, false);
bool_var v = m_solver.add_var(false);
literal l(v, false);
m_si->mk_clause(~l, l1);
m_si->mk_clause(~l, l2);
m_si->mk_clause(~l1, ~l2, l);
m_si->cache(t, l);
if (sign) l.neg();
return l;
}
}
literal ba_internalize::convert_at_least_k(app* t, rational const& k, bool root, bool sign) {
SASSERT(k.is_unsigned());
literal_vector lits;
convert_pb_args(t, lits);
unsigned k2 = k.get_unsigned();
if (root && m_solver.num_user_scopes() == 0) {
if (sign) {
for (literal& l : lits) l.neg();
k2 = lits.size() + 1 - k2;
}
ba.add_at_least(null_bool_var, lits, k2);
return null_literal;
}
else {
bool_var v = m_solver.add_var(true);
literal lit(v, false);
ba.add_at_least(v, lits, k.get_unsigned());
m_si->cache(t, lit);
if (sign) lit.neg();
TRACE("ba", tout << "root: " << root << " lit: " << lit << "\n";);
return lit;
}
}
literal ba_internalize::convert_at_most_k(app* t, rational const& k, bool root, bool sign) {
SASSERT(k.is_unsigned());
literal_vector lits;
convert_pb_args(t, lits);
for (literal& l : lits) {
l.neg();
}
unsigned k2 = lits.size() - k.get_unsigned();
if (root && m_solver.num_user_scopes() == 0) {
if (sign) {
for (literal& l : lits) l.neg();
k2 = lits.size() + 1 - k2;
}
ba.add_at_least(null_bool_var, lits, k2);
return null_literal;
}
else {
bool_var v = m_solver.add_var(true);
literal lit(v, false);
ba.add_at_least(v, lits, k2);
m_si->cache(t, lit);
if (sign) lit.neg();
return lit;
}
}
literal ba_internalize::convert_eq_k(app* t, rational const& k, bool root, bool sign) {
SASSERT(k.is_unsigned());
literal_vector lits;
convert_pb_args(t, lits);
bool_var v1 = (root && !sign) ? null_bool_var : m_solver.add_var(true);
bool_var v2 = (root && !sign) ? null_bool_var : m_solver.add_var(true);
ba.add_at_least(v1, lits, k.get_unsigned());
for (literal& l : lits) {
l.neg();
}
ba.add_at_least(v2, lits, lits.size() - k.get_unsigned());
if (!root || sign) {
literal l1(v1, false), l2(v2, false);
bool_var v = m_solver.add_var(false);
literal l(v, false);
m_si->mk_clause(~l, l1);
m_si->mk_clause(~l, l2);
m_si->mk_clause(~l1, ~l2, l);
m_si->cache(t, l);
if (sign) l.neg();
return l;
}
else {
return null_literal;
}
}
}

52
src/sat/ba/ba_internalize.h Normal file
View file

@ -0,0 +1,52 @@
/*++
Copyright (c) 2020 Microsoft Corporation
Module Name:
ba_internalize.h
Abstract:
INternalize methods for Boolean algebra operators.
Author:
Nikolaj Bjorner (nbjorner) 2020-08-25
--*/
#pragma once
#include "sat/smt/sat_smt.h"
#include "sat/ba/ba_solver.h"
#include "ast/pb_decl_plugin.h"
namespace sat {
class ba_internalize : public th_internalizer {
typedef std::pair<unsigned, literal> wliteral;
ast_manager& m;
pb_util pb;
ba_solver& ba;
solver_core& m_solver;
sat_internalizer* m_si;
literal convert_eq_k(app* t, rational const& k, bool root, bool sign);
literal convert_at_most_k(app* t, rational const& k, bool root, bool sign);
literal convert_at_least_k(app* t, rational const& k, bool root, bool sign);
literal convert_pb_eq(app* t, bool root, bool sign);
literal convert_pb_le(app* t, bool root, bool sign);
literal convert_pb_ge(app* t, bool root, bool sign);
void check_unsigned(rational const& c);
void convert_to_wlits(app* t, sat::literal_vector const& lits, svector<wliteral>& wlits);
void convert_pb_args(app* t, svector<wliteral>& wlits);
void convert_pb_args(app* t, literal_vector& lits);
literal internalize_pb(expr* e, bool sign, bool root);
literal internalize_xor(expr* e, bool sign, bool root);
public:
ba_internalize(ba_solver& ba, solver_core& s, ast_manager& m) : m(m), pb(m), ba(ba), m_solver(s) {}
literal internalize(sat_internalizer& si, expr* e, bool sign, bool root) override;
};
}

20
src/sat/ba_solver.cpp → src/sat/ba/ba_solver.cpp
View file

@ -18,7 +18,7 @@ Revision History:
--*/
#include <cmath>
#include "sat/ba_solver.h"
#include "sat/ba/ba_solver.h"
#include "sat/sat_types.h"
#include "util/mpz.h"
#include "sat/sat_simplifier_params.hpp"
@ -128,8 +128,8 @@ namespace sat {
// ----------------------
// card
ba_solver::card::card(unsigned id, literal lit, literal_vector const& lits, unsigned k):
pb_base(card_t, id, lit, lits.size(), get_obj_size(lits.size()), k) {
ba_solver::card::card(extension* e, unsigned id, literal lit, literal_vector const& lits, unsigned k):
pb_base(e, card_t, id, lit, lits.size(), get_obj_size(lits.size()), k) {
for (unsigned i = 0; i < size(); ++i) {
m_lits[i] = lits[i];
}
@ -155,8 +155,8 @@ namespace sat {
// -----------------------------------
// pb
ba_solver::pb::pb(unsigned id, literal lit, svector<ba_solver::wliteral> const& wlits, unsigned k):
pb_base(pb_t, id, lit, wlits.size(), get_obj_size(wlits.size()), k),
ba_solver::pb::pb(extension* e, unsigned id, literal lit, svector<ba_solver::wliteral> const& wlits, unsigned k):
pb_base(e, pb_t, id, lit, wlits.size(), get_obj_size(wlits.size()), k),
m_slack(0),
m_num_watch(0),
m_max_sum(0) {
@ -208,8 +208,8 @@ namespace sat {
// -----------------------------------
// xr
ba_solver::xr::xr(unsigned id, literal_vector const& lits):
constraint(xr_t, id, null_literal, lits.size(), get_obj_size(lits.size())) {
ba_solver::xr::xr(extension* e, unsigned id, literal_vector const& lits):
constraint(e, xr_t, id, null_literal, lits.size(), get_obj_size(lits.size())) {
for (unsigned i = 0; i < size(); ++i) {
m_lits[i] = lits[i];
}
@ -1897,7 +1897,7 @@ namespace sat {
return nullptr;
}
void * mem = m_allocator.allocate(card::get_obj_size(lits.size()));
card* c = new (mem) card(next_id(), lit, lits, k);
card* c = new (mem) card(this, next_id(), lit, lits, k);
c->set_learned(learned);
add_constraint(c);
return c;
@ -1966,7 +1966,7 @@ namespace sat {
return add_at_least(lit, lits, k, learned);
}
void * mem = m_allocator.allocate(pb::get_obj_size(wlits.size()));
pb* p = new (mem) pb(next_id(), lit, wlits, k);
pb* p = new (mem) pb(this, next_id(), lit, wlits, k);
p->set_learned(learned);
add_constraint(p);
return p;
@ -2082,7 +2082,7 @@ namespace sat {
break;
}
void * mem = m_allocator.allocate(xr::get_obj_size(lits.size()));
xr* x = new (mem) xr(next_id(), lits);
xr* x = new (mem) xr(this, next_id(), lits);
x->set_learned(learned);
add_constraint(x);
return x;

15
src/sat/ba_solver.h → src/sat/ba/ba_solver.h
View file

@ -24,6 +24,7 @@ Revision History:
#include "sat/sat_solver.h"
#include "sat/sat_lookahead.h"
#include "sat/sat_big.h"
#include "sat/smt/sat_smt.h"
#include "util/small_object_allocator.h"
#include "util/scoped_ptr_vector.h"
#include "util/sorting_network.h"
@ -64,7 +65,7 @@ namespace sat {
class xr;
class pb_base;
class constraint {
class constraint : public index_base {
protected:
tag_t m_tag;
bool m_removed;
@ -78,7 +79,8 @@ namespace sat {
unsigned m_id;
bool m_pure; // is the constraint pure (only positive occurrences)
public:
constraint(tag_t t, unsigned id, literal l, unsigned sz, size_t osz):
constraint(extension* e, tag_t t, unsigned id, literal l, unsigned sz, size_t osz):
index_base(e),
m_tag(t), m_removed(false), m_lit(l), m_watch(null_literal), m_glue(0), m_psm(0), m_size(sz), m_obj_size(osz), m_learned(false), m_id(id), m_pure(false) {}
ext_constraint_idx index() const { return reinterpret_cast<ext_constraint_idx>(this); }
unsigned id() const { return m_id; }
@ -132,7 +134,8 @@ namespace sat {
protected:
unsigned m_k;
public:
pb_base(tag_t t, unsigned id, literal l, unsigned sz, size_t osz, unsigned k): constraint(t, id, l, sz, osz), m_k(k) { VERIFY(k < 4000000000); }
pb_base(extension* e, tag_t t, unsigned id, literal l, unsigned sz, size_t osz, unsigned k):
constraint(e, t, id, l, sz, osz), m_k(k) { VERIFY(k < 4000000000); }
virtual void set_k(unsigned k) { VERIFY(k < 4000000000); m_k = k; }
virtual unsigned get_coeff(unsigned i) const { UNREACHABLE(); return 0; }
unsigned k() const { return m_k; }
@ -143,7 +146,7 @@ namespace sat {
literal m_lits[0];
public:
static size_t get_obj_size(unsigned num_lits) { return sizeof(card) + num_lits * sizeof(literal); }
card(unsigned id, literal lit, literal_vector const& lits, unsigned k);
card(extension* e, unsigned id, literal lit, literal_vector const& lits, unsigned k);
literal operator[](unsigned i) const { return m_lits[i]; }
literal& operator[](unsigned i) { return m_lits[i]; }
literal const* begin() const { return m_lits; }
@ -167,7 +170,7 @@ namespace sat {
wliteral m_wlits[0];
public:
static size_t get_obj_size(unsigned num_lits) { return sizeof(pb) + num_lits * sizeof(wliteral); }
pb(unsigned id, literal lit, svector<wliteral> const& wlits, unsigned k);
pb(extension* e, unsigned id, literal lit, svector<wliteral> const& wlits, unsigned k);
literal lit() const { return m_lit; }
wliteral operator[](unsigned i) const { return m_wlits[i]; }
wliteral& operator[](unsigned i) { return m_wlits[i]; }
@ -195,7 +198,7 @@ namespace sat {
literal m_lits[0];
public:
static size_t get_obj_size(unsigned num_lits) { return sizeof(xr) + num_lits * sizeof(literal); }
xr(unsigned id, literal_vector const& lits);
xr(extension* e, unsigned id, literal_vector const& lits);
literal operator[](unsigned i) const { return m_lits[i]; }
literal const* begin() const { return m_lits; }
literal const* end() const { return begin() + m_size; }

2
src/sat/euf/CMakeLists.txt
View file

@ -3,6 +3,6 @@ z3_add_component(sat_euf
euf_solver.cpp
COMPONENT_DEPENDENCIES
sat
sat_tactic
sat_smt
euf
)

318
src/sat/euf/euf_solver.cpp
View file

@ -14,28 +14,83 @@ Author:
Nikolaj Bjorner (nbjorner) 2020-08-25
--*/
#include "ast/pb_decl_plugin.h"
#include "sat/smt/sat_smt.h"
#include "sat/ba/ba_solver.h"
#include "sat/ba/ba_internalize.h"
#include "sat/euf/euf_solver.h"
#include "sat/sat_solver.h"
#include "tactic/tactic_exception.h"
namespace euf_sat {
namespace euf {
bool solver::propagate(literal l, ext_constraint_idx idx) {
UNREACHABLE();
return true;
/**
* retrieve extension that is associated with Boolean variable.
*/
sat::extension* solver::get_extension(sat::bool_var v) {
if (v >= m_var2node.size())
return nullptr;
euf::enode* n = m_var2node[v].first;
if (!n)
return nullptr;
return get_extension(n->get_owner());
}
void solver::get_antecedents(literal l, ext_justification_idx idx, literal_vector & r) {
void solver::add_extension(family_id fid, sat::extension* e) {
m_extensions.push_back(e);
m_id2extension.setx(fid, e, nullptr);
}
sat::extension* solver::get_extension(expr* e) {
if (is_app(e)) {
auto fid = to_app(e)->get_family_id();
if (fid == null_family_id)
return nullptr;
auto* ext = m_id2extension.get(fid, nullptr);
if (ext)
return ext;
pb_util pb(m);
if (pb.is_pb(e)) {
auto* ba = alloc(sat::ba_solver);
ba->set_solver(m_solver);
add_extension(pb.get_family_id(), ba);
auto* bai = alloc(sat::ba_internalize, *ba, s(), m);
m_id2internalize.setx(pb.get_family_id(), bai, nullptr);
m_internalizers.push_back(bai);
ba->push_scopes(s().num_scopes());
return ba;
}
}
return nullptr;
}
bool solver::propagate(literal l, ext_constraint_idx idx) {
auto* ext = sat::index_base::to_extension(idx);
SASSERT(ext != this);
return ext->propagate(l, idx);
}
void solver::get_antecedents(literal l, ext_justification_idx idx, literal_vector& r) {
auto* ext = sat::index_base::to_extension(idx);
if (ext == this)
get_antecedents(l, *euf_base::from_idx(idx), r);
else
ext->get_antecedents(l, idx, r);
}
void solver::get_antecedents(literal l, euf_base& j, literal_vector& r) {
m_explain.reset();
euf::enode* n = nullptr;
bool sign = false;
if (idx != 0) {
if (j.id() != 0) {
auto p = m_var2node[l.var()];
n = p.first;
SASSERT(n);
sign = l.sign() != p.second;
}
switch (idx) {
switch (j.id()) {
case 0:
SASSERT(m_egraph.inconsistent());
m_egraph.explain<unsigned>(m_explain);
@ -56,12 +111,20 @@ namespace euf_sat {
}
void solver::asserted(literal l) {
auto p = m_var2node[l.var()];
auto* ext = get_extension(l.var());
if (ext) {
ext->asserted(l);
return;
}
auto p = m_var2node.get(l.var(), enode_bool_pair(nullptr, false));
if (!p.first)
return;
bool sign = p.second != l.sign();
euf::enode* n = p.first;
expr* e = n->get_owner();
if (m.is_eq(e) && !sign) {
euf::enode* na = n->get_arg(0);
expr* e = n->get_owner();
if (m.is_eq(e) && !sign) {
euf::enode* na = n->get_arg(0);
euf::enode* nb = n->get_arg(1);
m_egraph.merge(na, nb, base_ptr() + l.index());
}
@ -69,16 +132,19 @@ namespace euf_sat {
euf::enode* nb = sign ? m_false : m_true;
m_egraph.merge(n, nb, base_ptr() + l.index());
}
// TBD: delay propagation?
propagate();
}
void solver::propagate() {
m_egraph.propagate();
if (m_egraph.inconsistent()) {
s().set_conflict(sat::justification::mk_ext_justification(s().scope_lvl(), 0));
s().set_conflict(sat::justification::mk_ext_justification(s().scope_lvl(), m_conflict_idx.to_index()));
return;
}
for (euf::enode* eq : m_egraph.new_eqs()) {
bool_var v = m_expr2var.to_bool_var(eq->get_owner());
s().assign(literal(v, false), sat::justification::mk_ext_justification(s().scope_lvl(), 1));
s().assign(literal(v, false), sat::justification::mk_ext_justification(s().scope_lvl(), m_eq_idx.to_index()));
}
for (euf::enode* p : m_egraph.new_lits()) {
expr* e = p->get_owner();
@ -86,73 +152,231 @@ namespace euf_sat {
SASSERT(m.is_bool(e));
SASSERT(m.is_true(p->get_root()->get_owner()) || sign);
bool_var v = m_expr2var.to_bool_var(e);
s().assign(literal(v, sign), sat::justification::mk_ext_justification(s().scope_lvl(), 2));
s().assign(literal(v, sign), sat::justification::mk_ext_justification(s().scope_lvl(), m_lit_idx.to_index()));
}
}
sat::check_result solver::check() {
bool give_up = false;
bool cont = false;
for (auto* e : m_extensions)
switch (e->check()) {
case sat::CR_CONTINUE: cont = true; break;
case sat::CR_GIVEUP: give_up = true; break;
default: break;
}
if (cont)
return sat::CR_CONTINUE;
if (give_up)
return sat::CR_GIVEUP;
return sat::CR_DONE;
}
void solver::push() {
for (auto* e : m_extensions)
e->push();
m_egraph.push();
++m_num_scopes;
}
void solver::pop(unsigned n) {
m_egraph.pop(n);
for (auto* e : m_extensions)
e->pop(n);
if (n <= m_num_scopes) {
m_num_scopes -= n;
return;
}
n -= m_num_scopes;
unsigned old_lim = m_bool_var_lim.size() - n;
unsigned old_sz = m_bool_var_lim[old_lim];
for (unsigned i = m_bool_var_trail.size(); i-- > old_sz; )
m_var2node[m_bool_var_trail[i]] = enode_bool_pair(nullptr, false);
m_bool_var_trail.shrink(old_sz);
m_bool_var_lim.shrink(old_lim);
}
void solver::pre_simplify() {}
void solver::simplify() {}
// have a way to replace l by r in all constraints
void solver::clauses_modifed() {}
lbool solver::get_phase(bool_var v) { return l_undef; }
void solver::pre_simplify() {
for (auto* e : m_extensions)
e->pre_simplify();
}
void solver::simplify() {
for (auto* e : m_extensions)
e->simplify();
}
void solver::clauses_modifed() {
for (auto* e : m_extensions)
e->clauses_modifed();
}
lbool solver::get_phase(bool_var v) {
auto* ext = get_extension(v);
if (ext)
return ext->get_phase(v);
return l_undef;
}
std::ostream& solver::display(std::ostream& out) const {
m_egraph.display(out);
for (auto* e : m_extensions)
e->display(out);
return out;
}
std::ostream& solver::display_justification(std::ostream& out, ext_justification_idx idx) const { return out; }
std::ostream& solver::display_constraint(std::ostream& out, ext_constraint_idx idx) const { return out; }
void solver::collect_statistics(statistics& st) const {}
sat::extension* solver::copy(sat::solver* s) { return nullptr; }
sat::extension* solver::copy(sat::lookahead* s, bool learned) { return nullptr; }
void solver::find_mutexes(literal_vector& lits, vector<literal_vector> & mutexes) {}
void solver::gc() {}
void solver::pop_reinit() {}
bool solver::validate() { return true; }
void solver::init_use_list(sat::ext_use_list& ul) {}
bool solver::is_blocked(literal l, ext_constraint_idx) { return false; }
bool solver::check_model(sat::model const& m) const { return true;}
unsigned solver::max_var(unsigned w) const { return w; }
std::ostream& solver::display_justification(std::ostream& out, ext_justification_idx idx) const {
auto* ext = sat::index_base::to_extension(idx);
if (ext != this)
return ext->display_justification(out, idx);
return out;
}
std::ostream& solver::display_constraint(std::ostream& out, ext_constraint_idx idx) const {
auto* ext = sat::index_base::to_extension(idx);
if (ext != this)
return ext->display_constraint(out, idx);
return out;
}
void solver::collect_statistics(statistics& st) const {
m_egraph.collect_statistics(st);
for (auto* e : m_extensions)
e->collect_statistics(st);
}
solver* solver::copy_core() {
ast_manager& to = m_translate ? m_translate->to() : m;
atom2bool_var& a2b = m_translate_expr2var ? *m_translate_expr2var : m_expr2var;
auto* r = alloc(solver, to, a2b);
std::function<void*(void*)> copy_justification = [&](void* x) { return (void*)(r->base_ptr() + ((unsigned*)x - base_ptr())); };
r->m_egraph.copy_from(m_egraph, copy_justification);
return r;
}
sat::extension* solver::copy(sat::solver* s) {
auto* r = copy_core();
r->set_solver(s);
for (auto* e : m_extensions)
r->m_extensions.push_back(e->copy(s));
return r;
}
sat::extension* solver::copy(sat::lookahead* s, bool learned) {
(void) learned;
auto* r = copy_core();
r->set_lookahead(s);
for (auto* e : m_extensions)
r->m_extensions.push_back(e->copy(s, learned));
return r;
}
void solver::find_mutexes(literal_vector& lits, vector<literal_vector> & mutexes) {
for (auto* e : m_extensions)
e->find_mutexes(lits, mutexes);
}
void solver::gc() {
for (auto* e : m_extensions)
e->gc();
}
void solver::pop_reinit() {
for (auto* e : m_extensions)
e->pop_reinit();
}
bool solver::validate() {
for (auto* e : m_extensions)
if (!e->validate())
return false;
return true;
}
void solver::init_use_list(sat::ext_use_list& ul) {
for (auto* e : m_extensions)
e->init_use_list(ul);
}
bool solver::is_blocked(literal l, ext_constraint_idx idx) {
auto* ext = sat::index_base::to_extension(idx);
if (ext != this)
return is_blocked(l, idx);
return false;
}
bool solver::check_model(sat::model const& m) const {
for (auto* e : m_extensions)
if (!e->check_model(m))
return false;
return true;
}
unsigned solver::max_var(unsigned w) const {
for (auto* e : m_extensions)
w = e->max_var(w);
for (unsigned sz = m_var2node.size(); sz-- > 0; ) {
euf::enode* n = m_var2node[sz].first;
if (n && m.is_bool(n->get_owner())) {
w = std::max(w, sz);
break;
}
}
return w;
}
sat::th_internalizer* solver::get_internalizer(expr* e) {
if (is_app(e))
return m_id2internalize.get(to_app(e)->get_family_id(), nullptr);
if (m.is_iff(e)) {
pb_util pb(m);
return m_id2internalize.get(pb.get_family_id(), nullptr);
}
return nullptr;
}
void solver::internalize(sat_internalizer& si, expr* e) {
sat::literal solver::internalize(sat::sat_internalizer& si, expr* e, bool sign, bool root) {
auto* ext = get_internalizer(e);
if (ext)
return ext->internalize(si, e, sign, root);
if (!m_true) {
m_true = visit(si, m.mk_true());
m_false = visit(si, m.mk_false());
}
SASSERT(!si.is_bool_op(e));
sat::scoped_stack _sc(m_stack);
unsigned sz = m_stack.size();
euf::enode* n = visit(si, e);
while (m_stack.size() > sz) {
loop:
if (!m.inc())
throw tactic_exception(m.limit().get_cancel_msg());
frame & fr = m_stack.back();
sat::frame & fr = m_stack.back();
expr* e = fr.m_e;
if (m_egraph.find(e)) {
m_stack.pop_back();
continue;
}
unsigned num = is_app(e) ? to_app(e)->get_num_args() : 0;
m_args.reset();
while (fr.m_idx < num) {
expr* arg = to_app(e)->get_arg(fr.m_idx);
fr.m_idx++;
n = visit(si, arg);
if (!n)
goto loop;
m_args.push_back(n);
}
m_args.reset();
for (unsigned i = 0; i < num; ++i)
m_args.push_back(m_egraph.find(to_app(e)->get_arg(i)));
n = m_egraph.mk(e, num, m_args.c_ptr());
attach_bool_var(si, n);
}
SASSERT(m_egraph.find(e));
return literal(m_expr2var.to_bool_var(e), sign);
}
euf::enode* solver::visit(sat_internalizer& si, expr* e) {
euf::enode* solver::visit(sat::sat_internalizer& si, expr* e) {
euf::enode* n = m_egraph.find(e);
if (n)
return n;
@ -160,11 +384,12 @@ namespace euf_sat {
sat::literal lit = si.internalize(e);
n = m_egraph.mk(e, 0, nullptr);
attach_bool_var(lit.var(), lit.sign(), n);
s().set_external(lit.var());
if (!m.is_true(e) && !m.is_false(e))
s().set_external(lit.var());
return n;
}
if (is_app(e) && to_app(e)->get_num_args() > 0) {
m_stack.push_back(frame(e));
m_stack.push_back(sat::frame(e));
return nullptr;
}
n = m_egraph.mk(e, 0, nullptr);
@ -172,7 +397,7 @@ namespace euf_sat {
return n;
}
void solver::attach_bool_var(sat_internalizer& si, euf::enode* n) {
void solver::attach_bool_var(sat::sat_internalizer& si, euf::enode* n) {
expr* e = n->get_owner();
if (m.is_bool(e)) {
sat::bool_var v = si.add_bool_var(e);
@ -181,8 +406,17 @@ namespace euf_sat {
}
void solver::attach_bool_var(sat::bool_var v, bool sign, euf::enode* n) {
m_var2node.reserve(v + 1);
m_var2node.reserve(v + 1, enode_bool_pair(nullptr, false));
for (; m_num_scopes > 0; --m_num_scopes)
m_bool_var_lim.push_back(m_bool_var_trail.size());
SASSERT(m_var2node[v].first == nullptr);
m_var2node[v] = euf::enode_bool_pair(n, sign);
m_bool_var_trail.push_back(v);
}
model_converter* solver::get_model() {
NOT_IMPLEMENTED_YET();
return nullptr;
}
}

70
src/sat/euf/euf_solver.h
View file

@ -16,53 +16,91 @@ Author:
--*/
#pragma once
#include "util/scoped_ptr_vector.h"
#include "sat/sat_extension.h"
#include "ast/euf/euf_egraph.h"
#include "sat/tactic/atom2bool_var.h"
#include "sat/tactic/goal2sat.h"
#include "ast/ast_translation.h"
#include "sat/smt/sat_smt.h"
#include "sat/smt/atom2bool_var.h"
#include "tactic/model_converter.h"
namespace euf_sat {
namespace euf {
typedef sat::literal literal;
typedef sat::ext_constraint_idx ext_constraint_idx;
typedef sat::ext_justification_idx ext_justification_idx;
typedef sat::literal_vector literal_vector;
typedef sat::bool_var bool_var;
struct frame {
expr* m_e;
unsigned m_idx;
frame(expr* e) : m_e(e), m_idx(0) {}
class euf_base : public sat::index_base {
unsigned m_id;
public:
euf_base(sat::extension* e, unsigned id) :
index_base(e), m_id(id)
{}
unsigned id() const { return m_id; }
static euf_base* from_idx(size_t z) { return reinterpret_cast<euf_base*>(z); }
};
class solver : public sat::extension {
class solver : public sat::extension, public sat::th_internalizer {
ast_manager& m;
atom2bool_var& m_expr2var;
euf::egraph m_egraph;
sat::solver* m_solver;
sat::lookahead* m_lookahead;
ast_translation* m_translate;
atom2bool_var* m_translate_expr2var;
euf::enode* m_true;
euf::enode* m_false;
svector<euf::enode_bool_pair> m_var2node;
ptr_vector<unsigned> m_explain;
euf::enode_vector m_args;
svector<frame> m_stack;
svector<sat::frame> m_stack;
unsigned m_num_scopes { 0 };
unsigned_vector m_bool_var_trail;
unsigned_vector m_bool_var_lim;
scoped_ptr_vector<sat::extension> m_extensions;
ptr_vector<sat::extension> m_id2extension;
ptr_vector<sat::th_internalizer> m_id2internalize;
scoped_ptr_vector<sat::th_internalizer> m_internalizers;
euf_base m_conflict_idx, m_eq_idx, m_lit_idx;
sat::solver& s() { return *m_solver; }
unsigned * base_ptr() { return reinterpret_cast<unsigned*>(this); }
euf::enode* visit(sat_internalizer& si, expr* e);
void attach_bool_var(sat_internalizer& si, euf::enode* n);
euf::enode* visit(sat::sat_internalizer& si, expr* e);
void attach_bool_var(sat::sat_internalizer& si, euf::enode* n);
void attach_bool_var(sat::bool_var v, bool sign, euf::enode* n);
solver* copy_core();
sat::extension* get_extension(sat::bool_var v);
void add_extension(family_id fid, sat::extension* e);
sat::th_internalizer* get_internalizer(expr* e);
void propagate();
void get_antecedents(literal l, euf_base& j, literal_vector& r);
public:
solver(ast_manager& m, atom2bool_var& expr2var):
m(m),
m_expr2var(expr2var),
m_egraph(m),
m_solver(nullptr)
m_solver(nullptr),
m_lookahead(nullptr),
m_translate(nullptr),
m_translate_expr2var(nullptr),
m_true(nullptr),
m_false(nullptr),
m_conflict_idx(this, 0),
m_eq_idx(this, 1),
m_lit_idx(this, 2)
{}
void set_solver(sat::solver* s) override { m_solver = s; }
void set_lookahead(sat::lookahead* s) override { }
void set_lookahead(sat::lookahead* s) override { m_lookahead = s; }
struct scoped_set_translate {
solver& s;
scoped_set_translate(solver& s, ast_translation& t, atom2bool_var& a2b):s(s) { s.m_translate = &t; s.m_translate_expr2var = &a2b; }
~scoped_set_translate() { s.m_translate = nullptr; s. m_translate_expr2var = nullptr; }
};
double get_reward(literal l, ext_constraint_idx idx, sat::literal_occs_fun& occs) const override { return 0; }
bool is_extended_binary(ext_justification_idx idx, literal_vector & r) override { return false; }
@ -92,7 +130,11 @@ namespace euf_sat {
bool check_model(sat::model const& m) const override;
unsigned max_var(unsigned w) const override;
void internalize(sat_internalizer& si, expr* e);
sat::literal internalize(sat::sat_internalizer& si, expr* e, bool sign, bool root) override;
model_converter* get_model();
sat::extension* get_extension(expr* e);
};
};

4
src/sat/sat_extension.h
View file

@ -47,8 +47,9 @@ namespace sat {
};
class extension {
public:
public:
virtual ~extension() {}
virtual unsigned get_id() const { return 0; }
virtual void set_solver(solver* s) = 0;
virtual void set_lookahead(lookahead* s) = 0;
virtual bool propagate(literal l, ext_constraint_idx idx) = 0;
@ -59,6 +60,7 @@ namespace sat {
virtual check_result check() = 0;
virtual lbool resolve_conflict() { return l_undef; } // stores result in sat::solver::m_lemma
virtual void push() = 0;
void push_scopes(unsigned n) { for (unsigned i = 0; i < n; ++i) push(); }
virtual void pop(unsigned n) = 0;
virtual void pre_simplify() = 0;
virtual void simplify() = 0;

7
src/sat/sat_local_search.cpp
View file

@ -19,7 +19,6 @@ Notes:
#include "sat/sat_local_search.h"
#include "sat/sat_solver.h"
#include "sat/ba_solver.h"
#include "sat/sat_params.hpp"
#include "util/timer.h"
@ -415,6 +414,10 @@ namespace sat {
}
m_num_non_binary_clauses = s.m_clauses.size();
if (s.get_extension())
throw default_exception("local search is incompatible with extensions");
#if 0
// copy cardinality clauses
ba_solver* ext = dynamic_cast<ba_solver*>(s.get_extension());
if (ext) {
@ -502,6 +505,8 @@ namespace sat {
}
}
}
#endif
if (_init) {
init();
}

1
src/sat/sat_params.pyg
View file

@ -57,6 +57,7 @@ def_module_params('sat',
('cardinality.encoding', SYMBOL, 'grouped', 'encoding used for at-most-k constraints: grouped, bimander, ordered, unate, circuit'),
('pb.resolve', SYMBOL, 'cardinality', 'resolution strategy for boolean algebra solver: cardinality, rounding'),
('pb.lemma_format', SYMBOL, 'cardinality', 'generate either cardinality or pb lemmas'),
('euf', BOOL, False, 'enable euf solver'),
('ddfw_search', BOOL, False, 'use ddfw local search instead of CDCL'),
('ddfw.init_clause_weight', UINT, 8, 'initial clause weight for DDFW local search'),
('ddfw.use_reward_pct', UINT, 15, 'percentage to pick highest reward variable when it has reward 0'),

1
src/sat/sat_solver.h
View file

@ -635,6 +635,7 @@ namespace sat {
void user_pop(unsigned num_scopes) override;
void pop_to_base_level() override;
unsigned num_user_scopes() const override { return m_user_scope_literals.size(); }
unsigned num_scopes() const override { return m_scopes.size(); }
reslimit& rlimit() { return m_rlimit; }
params_ref const& params() { return m_params; }
// -----------------------

2
src/sat/sat_solver_core.h
View file

@ -86,6 +86,8 @@ namespace sat {
virtual void user_push() { throw default_exception("optional API not supported"); }
virtual void user_pop(unsigned num_scopes) {};
virtual unsigned num_user_scopes() const { return 0;}
virtual unsigned num_scopes() const { return 0; }
// hooks for extension solver. really just ba_solver atm.
virtual extension* get_extension() const { return nullptr; }

8
src/sat/smt/CMakeLists.txt Normal file
View file

@ -0,0 +1,8 @@
z3_add_component(sat_smt
SOURCES
atom2bool_var.cpp
COMPONENT_DEPENDENCIES
sat
ast
)

2
src/sat/tactic/atom2bool_var.cpp → src/sat/smt/atom2bool_var.cpp
View file

@ -20,7 +20,7 @@ Notes:
#include "util/ref_util.h"
#include "ast/ast_smt2_pp.h"
#include "tactic/goal.h"
#include "sat/tactic/atom2bool_var.h"
#include "sat/smt/atom2bool_var.h"
void atom2bool_var::mk_inv(expr_ref_vector & lit2expr) const {
for (auto const& kv : m_mapping) {

0
src/sat/tactic/atom2bool_var.h → src/sat/smt/atom2bool_var.h
View file

62
src/sat/smt/sat_smt.h Normal file
View file

@ -0,0 +1,62 @@
/*++
Copyright (c) 2020 Microsoft Corporation
Module Name:
sat_smt.h
Abstract:
Header for SMT theories over SAT solver
Author:
Nikolaj Bjorner (nbjorner) 2020-08-25
--*/
#pragma once
#pragma once
#include "sat/sat_solver.h"
#include "ast/ast.h"
namespace sat {
struct frame {
expr* m_e;
unsigned m_idx;
frame(expr* e) : m_e(e), m_idx(0) {}
};
struct scoped_stack {
svector<frame>& s;
unsigned sz;
scoped_stack(svector<frame>& s):s(s), sz(s.size()) {}
~scoped_stack() { s.shrink(sz); }
};
class sat_internalizer {
public:
virtual bool is_bool_op(expr* e) const = 0;
virtual sat::literal internalize(expr* e) = 0;
virtual sat::bool_var add_bool_var(expr* e) = 0;
virtual void mk_clause(literal a, literal b) = 0;
virtual void mk_clause(literal l1, literal l2, literal l3, bool is_lemma = false) = 0;
virtual void cache(app* t, literal l) = 0;
};
class th_internalizer {
public:
virtual literal internalize(sat_internalizer& si, expr* e, bool sign, bool root) = 0;
};
class index_base {
extension* ex;
public:
index_base(extension* e): ex(e) {}
static extension* to_extension(size_t s) { return from_index(s)->ex; }
static index_base* from_index(size_t s) { return reinterpret_cast<index_base*>(s); }
size_t to_index() const { return reinterpret_cast<size_t>(this); }
};
}

5
src/sat/tactic/CMakeLists.txt
View file

@ -1,13 +1,14 @@
z3_add_component(sat_tactic
SOURCES
atom2bool_var.cpp
goal2sat.cpp
sat_tactic.cpp
COMPONENT_DEPENDENCIES
sat
tactic
solver
euf
sat_smt
sat_ba
sat_euf
TACTIC_HEADERS
sat_tactic.h
)

449
src/sat/tactic/goal2sat.cpp
View file

@ -34,15 +34,17 @@ Notes:
#include "ast/ast_util.h"
#include "ast/for_each_expr.h"
#include "sat/tactic/goal2sat.h"
#include "sat/ba_solver.h"
#include "sat/sat_cut_simplifier.h"
#include "sat/ba/ba_internalize.h"
#include "sat/ba/ba_solver.h"
#include "sat/euf/euf_solver.h"
#include "model/model_evaluator.h"
#include "model/model_v2_pp.h"
#include "tactic/tactic.h"
#include "tactic/generic_model_converter.h"
#include<sstream>
struct goal2sat::imp : public sat_internalizer {
struct goal2sat::imp : public sat::sat_internalizer {
struct frame {
app * m_t;
unsigned m_root:1;
@ -53,7 +55,6 @@ struct goal2sat::imp : public sat_internalizer {
};
ast_manager & m;
pb_util pb;
sat::ba_solver* m_ext;
sat::cut_simplifier* m_aig;
svector<frame> m_frame_stack;
svector<sat::literal> m_result_stack;
@ -69,12 +70,13 @@ struct goal2sat::imp : public sat_internalizer {
expr_ref_vector m_interpreted_atoms;
bool m_default_external;
bool m_xor_solver;
bool m_euf;
bool m_is_lemma;
imp(ast_manager & _m, params_ref const & p, sat::solver_core & s, atom2bool_var & map, dep2asm_map& dep2asm, bool default_external):
m(_m),
pb(m),
m_ext(nullptr),
m_aig(nullptr),
m_solver(s),
m_map(map),
@ -92,7 +94,7 @@ struct goal2sat::imp : public sat_internalizer {
m_ite_extra = p.get_bool("ite_extra", true);
m_max_memory = megabytes_to_bytes(p.get_uint("max_memory", UINT_MAX));
m_xor_solver = p.get_bool("xor_solver", false);
if (m_xor_solver) ensure_extension();
m_euf = false;
}
void throw_op_not_handled(std::string const& s) {
@ -107,12 +109,12 @@ struct goal2sat::imp : public sat_internalizer {
void set_lemma_mode(bool f) { m_is_lemma = f; }
void mk_clause(sat::literal l1, sat::literal l2) {
void mk_clause(sat::literal l1, sat::literal l2) override {
TRACE("goal2sat", tout << "mk_clause: " << l1 << " " << l2 << "\n";);
m_solver.add_clause(l1, l2, m_is_lemma);
}
void mk_clause(sat::literal l1, sat::literal l2, sat::literal l3, bool is_lemma = false) {
void mk_clause(sat::literal l1, sat::literal l2, sat::literal l3, bool is_lemma = false) override {
TRACE("goal2sat", tout << "mk_clause: " << l1 << " " << l2 << " " << l3 << "\n";);
m_solver.add_clause(l1, l2, l3, m_is_lemma || is_lemma);
}
@ -143,6 +145,10 @@ struct goal2sat::imp : public sat_internalizer {
return v;
}
void cache(app* t, sat::literal l) override {
m_cache.insert(t, l);
}
void convert_atom(expr * t, bool root, bool sign) {
SASSERT(m.is_bool(t));
sat::literal l;
@ -166,7 +172,12 @@ struct goal2sat::imp : public sat_internalizer {
l = sat::literal(v, sign);
TRACE("sat", tout << "new_var: " << v << ": " << mk_bounded_pp(t, m, 2) << " " << is_uninterp_const(t) << "\n";);
if (!is_uninterp_const(t)) {
m_interpreted_atoms.push_back(t);
if (m_euf) {
convert_euf(t, root, sign);
return;
}
else
m_interpreted_atoms.push_back(t);
}
}
}
@ -183,8 +194,7 @@ struct goal2sat::imp : public sat_internalizer {
}
bool convert_app(app* t, bool root, bool sign) {
if (t->get_family_id() == pb.get_family_id()) {
ensure_extension();
if (pb.is_pb(t)) {
m_frame_stack.push_back(frame(to_app(t), root, sign, 0));
return false;
}
@ -208,7 +218,6 @@ struct goal2sat::imp : public sat_internalizer {
return false;
}
bool visit(expr * t, bool root, bool sign) {
if (!is_app(t)) {
convert_atom(t, root, sign);
@ -216,9 +225,8 @@ struct goal2sat::imp : public sat_internalizer {
}
if (process_cached(to_app(t), root, sign))
return true;
if (to_app(t)->get_family_id() != m.get_basic_family_id()) {
return convert_app(to_app(t), root, sign);
}
if (to_app(t)->get_family_id() != m.get_basic_family_id())
return convert_app(to_app(t), root, sign);
switch (to_app(t)->get_decl_kind()) {
case OP_NOT:
case OP_OR:
@ -341,11 +349,11 @@ struct goal2sat::imp : public sat_internalizer {
mk_clause(num+1, lits);
if (m_aig) {
m_aig->add_and(l, num, aig_lits.c_ptr());
}
unsigned old_sz = m_result_stack.size() - num - 1;
m_result_stack.shrink(old_sz);
}
if (sign)
l.neg();
unsigned old_sz = m_result_stack.size() - num - 1;
m_result_stack.shrink(old_sz);
m_result_stack.push_back(l);
TRACE("goal2sat", tout << m_result_stack << "\n";);
}
@ -382,9 +390,9 @@ struct goal2sat::imp : public sat_internalizer {
mk_clause(t, e, ~l, false);
}
if (m_aig) m_aig->add_ite(l, c, t, e);
m_result_stack.shrink(sz-3);
if (sign)
l.neg();
m_result_stack.shrink(sz-3);
m_result_stack.push_back(l);
}
}
@ -415,268 +423,70 @@ struct goal2sat::imp : public sat_internalizer {
mk_clause(~l, ~l1, l2);
mk_clause(l, l1, l2);
mk_clause(l, ~l1, ~l2);
if (m_aig) m_aig->add_iff(l, l1, l2);
m_result_stack.shrink(sz-2);
if (m_aig) m_aig->add_iff(l, l1, l2);
if (sign)
l.neg();
m_result_stack.shrink(sz - 2);
m_result_stack.push_back(l);
}
}
void convert_iff(app * t, bool root, bool sign) {
TRACE("goal2sat", tout << "convert_iff " << root << " " << sign << "\n" << mk_bounded_pp(t, m, 2) << "\n";);
unsigned sz = m_result_stack.size();
unsigned num = get_num_args(t);
SASSERT(sz >= num && num >= 2);
if (num == 2) {
if (is_xor(t))
convert_ba(t, root, sign);
else
convert_iff2(t, root, sign);
}
void convert_euf(expr* e, bool root, bool sign) {
sat::extension* ext = m_solver.get_extension();
euf::solver* euf = nullptr;
if (!ext) {
euf = alloc(euf::solver, m, m_map);
m_solver.set_extension(euf);
for (unsigned i = m_solver.num_scopes(); i-- > 0; )
euf->push();
}
else {
euf = dynamic_cast<euf::solver*>(ext);
}
if (!euf)
throw default_exception("cannot convert to euf");
sat::literal lit = euf->internalize(*this, e, sign, root);
if (root)
m_result_stack.reset();
if (lit == sat::null_literal)
return;
}
sat::literal_vector lits;
sat::bool_var v = m_solver.add_var(true);
lits.push_back(sat::literal(v, true));
convert_pb_args(num, lits);
// ensure that = is converted to xor
for (unsigned i = 1; i + 1 < lits.size(); ++i) {
lits[i].neg();
}
ensure_extension();
m_ext->add_xr(lits);
if (m_aig) m_aig->add_xor(~lits.back(), lits.size() - 1, lits.c_ptr() + 1);
sat::literal lit(v, sign);
if (root) {
m_result_stack.reset();
if (root)
mk_clause(lit);
}
else {
m_result_stack.shrink(sz - num);
else
m_result_stack.push_back(lit);
}
}
void convert_pb_args(unsigned num_args, sat::literal_vector& lits) {
unsigned sz = m_result_stack.size();
for (unsigned i = 0; i < num_args; ++i) {
sat::literal lit(m_result_stack[sz - num_args + i]);
if (!m_solver.is_external(lit.var())) {
m_solver.set_external(lit.var());
}
lits.push_back(lit);
}
}
typedef std::pair<unsigned, sat::literal> wliteral;
void check_unsigned(rational const& c) {
if (!c.is_unsigned()) {
throw default_exception("unsigned coefficient expected");
}
}
void convert_to_wlits(app* t, sat::literal_vector const& lits, svector<wliteral>& wlits) {
for (unsigned i = 0; i < lits.size(); ++i) {
rational c = pb.get_coeff(t, i);
check_unsigned(c);
wlits.push_back(std::make_pair(c.get_unsigned(), lits[i]));
}
}
void convert_pb_args(app* t, svector<wliteral>& wlits) {
sat::literal_vector lits;
convert_pb_args(t->get_num_args(), lits);
convert_to_wlits(t, lits, wlits);
}
void push_result(bool root, sat::literal lit, unsigned num_args) {
if (root) {
m_result_stack.reset();
mk_clause(lit);
void convert_ba(app* t, bool root, bool sign) {
sat::extension* ext = m_solver.get_extension();
sat::ba_solver* ba = nullptr;
if (!ext) {
ba = alloc(sat::ba_solver);
m_solver.set_extension(ba);
ba->push_scopes(m_solver.num_scopes());
}
else {
m_result_stack.shrink(m_result_stack.size() - num_args);
m_result_stack.push_back(lit);
ba = dynamic_cast<sat::ba_solver*>(ext);
}
}
void convert_pb_ge(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
check_unsigned(k);
svector<wliteral> wlits;
convert_pb_args(t, wlits);
if (root && m_solver.num_user_scopes() == 0) {
if (!ba)
throw default_exception("cannot convert to pb");
sat::ba_internalize internalize(*ba, m_solver, m);
sat::literal lit = internalize.internalize(*this, t, sign, root);
if (root)
m_result_stack.reset();
unsigned k1 = k.get_unsigned();
if (sign) {
k1 = 1 - k1;
for (wliteral& wl : wlits) {
wl.second.neg();
k1 += wl.first;
}
}
m_ext->add_pb_ge(sat::null_bool_var, wlits, k1);
}
else {
sat::bool_var v = m_solver.add_var(true);
sat::literal lit(v, sign);
m_ext->add_pb_ge(v, wlits, k.get_unsigned());
TRACE("goal2sat", tout << "root: " << root << " lit: " << lit << "\n";);
push_result(root, lit, t->get_num_args());
}
}
void convert_pb_le(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
k.neg();
svector<wliteral> wlits;
convert_pb_args(t, wlits);
for (wliteral& wl : wlits) {
wl.second.neg();
k += rational(wl.first);
}
check_unsigned(k);
if (root && m_solver.num_user_scopes() == 0) {
m_result_stack.reset();
unsigned k1 = k.get_unsigned();
if (sign) {
k1 = 1 - k1;
for (wliteral& wl : wlits) {
wl.second.neg();
k1 += wl.first;
}
}
m_ext->add_pb_ge(sat::null_bool_var, wlits, k1);
}
else {
sat::bool_var v = m_solver.add_var(true);
sat::literal lit(v, sign);
m_ext->add_pb_ge(v, wlits, k.get_unsigned());
TRACE("goal2sat", tout << "root: " << root << " lit: " << lit << "\n";);
push_result(root, lit, t->get_num_args());
}
}
void convert_pb_eq(app* t, bool root, bool sign) {
rational k = pb.get_k(t);
SASSERT(k.is_unsigned());
svector<wliteral> wlits;
convert_pb_args(t, wlits);
bool base_assert = (root && !sign && m_solver.num_user_scopes() == 0);
sat::bool_var v1 = base_assert ? sat::null_bool_var : m_solver.add_var(true);
sat::bool_var v2 = base_assert ? sat::null_bool_var : m_solver.add_var(true);
m_ext->add_pb_ge(v1, wlits, k.get_unsigned());
k.neg();
for (wliteral& wl : wlits) {
wl.second.neg();
k += rational(wl.first);
}
check_unsigned(k);
m_ext->add_pb_ge(v2, wlits, k.get_unsigned());
if (base_assert) {
m_result_stack.reset();
}
else {
sat::literal l1(v1, false), l2(v2, false);
sat::bool_var v = m_solver.add_var(false);
sat::literal l(v, false);
mk_clause(~l, l1);
mk_clause(~l, l2);
mk_clause(~l1, ~l2, l);
m_cache.insert(t, l);
if (sign) l.neg();
push_result(root, l, t->get_num_args());
}
}
void convert_at_least_k(app* t, rational const& k, bool root, bool sign) {
SASSERT(k.is_unsigned());
sat::literal_vector lits;
convert_pb_args(t->get_num_args(), lits);
unsigned k2 = k.get_unsigned();
if (root && m_solver.num_user_scopes() == 0) {
m_result_stack.reset();
if (sign) {
for (sat::literal& l : lits) l.neg();
k2 = lits.size() + 1 - k2;
}
m_ext->add_at_least(sat::null_bool_var, lits, k2);
}
else {
sat::bool_var v = m_solver.add_var(true);
sat::literal lit(v, false);
m_ext->add_at_least(v, lits, k.get_unsigned());
m_cache.insert(t, lit);
if (sign) lit.neg();
TRACE("goal2sat", tout << "root: " << root << " lit: " << lit << "\n";);
push_result(root, lit, t->get_num_args());
}
}
void convert_at_most_k(app* t, rational const& k, bool root, bool sign) {
SASSERT(k.is_unsigned());
sat::literal_vector lits;
convert_pb_args(t->get_num_args(), lits);
for (sat::literal& l : lits) {
l.neg();
}
unsigned k2 = lits.size() - k.get_unsigned();
if (root && m_solver.num_user_scopes() == 0) {
m_result_stack.reset();
if (sign) {
for (sat::literal& l : lits) l.neg();
k2 = lits.size() + 1 - k2;
}
m_ext->add_at_least(sat::null_bool_var, lits, k2);
}
else {
sat::bool_var v = m_solver.add_var(true);
sat::literal lit(v, false);
m_ext->add_at_least(v, lits, k2);
m_cache.insert(t, lit);
if (sign) lit.neg();
push_result(root, lit, t->get_num_args());
}
}
void convert_eq_k(app* t, rational const& k, bool root, bool sign) {
SASSERT(k.is_unsigned());
sat::literal_vector lits;
convert_pb_args(t->get_num_args(), lits);
sat::bool_var v1 = (root && !sign) ? sat::null_bool_var : m_solver.add_var(true);
sat::bool_var v2 = (root && !sign) ? sat::null_bool_var : m_solver.add_var(true);
m_ext->add_at_least(v1, lits, k.get_unsigned());
for (sat::literal& l : lits) {
l.neg();
}
m_ext->add_at_least(v2, lits, lits.size() - k.get_unsigned());
if (root && !sign) {
m_result_stack.reset();
}
else {
sat::literal l1(v1, false), l2(v2, false);
sat::bool_var v = m_solver.add_var(false);
sat::literal l(v, false);
mk_clause(~l, l1);
mk_clause(~l, l2);
mk_clause(~l1, ~l2, l);
m_cache.insert(t, l);
if (sign) l.neg();
push_result(root, l, t->get_num_args());
}
}
void ensure_extension() {
if (!m_ext) {
sat::extension* ext = m_solver.get_extension();
if (ext) {
m_ext = dynamic_cast<sat::ba_solver*>(ext);
SASSERT(m_ext);
}
if (!m_ext) {
m_ext = alloc(sat::ba_solver);
m_solver.set_extension(m_ext);
}
}
if (lit == sat::null_literal)
return;
if (root)
mk_clause(lit);
else
m_result_stack.push_back(lit);
}
void convert(app * t, bool root, bool sign) {
@ -698,95 +508,45 @@ struct goal2sat::imp : public sat_internalizer {
UNREACHABLE();
}
}
else if (t->get_family_id() == pb.get_family_id()) {
ensure_extension();
rational k;
switch (t->get_decl_kind()) {
case OP_AT_MOST_K:
k = pb.get_k(t);
convert_at_most_k(t, k, root, sign);
break;
case OP_AT_LEAST_K:
k = pb.get_k(t);
convert_at_least_k(t, k, root, sign);
break;
case OP_PB_LE:
if (pb.has_unit_coefficients(t)) {
k = pb.get_k(t);
convert_at_most_k(t, k, root, sign);
}
else {
convert_pb_le(t, root, sign);
}
break;
case OP_PB_GE:
if (pb.has_unit_coefficients(t)) {
k = pb.get_k(t);
convert_at_least_k(t, k, root, sign);
}
else {
convert_pb_ge(t, root, sign);
}
break;
case OP_PB_EQ:
if (pb.has_unit_coefficients(t)) {
k = pb.get_k(t);
convert_eq_k(t, k, root, sign);
}
else {
convert_pb_eq(t, root, sign);
}
break;
default:
UNREACHABLE();
}
else if (pb.is_pb(t)) {
convert_ba(t, root, sign);
}
else {
UNREACHABLE();
}
}
unsigned get_num_args(app* t) {
if (m.is_iff(t) && m_xor_solver) {
unsigned n = 2;
while (m.is_iff(t->get_arg(1))) {
++n;
t = to_app(t->get_arg(1));
}
return n;
}
else {
return t->get_num_args();
}
bool is_xor(app* t) const {
return m_xor_solver && m.is_iff(t) && m.is_iff(t->get_arg(1));
}
expr* get_arg(app* t, unsigned idx) {
if (m.is_iff(t) && m_xor_solver) {
while (idx >= 1) {
SASSERT(m.is_iff(t));
t = to_app(t->get_arg(1));
--idx;
}
if (m.is_iff(t)) {
return t->get_arg(idx);
}
else {
return t;
struct scoped_stack {
sat::literal_vector& r;
unsigned rsz;
svector<frame>& frames;
unsigned fsz;
bool is_root;
scoped_stack(imp& x, bool is_root) :
r(x.m_result_stack), rsz(r.size()), frames(x.m_frame_stack), fsz(frames.size()), is_root(is_root)
{}
~scoped_stack() {
if (frames.size() > fsz) {
frames.shrink(fsz);
r.shrink(rsz);
return;
}
SASSERT(frames.size() == fsz);
SASSERT(!is_root || rsz == r.size());
SASSERT(is_root || rsz + 1 == r.size());
}
else {
return t->get_arg(idx);
}
}
};
void process(expr* n, bool is_root) {
scoped_stack _sc(*this, is_root);
unsigned sz = m_frame_stack.size();
if (visit(n, is_root, false)) {
SASSERT(m_result_stack.empty());
if (visit(n, is_root, false))
return;
}
while (m_frame_stack.size() > sz) {
loop:
if (!m.inc())
@ -809,9 +569,14 @@ struct goal2sat::imp : public sat_internalizer {
visit(t->get_arg(0), root, !sign);
continue;
}
unsigned num = get_num_args(t);
if (is_xor(t)) {
convert_ba(t, root, sign);
m_frame_stack.pop_back();
continue;
}
unsigned num = t->get_num_args();
while (fr.m_idx < num) {
expr * arg = get_arg(t, fr.m_idx);
expr * arg = t->get_arg(fr.m_idx);
fr.m_idx++;
if (!visit(arg, false, false))
goto loop;
@ -825,11 +590,11 @@ struct goal2sat::imp : public sat_internalizer {
}
sat::literal internalize(expr* n) override {
SASSERT(m_result_stack.empty());
unsigned sz = m_result_stack.size();
process(n, false);
SASSERT(m_result_stack.size() == 1);
SASSERT(m_result_stack.size() == sz + 1);
sat::literal result = m_result_stack.back();
m_result_stack.reset();
m_result_stack.pop_back();
return result;
}

12
src/sat/tactic/goal2sat.h
View file

@ -32,15 +32,8 @@ Notes:
#include "sat/sat_solver.h"
#include "tactic/model_converter.h"
#include "tactic/generic_model_converter.h"
#include "sat/tactic/atom2bool_var.h"
class sat_internalizer {
public:
virtual bool is_bool_op(expr* e) const = 0;
virtual sat::literal internalize(expr* e) = 0;
virtual sat::bool_var add_bool_var(expr* e) = 0;
};
#include "sat/smt/atom2bool_var.h"
#include "sat/smt/sat_smt.h"
class goal2sat {
struct imp;
@ -58,7 +51,6 @@ public:
static bool has_unsupported_bool(goal const & s);
/**
\brief "Compile" the goal into the given sat solver.
Store a mapping from atoms to boolean variables into m.

2
src/shell/dimacs_frontend.cpp
View file

@ -25,7 +25,7 @@ Revision History:
#include "sat/dimacs.h"
#include "sat/sat_params.hpp"
#include "sat/sat_solver.h"
#include "sat/ba_solver.h"
#include "sat/ba/ba_solver.h"
#include "sat/tactic/goal2sat.h"
#include "ast/reg_decl_plugins.h"
#include "tactic/tactic.h"