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patch for Sturm sequence bug #4961

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This commit is contained in:
Nikolaj Bjorner 2021-01-24 12:58:25 -08:00
parent 2d1684bc2d
commit 7d60d8462d
4 changed files with 124 additions and 114 deletions
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18
src/math/polynomial/algebraic_numbers.cpp
View file

@ -1844,6 +1844,23 @@ namespace algebraic_numbers {
}
}
// workaround: Sturm sequences are buggy as exemplified by several open github issues
// instead of relying on Sturm check if a simple interval expansion allows to separate
// a and b.
scoped_mpbq la(bqm()), ua(bqm());
scoped_mpbq lb(bqm()), ub(bqm());
unsigned precision = 10;
if (get_interval(a, la, ua, precision) &&
get_interval(b, lb, ub, precision)) {
IF_VERBOSE(9, verbose_stream() << "sturm 0\n");
if (la > ub)
return sign_pos;
if (ua < lb)
return sign_neg;
}
IF_VERBOSE(9, verbose_stream() << "sturm 1\n");
//
// EXPENSIVE CASE
// Let seq be the Sturm-Tarski sequence for
// p_a, p_a' * p_b
@ -1864,6 +1881,7 @@ namespace algebraic_numbers {
// if (V < 0) == (p_b(b_lower) < 0) then b > a else b < a
//
m_compare_sturm++;
upolynomial::scoped_upolynomial_sequence seq(upm());
upm().sturm_tarski_seq(cell_a->m_p_sz, cell_a->m_p, cell_b->m_p_sz, cell_b->m_p, seq);

39
src/nlsat/nlsat_interval_set.cpp
View file

@ -71,20 +71,15 @@ namespace nlsat {
}
bool check_interval(anum_manager & am, interval const & i) {
if (i.m_lower_inf) {
SASSERT(i.m_lower_open);
}
if (i.m_upper_inf) {
SASSERT(i.m_upper_open);
}
SASSERT(!i.m_lower_inf || i.m_lower_open);
SASSERT(!i.m_upper_inf || i.m_upper_open);
if (!i.m_lower_inf && !i.m_upper_inf) {
auto s = am.compare(i.m_lower, i.m_upper);
TRACE("nlsat_interval", tout << "lower: "; am.display_decimal(tout, i.m_lower); tout << ", upper: "; am.display_decimal(tout, i.m_upper);
tout << "\ns: " << s << "\n";);
SASSERT(s <= 0);
if (::is_zero(s)) {
SASSERT(!i.m_lower_open && !i.m_upper_open);
}
SASSERT(!is_zero(s) || !i.m_lower_open && !i.m_upper_open);
}
return true;
}
@ -92,12 +87,10 @@ namespace nlsat {
bool check_no_overlap(anum_manager & am, interval const & curr, interval const & next) {
SASSERT(!curr.m_upper_inf);
SASSERT(!next.m_lower_inf);
int sign = am.compare(curr.m_upper, next.m_lower);
CTRACE("nlsat", sign > 0, display(tout, am, curr); tout << " "; display(tout, am, next); tout << "\n";);
SASSERT(sign <= 0);
if (sign == 0) {
SASSERT(curr.m_upper_open || next.m_lower_open);
}
sign s = am.compare(curr.m_upper, next.m_lower);
CTRACE("nlsat", s > 0, display(tout, am, curr); tout << " "; display(tout, am, next); tout << "\n";);
SASSERT(s <= 0);
SASSERT(!is_zero(s) || curr.m_upper_open || next.m_lower_open);
return true;
}
@ -107,9 +100,7 @@ namespace nlsat {
for (unsigned i = 0; i < sz; i++) {
interval const & curr = ints[i];
SASSERT(check_interval(am, curr));
if (i < sz - 1) {
SASSERT(check_no_overlap(am, curr, ints[i+1]));
}
SASSERT(i >= sz - 1 || check_no_overlap(am, curr, ints[i+1]));
});
return true;
}
@ -276,10 +267,9 @@ namespace nlsat {
interval_set * interval_set_manager::mk_union(interval_set const * s1, interval_set const * s2) {
#if 0
// issue #2867:
static unsigned s_count = 0;
s_count++;
if (s_count == 8442) {
if (s_count == 4470) {
enable_trace("nlsat_interval");
enable_trace("algebraic");
}
@ -416,7 +406,7 @@ namespace nlsat {
else {
SASSERT(l1_l2_sign > 0);
if (u1_u2_sign == 0) {
TRACE("nlsat_interval", tout << "l1_l2_sign > 0, u1_u2_sign == 0\n";);
TRACE("nlsat_interval", tout << "l2 < l1 <= u1 = u2\n";);
// Case:
// 1) [ ]
// [ ]
@ -426,7 +416,7 @@ namespace nlsat {
i2++;
}
else if (u1_u2_sign < 0) {
TRACE("nlsat_interval", tout << "l1_l2_sign > 0, u1_u2_sign > 0\n";);
TRACE("nlsat_interval", tout << "l2 < l1 <= u2 < u2\n";);
// Case:
// 1) [ ]
// [ ]
@ -436,7 +426,7 @@ namespace nlsat {
else {
auto u2_l1_sign = compare_upper_lower(m_am, int2, int1);
if (u2_l1_sign < 0) {
TRACE("nlsat_interval", tout << "l1_l2_sign > 0, u1_u2_sign > 0, u2_l1_sign < 0\n";);
TRACE("nlsat_interval", tout << "l2 <= u2 < l1 <= u1\n";);
// Case:
// 1) [ ]
// [ ]
@ -457,7 +447,7 @@ namespace nlsat {
i2++;
}
else {
TRACE("nlsat_interval", tout << "l1_l2_sign > 0, u1_u2_sign > 0, u2_l1_sign > 0\n";);
TRACE("nlsat_interval", tout << "l2 < l1 < u2 < u1\n";);
SASSERT(l1_l2_sign > 0);
SASSERT(u1_u2_sign > 0);
SASSERT(u2_l1_sign > 0);
@ -474,6 +464,7 @@ namespace nlsat {
}
SASSERT(result.size() <= 1 ||
check_no_overlap(m_am, result[result.size() - 2], result[result.size() - 1]));
}
SASSERT(!result.empty());

29
src/util/mpbq.cpp
View file

@ -57,9 +57,8 @@ mpbq_manager::~mpbq_manager() {
}
void mpbq_manager::reset(mpbq_vector & v) {
unsigned sz = v.size();
for (unsigned i = 0; i < sz; i++)
reset(v[i]);
for (auto & e : v)
reset(e);
v.reset();
}
@ -391,23 +390,25 @@ std::string mpbq_manager::to_string(mpbq const & a) {
return buffer.str();
}
void mpbq_manager::display(std::ostream & out, mpbq const & a) {
std::ostream& mpbq_manager::display(std::ostream & out, mpbq const & a) {
out << m_manager.to_string(a.m_num);
if (a.m_k > 0)
out << "/2";
if (a.m_k > 1)
out << "^" << a.m_k;
return out;
}
void mpbq_manager::display_pp(std::ostream & out, mpbq const & a) {
std::ostream& mpbq_manager::display_pp(std::ostream & out, mpbq const & a) {
out << m_manager.to_string(a.m_num);
if (a.m_k > 0)
out << "/2";
if (a.m_k > 1)
out << "<sup>" << a.m_k << "</sup>";
return out;
}
void mpbq_manager::display_smt2(std::ostream & out, mpbq const & a, bool decimal) {
std::ostream& mpbq_manager::display_smt2(std::ostream & out, mpbq const & a, bool decimal) {
if (a.m_k == 0) {
m_manager.display_smt2(out, a.m_num, decimal);
}
@ -421,12 +422,12 @@ void mpbq_manager::display_smt2(std::ostream & out, mpbq const & a, bool decimal
if (decimal) out << ".0";
out << "))";
}
return out;
}
void mpbq_manager::display_decimal(std::ostream & out, mpbq const & a, unsigned prec) {
std::ostream& mpbq_manager::display_decimal(std::ostream & out, mpbq const & a, unsigned prec) {
if (is_int(a)) {
out << m_manager.to_string(a.m_num);
return;
return out << m_manager.to_string(a.m_num);
}
mpz two(2);
mpz ten(10);
@ -455,17 +456,16 @@ void mpbq_manager::display_decimal(std::ostream & out, mpbq const & a, unsigned
m_manager.del(n1);
m_manager.del(v1);
m_manager.del(two_k);
return out;
}
void mpbq_manager::display_decimal(std::ostream & out, mpbq const & a, mpbq const & b, unsigned prec) {
std::ostream& mpbq_manager::display_decimal(std::ostream & out, mpbq const & a, mpbq const & b, unsigned prec) {
mpz two(2);
mpz ten(10);
mpz two_k1, two_k2;
mpz n1, v1, n2, v2;
if (m_manager.is_neg(a.m_num) != m_manager.is_neg(b.m_num)) {
out << "?";
return;
}
if (m_manager.is_neg(a.m_num) != m_manager.is_neg(b.m_num))
return out << "?";
if (m_manager.is_neg(a.m_num))
out << "-";
m_manager.set(v1, a.m_num);
@ -512,6 +512,7 @@ void mpbq_manager::display_decimal(std::ostream & out, mpbq const & a, mpbq cons
m_manager.del(v2);
m_manager.del(two_k1);
m_manager.del(two_k2);
return out;
}
bool mpbq_manager::to_mpbq(mpq const & q, mpbq & bq) {

10
src/util/mpbq.h
View file

@ -258,17 +258,17 @@ public:
void select_small_core(unsynch_mpq_manager & qm, mpq const & lower, mpq const & upper, mpbq & r);
void display(std::ostream & out, mpbq const & a);
void display_pp(std::ostream & out, mpbq const & a);
void display_decimal(std::ostream & out, mpbq const & a, unsigned prec = 8);
std::ostream& display(std::ostream & out, mpbq const & a);
std::ostream& display_pp(std::ostream & out, mpbq const & a);
std::ostream& display_decimal(std::ostream & out, mpbq const & a, unsigned prec = 8);
/**
\brief Display a in decimal while its digits match b digits.
This function is useful when a and b are representing an interval [a,b] which
contains an algebraic number
*/
void display_decimal(std::ostream & out, mpbq const & a, mpbq const & b, unsigned prec);
std::ostream& display_decimal(std::ostream & out, mpbq const & a, mpbq const & b, unsigned prec);
void display_smt2(std::ostream & out, mpbq const & a, bool decimal);
std::ostream& display_smt2(std::ostream & out, mpbq const & a, bool decimal);
/**
\brief Approximate n as b/2^k' s.t. k' <= k.