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try replace fail with a adding partial derivatives

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2026-02-17 13:20:50 -10:00
parent 9ef99f57e8
commit 2d8e866e19
1 changed files with 37 additions and 15 deletions
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52
src/nlsat/levelwise.cpp
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@ -4,7 +4,6 @@
#include "math/polynomial/algebraic_numbers.h"
#include "math/polynomial/polynomial.h"
#include "nlsat_common.h"
#include "util/z3_exception.h"
#include "util/vector.h"
#include "util/trace.h"
@ -44,7 +43,6 @@ namespace nlsat {
sector_spanning_tree
};
struct nullified_poly_exception {};
struct levelwise::impl {
solver& m_solver;
@ -265,7 +263,41 @@ namespace nlsat {
m_spanning_tree_threshold = m_solver.lws_spt_threshold();
}
void fail() { throw nullified_poly_exception(); }
// Handle a polynomial whose every coefficient evaluates to zero at the sample.
// Compute partial derivatives level by level. If all derivatives at a level vanish,
// request_factorized each of them and continue to the next level.
// When a non-vanishing derivative is found, request_factorized it and stop.
void handle_nullified_poly(polynomial_ref const& p) {
m_fail = true;
polynomial_ref_vector current(m_pm);
current.push_back(p);
while (!current.empty()) {
polynomial_ref_vector next_derivs(m_pm);
for (unsigned i = 0; i < current.size(); ++i) {
polynomial_ref q(current.get(i), m_pm);
unsigned mv = m_pm.max_var(q);
if (mv == null_var)
continue;
for (unsigned x = 0; x <= mv; ++x) {
if (m_pm.degree(q, x) == 0)
continue;
polynomial_ref dq = derivative(q, x);
if (!dq || is_zero(dq) || is_const(dq))
continue;
if (m_am.eval_sign_at(dq, sample()) != 0) {
request_factorized(dq);
return;
}
next_derivs.push_back(dq);
}
}
for (unsigned i = 0; i < next_derivs.size(); ++i) {
polynomial_ref dq(next_derivs.get(i), m_pm);
request_factorized(dq);
}
current = std::move(next_derivs);
}
}
static void reset_interval(root_function_interval& I) {
I.section = false;
@ -1180,7 +1212,7 @@ namespace nlsat {
polynomial_ref p(m_level_ps.get(i), m_pm);
polynomial_ref w = choose_nonzero_coeff(p, m_level);
if (!w)
fail();
handle_nullified_poly(p);
m_witnesses.push_back(w);
}
}
@ -1246,7 +1278,7 @@ namespace nlsat {
}
}
std_vector<root_function_interval> single_cell_work() {
std_vector<root_function_interval> single_cell() {
TRACE(lws,
tout << "Input polynomials (" << m_P.size() << "):\n";
for (unsigned i = 0; i < m_P.size(); ++i)
@ -1293,16 +1325,6 @@ namespace nlsat {
return m_I;
}
std_vector<root_function_interval> single_cell() {
try {
return single_cell_work();
}
catch (nullified_poly_exception&) {
m_fail = true;
return m_I;
}
}
};
levelwise::levelwise(