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add a test with compute_conflict_explanation call

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Signed-off-by: Lev Nachmanson <levnach@hotmail.com>
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Lev Nachmanson 2026-02-18 07:08:56 -10:00
parent 05029c6f03
commit 138828259a
1 changed files with 143 additions and 0 deletions
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143
src/test/nlsat.cpp
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@ -2504,7 +2504,150 @@ static void tst_unsound_lws_nullified2() {
std::cout << "=== END tst_unsound_lws_nullified2 ===\n\n";
}
// Test that compute_conflict_explanation produces a lemma where the counterexample
// falsifies at least one literal. Reproducer from p6236_terminationG_0.smt2.
static void tst_explain_p6236() {
std::cout << "=== tst_explain_p6236 ===\n";
params_ref ps;
ps.set_bool("lws", true);
reslimit rlim;
nlsat::solver s(rlim, ps, false);
anum_manager & am = s.am();
nlsat::pmanager & pm = s.pm();
nlsat::assignment sample_as(am);
nlsat::assignment counter_as(am);
// Create 16 variables x0-x15
nlsat::var x0 = s.mk_var(false);
nlsat::var x1 = s.mk_var(false);
nlsat::var x2 = s.mk_var(false);
nlsat::var x3 = s.mk_var(false);
nlsat::var x4 = s.mk_var(false);
nlsat::var x5 = s.mk_var(false);
nlsat::var x6 = s.mk_var(false);
nlsat::var x7 = s.mk_var(false);
nlsat::var x8 = s.mk_var(false);
nlsat::var x9 = s.mk_var(false);
nlsat::var x10 = s.mk_var(false);
nlsat::var x11 = s.mk_var(false);
nlsat::var x12 = s.mk_var(false);
nlsat::var x13 = s.mk_var(false);
nlsat::var x14 = s.mk_var(false);
nlsat::var x15 = s.mk_var(false);
polynomial_ref _x0(pm), _x3(pm), _x4(pm), _x5(pm), _x6(pm);
polynomial_ref _x9(pm), _x10(pm), _x11(pm), _x13(pm), _x14(pm), _x15(pm);
_x0 = pm.mk_polynomial(x0);
_x3 = pm.mk_polynomial(x3);
_x4 = pm.mk_polynomial(x4);
_x5 = pm.mk_polynomial(x5);
_x6 = pm.mk_polynomial(x6);
_x9 = pm.mk_polynomial(x9);
_x10 = pm.mk_polynomial(x10);
_x11 = pm.mk_polynomial(x11);
_x13 = pm.mk_polynomial(x13);
_x14 = pm.mk_polynomial(x14);
_x15 = pm.mk_polynomial(x15);
// p1: -x9*x15 - x10*x14 + x5*x11*x13 + x3*x4*x11 + 2
polynomial_ref p1(pm);
p1 = -_x9 * _x15 - _x10 * _x14 + _x5 * _x11 * _x13 + _x3 * _x4 * _x11 + 2;
// p2: x15 + x6*x13 + x0*x4
polynomial_ref p2(pm);
p2 = _x15 + _x6 * _x13 + _x0 * _x4;
// Build justification literals:
// jst lit[0]: !(x15 < root[1](p1)) => literal(root_lt_bvar, true)
// jst lit[1]: !(p2 > 0) => literal(gt_bvar, true)
nlsat::bool_var root_lt_bvar = s.mk_root_atom(nlsat::atom::ROOT_LT, x15, 1, p1.get());
nlsat::literal jst_lit0(root_lt_bvar, true); // negated: !(x15 < root[1](p1))
nlsat::literal gt_lit = mk_gt(s, p2.get());
nlsat::literal jst_lit1 = ~gt_lit; // negated: !(p2 > 0)
nlsat::literal jst_lits[2] = { jst_lit0, jst_lit1 };
// Sample: x0=1,x1=-1,x2=1,x3=-1,x4=2,x5=0,x6=0,x7=0,x8=0,x9=1,x10=0,x11=1/2,x12=1,x13=-4,x14=2
scoped_anum val(am);
rational half(1, 2);
set_assignment_value(sample_as, am, x0, rational(1));
set_assignment_value(sample_as, am, x1, rational(-1));
set_assignment_value(sample_as, am, x2, rational(1));
set_assignment_value(sample_as, am, x3, rational(-1));
set_assignment_value(sample_as, am, x4, rational(2));
set_assignment_value(sample_as, am, x5, rational(0));
set_assignment_value(sample_as, am, x6, rational(0));
set_assignment_value(sample_as, am, x7, rational(0));
set_assignment_value(sample_as, am, x8, rational(0));
set_assignment_value(sample_as, am, x9, rational(1));
set_assignment_value(sample_as, am, x10, rational(0));
set_assignment_value(sample_as, am, x11, half);
set_assignment_value(sample_as, am, x12, rational(1));
set_assignment_value(sample_as, am, x13, rational(-4));
set_assignment_value(sample_as, am, x14, rational(2));
s.set_rvalues(sample_as);
// Compute conflict explanation
nlsat::explain& ex = s.get_explain();
nlsat::scoped_literal_vector result(s);
ex.compute_conflict_explanation(2, jst_lits, result);
// Build the full lemma: result literals + ~jst_lits
nlsat::literal_vector lemma;
for (unsigned i = 0; i < result.size(); ++i)
lemma.push_back(result[i]);
lemma.push_back(~jst_lits[0]); // x15 < root[1](p1)
lemma.push_back(~jst_lits[1]); // p2 > 0
std::cout << "Lemma (" << lemma.size() << " literals):\n";
s.display(std::cout << " ", lemma.size(), lemma.data()) << "\n";
// Counterexample: x0=0,x3=-1,x4=1,x5=0,x6=0,x9=1,x10=0,x11=3,x13=0,x14=0,x15=0
set_assignment_value(counter_as, am, x0, rational(0));
set_assignment_value(counter_as, am, x1, rational(-1));
set_assignment_value(counter_as, am, x2, rational(1));
set_assignment_value(counter_as, am, x3, rational(-1));
set_assignment_value(counter_as, am, x4, rational(1));
set_assignment_value(counter_as, am, x5, rational(0));
set_assignment_value(counter_as, am, x6, rational(0));
set_assignment_value(counter_as, am, x7, rational(0));
set_assignment_value(counter_as, am, x8, rational(0));
set_assignment_value(counter_as, am, x9, rational(1));
set_assignment_value(counter_as, am, x10, rational(0));
set_assignment_value(counter_as, am, x11, rational(3));
set_assignment_value(counter_as, am, x12, rational(1));
set_assignment_value(counter_as, am, x13, rational(0));
set_assignment_value(counter_as, am, x14, rational(0));
set_assignment_value(counter_as, am, x15, rational(0));
// Set counterexample as the solver's assignment for evaluation
s.set_rvalues(counter_as);
nlsat::evaluator& ev = s.get_evaluator();
// Check unsat
bool unsat = true;
for (unsigned i = 0; i < lemma.size(); ++i) {
nlsat::literal lit = lemma[i];
nlsat::atom* a = s.bool_var2atom(lit.var());
if (a == nullptr)
continue;
bool sat = ev.eval(a, lit.sign());
std::cout << " lit[" << i << "]: ";
s.display(std::cout, lit) << " = " << (sat ? "true" : "false") << "\n";
if (sat)
unsat = false;
}
ENSURE(unsat);
std::cout << "=== END tst_explain_p6236 ===\n\n";
}
void tst_nlsat() {
tst_explain_p6236();
std::cout << "------------------\n";
tst_unsound_lws_p6236();
std::cout << "------------------\n";
tst_unsound_lws_disc_zero();