mirrors/z3
3
0
Fork 0
mirror of https://github.com/Z3Prover/z3 synced 2025-12-04 19:16:46 +00:00
Code Activity

restart projection when found a non-trivial nullified polynomial, and remove is_square_free

Browse source 
Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2025-11-22 06:08:32 -10:00
parent 82f0cfb7cc
commit ac58f53703
2 changed files with 92 additions and 87 deletions
Download patch file Download diff file Expand all files Collapse all files

177
src/nlsat/nlsat_explain.cpp
View file

@ -25,6 +25,8 @@ Revision History:
namespace nlsat { namespace nlsat {
struct add_all_coeffs_restart {};
typedef polynomial::polynomial_ref_vector polynomial_ref_vector; typedef polynomial::polynomial_ref_vector polynomial_ref_vector;
typedef ref_buffer<poly, pmanager> polynomial_ref_buffer; typedef ref_buffer<poly, pmanager> polynomial_ref_buffer;
@ -463,8 +465,12 @@ namespace nlsat {
// and were added as assumptions. // and were added as assumptions.
p = m_pm.mk_zero(); p = m_pm.mk_zero();
TRACE(nlsat_explain, tout << "all coefficients of p vanished\n";); TRACE(nlsat_explain, tout << "all coefficients of p vanished\n";);
VERIFY(m_add_all_coeffs); // need to fall back to Collins projection otherwise if (m_add_all_coeffs) {
return; return;
}
TRACE(nlsat_explain, tout << "falling back to add-all-coeffs projection\n";);
m_add_all_coeffs = true;
throw add_all_coeffs_restart();
} }
k--; k--;
p = reduct; p = reduct;
@ -716,35 +722,6 @@ namespace nlsat {
} }
} }
// The monomials have to be square free according to
//"An improved projection operation for cylindrical algebraic decomposition of three-dimensional space", by McCallum, Scott
bool is_square_free(polynomial_ref_vector &ps, var x) {
if (m_add_all_coeffs)
return false;
polynomial_ref p(m_pm);
polynomial_ref lc_poly(m_pm);
polynomial_ref disc_poly(m_pm);
for (unsigned i = 0; i < ps.size(); i++) {
p = ps.get(i);
unsigned k_deg = m_pm.degree(p, x);
if (k_deg == 0)
continue;
// p depends on x
disc_poly = discriminant(p, x); // Use global helper
if (sign(disc_poly) == 0) { // Discriminant is zero
TRACE(nlsat_explain, tout << "p is not square free:\n ";
display(tout, p); tout << "\ndiscriminant: "; display(tout, disc_poly) << "\n";
m_solver.display_assignment(tout) << '\n';
m_solver.display_var(tout << "x:", x) << '\n';
);
return false;
}
}
return true;
}
// If each p from ps is square-free then add the leading coefficents to the projection. // If each p from ps is square-free then add the leading coefficents to the projection.
// Otherwise, add each coefficient of each p to the projection. // Otherwise, add each coefficient of each p to the projection.
@ -752,7 +729,6 @@ namespace nlsat {
polynomial_ref p(m_pm); polynomial_ref p(m_pm);
polynomial_ref coeff(m_pm); polynomial_ref coeff(m_pm);
bool only_lc = !m_add_all_coeffs && is_square_free(ps, x);
// Add the leading or all coeffs, depening on being square-free // Add the leading or all coeffs, depening on being square-free
for (unsigned i = 0; i < ps.size(); i++) { for (unsigned i = 0; i < ps.size(); i++) {
p = ps.get(i); p = ps.get(i);
@ -764,7 +740,7 @@ namespace nlsat {
coeff = m_pm.coeff(p, x, j_coeff_deg); coeff = m_pm.coeff(p, x, j_coeff_deg);
TRACE(nlsat_explain, tout << " coeff deg " << j_coeff_deg << ": "; display(tout, coeff) << "\n";); TRACE(nlsat_explain, tout << " coeff deg " << j_coeff_deg << ": "; display(tout, coeff) << "\n";);
insert_fresh_factors_in_todo(coeff); insert_fresh_factors_in_todo(coeff);
if (only_lc) if (!m_add_all_coeffs)
break; break;
} }
} }
@ -1731,66 +1707,95 @@ namespace nlsat {
result.reset(); result.reset();
return; return;
} }
m_result = &result; unsigned base = result.size();
process(num, ls); while (true) {
reset_already_added(); try {
m_result = nullptr; m_result = &result;
TRACE(nlsat_explain, display(tout << "[explain] result\n", result) << "\n";); process(num, ls);
CASSERT("nlsat", check_already_added()); reset_already_added();
m_result = nullptr;
TRACE(nlsat_explain, display(tout << "[explain] result\n", result) << "\n";);
CASSERT("nlsat", check_already_added());
break;
}
catch (add_all_coeffs_restart const&) {
TRACE(nlsat_explain, tout << "restarting explanation with all coefficients\n";);
reset_already_added();
result.shrink(base);
m_result = nullptr;
}
}
} }
void project(var x, unsigned num, literal const * ls, scoped_literal_vector & result) { void project(var x, unsigned num, literal const * ls, scoped_literal_vector & result) {
unsigned base = result.size();
m_result = &result; while (true) {
svector<literal> lits; bool reordered = false;
TRACE(nlsat, tout << "project x" << x << "\n"; try {
m_solver.display(tout, num, ls); m_result = &result;
m_solver.display(tout);); svector<literal> lits;
TRACE(nlsat, tout << "project x" << x << "\n";
#ifdef Z3DEBUG m_solver.display(tout, num, ls);
for (unsigned i = 0; i < num; ++i) {
SASSERT(m_solver.value(ls[i]) == l_true);
atom* a = m_atoms[ls[i].var()];
SASSERT(!a || m_evaluator.eval(a, ls[i].sign()));
}
#endif
split_literals(x, num, ls, lits);
collect_polys(lits.size(), lits.data(), m_ps);
var mx_var = max_var(m_ps);
if (!m_ps.empty()) {
svector<var> renaming;
if (x != mx_var) {
for (var i = 0; i < m_solver.num_vars(); ++i) {
renaming.push_back(i);
}
std::swap(renaming[x], renaming[mx_var]);
m_solver.reorder(renaming.size(), renaming.data());
TRACE(qe, tout << "x: " << x << " max: " << mx_var << " num_vars: " << m_solver.num_vars() << "\n";
m_solver.display(tout);); m_solver.display(tout););
}
elim_vanishing(m_ps);
project(m_ps, mx_var);
reset_already_added();
m_result = nullptr;
if (x != mx_var) {
m_solver.restore_order();
}
}
else {
reset_already_added();
m_result = nullptr;
}
for (unsigned i = 0; i < result.size(); ++i) {
result.set(i, ~result[i]);
}
#ifdef Z3DEBUG #ifdef Z3DEBUG
TRACE(nlsat, m_solver.display(tout, result.size(), result.data()) << "\n"; ); for (unsigned i = 0; i < num; ++i) {
for (literal l : result) { SASSERT(m_solver.value(ls[i]) == l_true);
CTRACE(nlsat, l_true != m_solver.value(l), m_solver.display(tout, l) << " " << m_solver.value(l) << "\n";); atom* a = m_atoms[ls[i].var()];
SASSERT(l_true == m_solver.value(l)); SASSERT(!a || m_evaluator.eval(a, ls[i].sign()));
} }
#endif #endif
split_literals(x, num, ls, lits);
collect_polys(lits.size(), lits.data(), m_ps);
var mx_var = max_var(m_ps);
if (!m_ps.empty()) {
svector<var> renaming;
if (x != mx_var) {
for (var i = 0; i < m_solver.num_vars(); ++i) {
renaming.push_back(i);
}
std::swap(renaming[x], renaming[mx_var]);
m_solver.reorder(renaming.size(), renaming.data());
reordered = true;
TRACE(qe, tout << "x: " << x << " max: " << mx_var << " num_vars: " << m_solver.num_vars() << "\n";
m_solver.display(tout););
}
elim_vanishing(m_ps);
project(m_ps, mx_var);
reset_already_added();
m_result = nullptr;
if (reordered) {
m_solver.restore_order();
}
}
else {
reset_already_added();
m_result = nullptr;
}
for (unsigned i = 0; i < result.size(); ++i) {
result.set(i, ~result[i]);
}
#ifdef Z3DEBUG
TRACE(nlsat, m_solver.display(tout, result.size(), result.data()) << "\n"; );
for (literal l : result) {
CTRACE(nlsat, l_true != m_solver.value(l), m_solver.display(tout, l) << " " << m_solver.value(l) << "\n";);
SASSERT(l_true == m_solver.value(l));
}
#endif
break;
}
catch (add_all_coeffs_restart const&) {
TRACE(nlsat_explain, tout << "restarting projection with all coefficients\n";);
reset_already_added();
if (reordered) {
m_solver.restore_order();
}
result.shrink(base);
m_result = nullptr;
std::cout << "switch\n";
}
}
} }
void split_literals(var x, unsigned n, literal const* ls, svector<literal>& lits) { void split_literals(var x, unsigned n, literal const* ls, svector<literal>& lits) {

2
src/nlsat/nlsat_params.pyg
View file

@ -20,6 +20,6 @@ def_module_params('nlsat',
('inline_vars', BOOL, False, "inline variables that can be isolated from equations (not supported in incremental mode)"), ('inline_vars', BOOL, False, "inline variables that can be isolated from equations (not supported in incremental mode)"),
('seed', UINT, 0, "random seed."), ('seed', UINT, 0, "random seed."),
('factor', BOOL, True, "factor polynomials produced during conflict resolution."), ('factor', BOOL, True, "factor polynomials produced during conflict resolution."),
('add_all_coeffs', BOOL, True, "add all polynomial coefficients during projection."), ('add_all_coeffs', BOOL, False, "add all polynomial coefficients during projection."),
('known_sat_assignment_file_name', STRING, "", "the file name of a known solution: used for debugging only") ('known_sat_assignment_file_name', STRING, "", "the file name of a known solution: used for debugging only")
)) ))