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restore the square-free check

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
This commit is contained in:
Lev Nachmanson 2025-08-11 13:16:37 -07:00
parent e33dc47d83
commit cf8a17a6ae
1 changed files with 42 additions and 9 deletions
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51
src/nlsat/nlsat_explain.cpp
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@ -618,22 +618,55 @@ namespace nlsat {
} }
} }
// For each p in ps add the leading coefficent to the projection, // The monomials have to be square free according to
void add_lc(polynomial_ref_vector &ps, var x) { //"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) {
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.
// Otherwise, add each coefficient of each p to the projection.
void add_lcs(polynomial_ref_vector &ps, var x) {
polynomial_ref p(m_pm); polynomial_ref p(m_pm);
polynomial_ref coeff(m_pm); polynomial_ref coeff(m_pm);
// Add coefficients based on well-orientedness bool sqf = is_square_free(ps, x);
// 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);
unsigned k_deg = m_pm.degree(p, x); unsigned k_deg = m_pm.degree(p, x);
if (k_deg == 0) continue; if (k_deg == 0) continue;
// p depends on x // p depends on x
TRACE(nlsat_explain, tout << "processing poly of degree " << k_deg << " w.r.t x" << x << ": "; display(tout, p) << "\n";); TRACE(nlsat_explain, tout << "processing poly of degree " << k_deg << " w.r.t x" << x << ": "; display(tout, p) << "\n";);
coeff = m_pm.coeff(p, x, k_deg); for (unsigned j_coeff_deg = k_deg; j_coeff_deg >= 1; j_coeff_deg--) {
TRACE(nlsat_explain, tout << " coeff deg " << k_deg << ": "; display(tout, coeff) << "\n";); coeff = m_pm.coeff(p, x, j_coeff_deg);
insert_fresh_factors_in_todo(coeff); TRACE(nlsat_explain, tout << " coeff deg " << j_coeff_deg << ": "; display(tout, coeff) << "\n";);
insert_fresh_factors_in_todo(coeff);
if (sqf)
break;
}
} }
} }
@ -1175,7 +1208,7 @@ namespace nlsat {
TRACE(nlsat_explain, tout << "project loop, processing var "; display_var(tout, x); TRACE(nlsat_explain, tout << "project loop, processing var "; display_var(tout, x);
tout << "\npolynomials\n"; tout << "\npolynomials\n";
display(tout, ps); tout << "\n";); display(tout, ps); tout << "\n";);
add_lc(ps, x); add_lcs(ps, x);
psc_discriminant(ps, x); psc_discriminant(ps, x);
psc_resultant(ps, x); psc_resultant(ps, x);
if (m_todo.empty()) if (m_todo.empty())
@ -1223,7 +1256,7 @@ namespace nlsat {
} }
TRACE(nlsat_explain, tout << "project loop, processing var "; display_var(tout, x); tout << "\npolynomials\n"; TRACE(nlsat_explain, tout << "project loop, processing var "; display_var(tout, x); tout << "\npolynomials\n";
display(tout, ps); tout << "\n";); display(tout, ps); tout << "\n";);
add_lc(ps, x); add_lcs(ps, x);
psc_discriminant(ps, x); psc_discriminant(ps, x);
psc_resultant(ps, x); psc_resultant(ps, x);